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Title: Canning, Freezing, Storing Garden Produce
Author: Various
Language: English
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*** Start of this LibraryBlog Digital Book "Canning, Freezing, Storing Garden Produce" ***
Canning, Freezing, Storing Garden Produce
United States Department of Agriculture
Agriculture Information Bulletin 410
This is a reprint of Part 4 from the 1977 Yearbook of Agriculture,
_Gardening for Food and Fun_. The Yearbook may be purchased at
government bookstores or ordered from the Superintendent of Documents,
U.S. Government Printing Office, Washington, D.C. 20402. Original page
numbers from the entire book are used in this reprint.
Contents
Part 4 Home Food Preservation
_The Whys of Food Preservation_ 298
_How to Minimize Quality Losses_ 304
_Economics of Home Food Preservation, or Is Do-It-Yourself
Back to Stay?_ 310
_Beginner’s Guide to Home Canning_ 313
_A Primer on Home Freezing for the Beginner_ 320
_Pressure Canners, Vital for Low-Acid Foods_ 323
_Home Canning of Fruits and Vegetables_ 328
_Freezing Your Garden’s Harvest_ 334
_Jellies, Jams, Marmalades, Preserves_ 340
_Pickles, Relishes Add Zip and Zest_ 345
_Wine Making (with a note on vinegar)_ 350
_Home Drying of Fruits and Vegetables_ 356
_Storage of Home-Preserved Foods_ 361
_Storing Fresh Fruit and Vegetables_ 365
_Resurgence of Community Canneries_ 372
_Questions and Answers on Food Preservation_ 378
_Food Preservation Glossary_ 383
Issued in December 1977
PART 4 Home Food Preservation
[Illustration: Fresh and preserved foods]
The Whys of Food Preservation
_by Edmund A. Zottola and Isabel D. Wolf_[1]
The telephone rings in a county Extension office. A harried voice says,
“My garden is growing more than my family can eat, what shall I do with
it? How can I keep it from spoiling?”
How many times during the gardening season is this scenario repeated in
an Extension office? Too often to count! The answers to these questions
are readily available in the many bulletins, folders, and leaflets on
food preservation available from county, State, and Federal Extension
agencies. The publications tell how to preserve food safely and
wholesomely, but do little else to explain why directions must be
followed precisely. Let’s take a look at the whys.
To understand food preservation, first consider the sources. Home garden
food comes from plants: sources of raw food are living, biological
entities, continuing to metabolize after they are harvested. Plants also
provide a source of food for micro-organisms which can grow on or in
them, spoiling food before it can be eaten. The primary objective of
food preservation is to prevent food spoilage by preserving food until
it can be used by people.
Historically, food preservation and processing assured a food supply and
prevented starvation. This is probably the major reason why food is
processed today in many developing countries. In the United States,
however, affluence and a plentiful food supply now influence the reasons
for food preservation. Today, Americans live many miles from rural areas
where food is produced. Consequently, food must be preserved to assure
the nonfarm population an adequate supply.
Our people want a food supply that is safe, high in quality and
appearance, adequate nutritionally, and reasonably priced. Many
consumers try to obtain these food attributes by returning to the “old
ways” of growing and preserving food themselves.
To understand food preservation, let’s look at five causes of food
spoilage or deterioration (four are biological, the fifth physical or
mechanical):
(1) The primary cause of food spoilage in the United States is
microbiological. Micro-organisms are small living organisms such as
yeast, molds, or bacteria. They are the chief causes of microbial
spoilage.
Related to microbiological spoilage of food and also a concern in food
preservation is microbiological food-borne disease. There are two types.
Salmonellosis is an example of a food infection where food may not
support growth of the micro-organisms but merely serves to transfer it
from the source to the human host. In the second type, the
micro-organism grows in the food and produces a poison or toxin which
when eaten, causes illness symptoms. Staphylococcal food poisoning is
the most common of the second type in the US.
Severity of the major types of food-borne disease in the United States
varies from the finality of botulism to the mild discomforts of
_Clostridium perfringens_ food poisoning. Food preservation techniques,
followed precisely, prevent food-borne disease.
(2) The second cause of food spoilage is vermin such as rodents, rats,
mice and insects that attack the food and eat or contaminate it before
humans can use it. These vermin ruin millions of pounds of food each
year.
[Illustration: WHAT ELSE CAN WE DO WITH TOMATOES?!!]
(3) Have you noticed how an apple, left at room temperature, eventually
gets soft, wrinkles, and dries out? This spoilage is called senescence:
an aging process caused by continued respiration of the apple,
eventually making it useless as food. Other foods also spoil this way.
(4) Related to senescence is chemical deterioration of food. The
development of rancid flavor in high fat-containing foods is a chemical
reaction which brings about an undesirable change. Loss of color or
bleaching and loss of vitamins, while food is stored, are chemical
deteriorations that can be controlled with proper preservation methods.
Both senescence and chemical deterioration are conveyed by organic
compounds called enzymes. These enzymes are produced by all living
organisms and their function is to speed up or cause the metabolic
reaction necessary for the organism’s continued existence. The enzymes
will continue to act after the plant is harvested, and bring about
deterioration of the food unless controlled or destroyed. Preservation
methods have been developed to control or destroy these organic
catalysts.
(5) The last cause of food spoilage concerns food handling. Physical or
mechanical damage to the food causes bruising, crushing, cutting, and
wilting or water loss. These mechanical defects, besides detracting from
the food’s appearance, allow easier entry of micro-organisms, insects,
and other vermin to cause spoilage and aging.
Food preservation processes have been developed to slow down, prevent,
or stop completely these processes of food spoilage.
An inherent part of food preservation is the package containing the food
before or after processing.
Packaging provides a convenient method of handling food, prevents
contamination during and after processing, bars vermin infestation,
supplies a container for storage, and is a necessary part of
preservation. An example would be a mason jar with proper seal for
pickling.
What are the major methods available for home preservation of food? How
are they carried out? Why do they prevent spoilage, food-borne disease,
and give desired attributes of safety, quality, appearance, nutrition,
and economy? The economics of food preservation will be developed in a
subsequent chapter. Let’s explore the following available methods for
home preservation of food:
—Control of temperature of the food, heat or cool
—Control of the food’s acid content
—Control of moisture content of the food
The major method used for home preservation of food is temperature
control. This includes canning with a pressure canner or a boiling water
bath, blanching food before freezing, refrigerating food, and freezing
it. Micro-organisms which cause disease and food spoilage are sensitive
to environment temperature variations. By increasing the food’s
temperature, micro-organisms are destroyed. When the temperature is
decreased, their growth is inhibited.
Let’s look at the temperature scale illustration and see how temperature
affects micro-organisms. To prevent growth of micro-organisms in food
and subsequent microbial spoilage, food must be kept out of the
temperature range that allows growth. This is most commonly achieved by
refrigerating or freezing. Refrigeration slows down or stops microbial
spoilage. Freezing stops it completely.
[Illustration: EFFECT OF TEMPERATURE ON MICRO-ORGANISMS]
Degrees
Fahrenheit
225 spore-forming bacteria killed
220-250 proper canning temperatures (low acid foods)
212 water boils; pressure canner needed to obtain
temperatures above boiling
170-210 non-spore-forming bacteria, yeasts, and molds killed
120-140 some bacteria can grow
98.6 body temperature
70-80 room temperatures may fall in this range
60-120 DANGER ZONE
most bacteria, including food-poisoning types, grow
rapidly over this temperature range
32 water freezes
30-60 cold-tolerant bacteria, yeasts and molds grow
0 no microbial growth
Enzymatic activity, while slowed down by freezing, is not stopped in
many vegetables and these enzymes must be destroyed by blanching the
vegetables before freezing to prevent enzymatic deterioration.
Successful preservation by freezing must deactivate any enzymes that
might be in the food as well as rapidly lower the food temperature to
below freezing to stop microbial activity.
Freezer burn, a common problem with frozen foods, comes from improper
packaging. Food moisture is lost in freezer burn, which results in
undesirable flavor and texture changes. Freezer burn can be controlled
by proper packaging, proper storing temperature, and avoiding long-term
storage.
Refrigeration or storage above freezing, but below room temperature,
preserves food for days and sometimes weeks. Refrigerated storage slows
down activities of enzymes in the food and reduces metabolism of the
contaminating micro-organisms.
Preservation of food by reduced temperature, refrigeration, or freezing
is achieved because enzyme activity and microbial deterioration are
slowed down or stopped.
Increasing the temperature of food to achieve preservation also results
in destruction of the micro-organisms that produce spoilage and disease.
Time and temperature regulate this preservation. Theoretically, since
food will be stored at temperatures which will allow most microbes to
grow, the ideal heat treatment needed to preserve the food would be one
that completely sterilizes the food, that is, kills all attendant
micro-organisms. To achieve complete sterilization, for example, every
particle of food in a jar must reach the required temperature and be
held there long enough to destroy all micro-organisms.
Heat Transfer
The time required for heat to penetrate to the center of the food in a
container (the slowest heating point) is extremely important. Heat is
transferred through food in containers by two mechanisms: conduction and
convection. The mechanism involved depends on the consistency and amount
of liquid in the food. The heat penetration rate is also influenced by
size of the container, type of heating medium (wet steam vs. dry air),
ratio of solid to liquid, kind and size of solid material in container,
amount of fat, and amount of salt and sugar.
For example, pumpkin or squash can be home canned in two forms: strained
or cubed. University of Minnesota research has shown that the time
required for the center of a pint jar of strained squash (which heats by
conduction) to reach sterilization temperature is three to four times as
long as for a pint jar of cubed squash (which heats by convection). The
same is true of creamed corn (heats by conduction) and whole kernel corn
(heats by convection).
Methods and recipes recommended by Extension agencies take into account
all of these factors and must be followed precisely to assure a safe and
wholesome product.
Why is it necessary to heat-process pint jars of string beans at 240° F
for 20 minutes in a pressure canner when tomatoes can be successfully
heat-processed in a boiling water bath? This brings up the second method
of preserving food at home, controlling the food’s acid content. This
method is most commonly used in combination with heat processing.
Most foods contain naturally occurring organic acids. Some foods contain
more of these acids and are called acid or high acid foods. These
organic acids have the ability to limit, inhibit, or prevent the growth
of many of the micro-organisms producing spoilage and disease. The
degree of inhibition is related to the amount of acid present.
A method used for measuring acid content is called pH. A measure of pH
is a determination of the hydrogen ion concentration which reflects the
amount of acid or alkali present in the system. A scale from 0 to 14 is
used. A pH of 7 is considered neutral, above 7 alkaline, below 7 acidic.
Very few foods have a pH above 7.
The classification of foods in the acid range below 7 is extremely
important. Above pH 4.6 most of the spoilage type micro-organisms can
grow, as well as the dreaded _Clostridium botulinum_ (see discussion
following on botulism). In foods with a pH greater than 4.6, it is
necessary to heat-process the food at temperatures above boiling to
obtain the desired level of sterility.
There are some types of bacteria that produce entities called endospores
or spores which are extremely resistant to environmental stresses. They
are a means of assuring survival in bacteria, although not themselves a
reproductive mechanism. One growing or vegetative cell will produce one
spore, which under proper growth conditions will germinate and produce
one cell. This one cell continues to grow and can produce millions of
bacterial cells. Destruction of the resistant spore necessitates the use
of temperatures above that of boiling water (212° F).
_BOTULISM._ One of the most notorious of the spore-forming bacteria is
_Clostridium botulinum_. When growing in food this bacteria can produce
a deadly poison which causes botulism, a deadly illness. The mortality
rate is 56 percent. This bacteria and its spore are present in soil
throughout the world and as a result contaminates most of the food we
eat. But the spore only germinates and grows where there is suitable
food, no air, and a pH above 4.6. These conditions exist in canned low
acid foods.
To assure botulism-free home-canned foods, it is absolutely essential
that low-acid foods be canned in a pressure canner at temperatures above
212° F. The poison produced by this bacteria is one of the most potent
poisons known to humans. It has been estimated that 1 cup (8 ounces) is
sufficient to kill all the humans on earth. It is not something to take
chances about. All home canning procedures recommended by Federal and
State Extension agencies are adequate to destroy this dreaded
spore-forming bacteria.
[Illustration: pH VALUE OF VARIOUS FOODS]
High Acid
2.9 plums
3.0 gooseberries
3.2 dill pickles, apricots
3.3 apples, blackberries
3.4 sour cherries, peaches
3.5 kraut, raspberries
3.7 blueberries
3.8 sweet cherries
3.9 pears
4.3 tomatoes
4.6 ————
Low Acid
4.8 okra
5.0 pumpkins, carrots
5.1 turnips
5.2 beets, string beans
5.4 sweet potatoes
5.5 spinach, asparagus
5.6 baked beans
5.7 red kidney beans
5.9 lima beans
6.0 succotash
6.2 peas
6.3 corn
7.0 hominy, ripe olives
Commercial canneries, which are regulated by the Food and Drug
Administration, use similar processes to assure safe canned foods. In
the past 50 years, 75 percent of the reported cases of botulism in the
United States have been caused by home-canned food while less than 10
percent have been caused by commercially canned food. If proper
home-canning procedures are followed, botulism from this source could
virtually be eliminated as a cause of death in the US.
On the lower side of pH 4.6, acid content of the food will prevent
growth of _Clostridium botulinum_ and most of the other spore-forming
bacteria. Thus, these foods can be preserved by using a lower heat
treatment. The most common types of spoilage micro-organisms associated
with acid foods are yeasts and molds. These organisms are acid-tolerant
and can grow in an acid environment. They are killed at a lower
temperature than spore-forming bacteria. Acid foods only need a heat
treatment in a boiling water bath for a specified time to destroy the
microbes present.
Fermentation
Preservation of food by controlling the acid content can be achieved in
two ways. One is to naturally ferment the food—turning cabbage into
sauerkraut. The other is to add an organic acid to the food to reduce
the pH—adding vinegar to cucumbers to make pickles. Some foods such as
berries and fruits naturally contain enough organic acids so their pH is
below 4.6, and preservation of these foods requires only a boiling water
bath heat treatment or freezing.
In a natural fermentation, lactic acid bacteria convert fermentable
carbohydrates in the food to lactic acid. In this way the pH is reduced
and most bacterial growth inhibited. When cabbage is fermented to
sauerkraut, the cabbage’s pH is reduced from pH 6.8 during the
fermentation to less than 3.5. Cucumbers can also be fermented to
pickles by a similar process; however, most pickles are made by direct
acidification of the cucumbers.
Direct acidification, that is, adding vinegar which contains 4 to 5
percent acetic acid, is the most common method of making cucumber
pickles in the United States. It is easier, quicker, and foolproof.
Often the natural fermentation will go astray. Other undesirable
microbes may grow, bringing unwanted changes in the food: spoiling
rather than preserving. Other foods made by fermentation include wine.
Regardless of the method used to control the pH of food, to successfully
preserve food by this method it is absolutely essential to heat-process
or freeze to prevent spoilage by yeasts and molds. An example of
spoilage in cucumber pickles not heat-treated after acidification is the
development of cloudiness and bubbling. This common spoilage is caused
by microbes that would be destroyed by heat processing.
Drying
Control of the moisture content of food is one of the oldest
preservation methods. Removal of water from the food prevents growth of
most microbes and slows down enzymatic deterioration.
Water removal from food can have several forms. The oldest and most
primitive method for removing water is sun drying, which requires long
hot days with low humidity to dry food evenly and quickly. Over-drying
and uneven drying will result in nutrient destruction, microbial growth,
and other undesirable changes. Drying of food in the home can be done
and a later chapter tells how.
Water activity or availability of water in foods can also be controlled
by adding compounds to the food which tie up the water chemically,
making it unavailable for use in an enzymatic reaction or for use by the
micro-organisms. The two most common home ingredients used in this way
are sugar and salt. In making fruit preserves, the high sugar content
ties up the water and helps prevent growth of many micro-organisms.
Methods used for preserving food in the home are combinations of the
basic techniques discussed here. Make certain the recipe you follow is
from a reliable source. Follow it precisely and be assured of a safe and
wholesome food supply.
How to Minimize Quality Losses
_by Gerald D. Kuhn and Louise W. Hamilton_[2]
All methods of preserving food will alter, if not lower, the quality of
fresh fruits and vegetables, but these changes can be minimized. For
practical understanding of how to minimize quality changes you need to
know something about: (1) natural differences in raw food, (2) natural
causes of quality deterioration, and (3) how various food handling,
preparation, packaging and storage techniques and conditions affect
quality retention.
Because of insufficient research information on home preserved foods,
some research findings of commercially processed food have been used to
foster an increased awareness of factors affecting the quality of home
preserved food.
Natural differences in quality and nutrient content in raw food often
exceed losses caused by preserving food. Extreme variations (tenfold or
more) in vitamin A and C content have been found in some fruits and
vegetables. These natural differences are known to be caused singly or
collectively by differences between varieties, climate changes between
seasons in the same region, and between regions in the same year. They
are also influenced by some cultural practices, and maturity of crops at
harvest.
Because of color, texture and especially flavor qualities, some
varieties are more suited for canning; others are more suitable for
freezing. Few varieties possess the all-purpose criteria needed to
preserve them as either high-quality canned or frozen products.
There is no single, ideal maturity for harvesting or preserving fruits
and vegetables. Obviously, the quality of canned or frozen products made
from any maturity other than ideal for that specific commodity lacks the
ultimate potential of satisfaction for eating.
Three natural causes account for most quality changes in freshly
harvested fruits and vegetables—respiration, enzymes and oxygen. Their
effects generally increase with the time between harvest and
preservation, and at higher temperatures.
Freshly harvested fruits and vegetables are living organisms. They are
sustained by cellular reactions known as “respiration,” in which native
enzymes use oxygen and components in food and give off heat, water and
carbon dioxide. The energy needed to sustain respiration is obtained
from a storehouse of natural components in food. As a result, natural
flavors and vitamins are diminished, sugars and sometimes acids
decrease, and texture may soften. The speed of respiration and the onset
of its effects differs among various fruits and vegetables, and is
generally lowered by refrigerator temperatures.
Besides enzymes relating to respiration, fruits and vegetables sometimes
contain other cellular enzymes associated with reducing food quality.
These enzymes act with oxygen to cause rapid discoloration of bruised,
peeled and sliced tissue; oxidation of flavors, and excessive softening.
The roles of oxygen in respiration and other enzyme reactions have been
noted. Oxygen may react still another way to lower food quality:
autoxidation, where sensitive flavor, color and vitamin components are
altered by oxygen. This causes fading of colors, off-flavors and,
reduced vitamin retention. These reactions occur quickly during canning
and drying of foods, and also account for slow changes during storage of
preserved food.
Handling Raw Foods
Because of the effects of respiration, other enzymes, autoxidation, and
desiccation (loss of water), the raw product temperature and the time
between harvest and preservation are of utmost importance to preserving
high-quality fruits and vegetables.
Ideal handling conditions vary with the product. Small berry and stone
fruits, asparagus, green beans, beets, broccoli, corn and leafy greens,
to name a few, should be preserved the same day of harvest, for highest
quality. Apples, peaches, pears, plums and tomatoes, if harvested at
firm maturity, should be ripened a few days before preserving them.
Other fruits and vegetables may be stored from a week to months before
preservation without significantly lowering their quality.
From a nutritional standpoint, if after harvest the handling and
preservation of these crops are carefully planned and implemented,
quality of the preserved products can be equal to food prepared from
fresh market fruits and vegetables.
Fruits and vegetables are recognized as significant sources of vitamins
A, the B family, C, minerals, and fiber.
Vitamin A, pro-carotene, is heat-stable and insoluble in water but is
subject to a minor loss caused by autoxidation. Therefore, losses in
home preserved foods are insignificant.
Of the water-soluble vitamins, ascorbic acid (C) and thiamin (B₁) are
subject to serious loss upon heating foods. Riboflavin (B₂) is subject
to loss when raw or preserved foods are exposed to light.
[Illustration: Removing the skins from peaches before canning.]
Significant losses of water-soluble vitamins and minerals occur when
food contacts water, such as in washing, blanching, cooking or canning
foods. As would be expected, losses due to leaching of water-soluble
vitamins and minerals rise with increased cut or exposed food surface
areas, repeated exposures to water, and more time in water, especially
when heated.
The effects on fiber in preserved food is much the same as in fresh
cooked foods.
Canning
Home canned foods should have a bright color, characteristic texture,
pleasant flavor and contain nutrients naturally present. When all steps
of scientifically based canning directions are carefully followed,
color, texture and flavor will be optimum. These observable signs of
quality are also an index to nutrient retention of that canned food.
Proper pretreatment of the fruit or vegetable being canned is essential
for top quality. This includes using only good, wholesome food at peak
eating quality. Any trace of moldy or otherwise spoiled food should be
completely removed. All food must be washed thoroughly.
Removal of skins from thin-skinned foods such as tomatoes and peaches is
important. A short blanching time in boiling water loosens the skins,
and a short cooling time in cold or ice water stops the cooking of the
food. Because water leaches out vitamins, dilutes color and flavor, and
results in a mushy product, do not allow foods to soak unnecessarily in
either hot or cold water.
Air is an enemy of light-colored foods, and should be kept from the
peeled or cut food. This can be done with a commercial antioxidant
(ascorbic acid), lemon juice, or a simple solution of two tablespoons
each of vinegar and salt per gallon of water. Peel or cut food directly
into such a solution for maximum protection from air. When enough food
for a canner load is prepared, drain and rinse the food for best flavor.
The packing method used is one of the most important factors in quality
canned products. Foods that are heated before being put in jars have
better quality than foods packed raw in jars. Heating destroys enzymes
and removes much of the air from food tissues.
Enzymes must be destroyed quickly for top-quality food. Removal of air
not only shrinks the food, but leads to better color, flavor and
nutrient retention, and too, fruits are less likely to float. Hot packed
jars also have higher vacuums, thus less oxidation can take place.
Tomatoes and tomato juice are less likely to separate if tomatoes are
cut and heated at once. Cutting activates enzymes in tomatoes which then
change the pectins in the tomatoes and causes separation. Heating right
after cutting inactivates the enzymes and minimizes separation.
Sugar, salt and vinegar play important roles in quality canned foods.
While sugar is not needed to safely can fruits, it contributes to better
color, flavor and texture. Likewise, vegetables may be safely canned
without salt, but when salt is used, better flavor results. Salt is
essential for slow process pickles; vinegar is needed for quick process
pickles. Canning or pickling salt should always be used. Iodized salt
will inhibit proper fermentation and react with the starch in some
foods, causing them to turn pink or blue.
Sugar concentration in sirups is important to appearance of the fruit.
With a light sirup, fruits are less likely to float than with a heavier
sirup. And with a light sirup, fewer calories are added. Then too, the
cost is less than with a medium or heavy sirup.
Headspace
Using the proper amount of headspace pays off in quality products.
Adequate headspace is needed so food has enough room for expansion
during heat sterilization.
Generally, more headspace is needed for foods heat-sterilized in a
pressure canner than those in a boiling water canner, because of
increased expansion of foods at the higher temperature.
With too little headspace, liquid is more likely to cook out of the jars
during heat sterilization. This increases the danger of seal failure due
to food particles that may be trapped at the interface of the sealing
surface. With too much headspace, air remaining in the jar can cause
darkening of the food, oxidized flavor, and lower vitamin retention,
especially in food at the top of the jar.
Pressure canning low-acid foods is receiving increased emphasis today,
mainly based on the greater safety of this technique. The method also
offers an additional advantage that is little known to home
canners—improved quality and nutrient retention.
Generally an 18° F (10° C) rise in canner temperatures increases the
destruction of bacteria tenfold. At the same time, chemical changes that
affect color, flavor, texture and nutrients of the food are only
doubled.
This means that for every 18° F (10° C) increase in canning temperature,
bacteria are destroyed five times faster than are vitamins, flavor,
color and texture. Accordingly, in contrast to boiling water canning,
heat sterilizing in a pressure canner at 240° F (116° C) (10 p.s.i.)
destroys bacteria about 17 times faster than chemical changes are
effected, accounting for better nutrient and quality retention of
pressure canned low-acid foods.
Be cautious about interpreting this as an advantage in pressure
sterilizing acid foods. This technique can increase quality and nutrient
losses because of the total time the jars of food will be near or above
boiling water temperature.
For example, with tomatoes it takes about 5 minutes until steam begins
to escape, 10 minutes to exhaust the air, about 5 minutes to build up
pressure, 5 minutes for heat sterilizing at 240° F (116° C) and 30 to 45
minutes cooling before opening the canner. That adds up to about 55 to
80 minutes at temperatures near or above 212° F (100° C), as compared to
the recommended 35 minutes for heat sterilizing in a boiling water
canner. Assuming the average product temperature is elevated above 212°
F (100° C) about half of this total time, the loss in quality could be
at least doubled.
Properly managed heat sterilization has a great deal to do with the
quality of canned food. If the temperature is too high or the time of
sterilization too long, the result is a product with poor color, soft
texture, and less flavor. Tomatoes canned in the pressure canner are an
example.
After heat sterilization, a quality canned food will have liquid
covering the solid food in the jar. The lid must allow air, but not
liquid, to escape during heat sterilization. A low liquid level in the
jar may indicate the lid did not function properly, pressure was allowed
to fluctuate in the pressure canner, or the canner wasn’t cooled
completely before opening, or raw pack was used. Foods not covered with
liquid will have poorer quality.
Jars must be air-cooled naturally after heat sterilization to maintain
quality as well as for safety. Delayed cooling in tightly enclosed
areas, such as cardboard cartons, will decrease quality of the product.
Storage conditions are vital to quality of canned foods. If stored in a
light, rather than a dark place, light-sensitive colors will darken
gradually. Some colors, such as carotenoids in tomatoes and carrots will
gradually fade with prolonged storage.
Storage temperatures between 40 to 50° F (4.5° to 10° C), if the spot is
dry, are best for quality retention. Quality losses are increased when
canned foods are stored at higher temperatures. For example, about a
third of the vitamin C is lost if foods are stored a year at
temperatures of 80° F (26° C) or higher.
Storage temperatures between 50° to 70° F (10° to 21° C) are acceptable.
Properly canned and stored foods should be safe to eat for more than two
years. However, for top quality, it is best to can only the amount to be
used in one year.
Top quality home canned foods have rich, jewel-like colors,
characteristic of the food canned. Colors are those of well-prepared
foods ready to be served, rather than fresh uncooked foods or
over-cooked foods. Light-colored foods should retain their color with no
signs of darkening at tops of jars. Fruits should look neither
under-ripe and hard, nor over-ripe and mushy. Vegetables ought to look
young and tender, rather than old and starchy. Vegetables and fruits
should be free of stems, cores, seeds, or pieces of skin, and be of
uniform size, shape and color.
Freezing
Freezing, like canning, does not improve food quality. Top quality fresh
fruits and vegetables are essential for premium frozen products. Quality
factors include a suitable variety for freezing, optimum maturity, and
freshness of the product. Even with high quality, fresh produce, it is
imperative to freeze foods on the day when they are at their peak of
maturity or ripeness for eating fresh.
Selection, sorting and trimming of produce and the quality control steps
as related to color, flavor, and nutrient retention described for
canning high quality fruits and vegetables apply equally to preservation
by freezing. However, most vegetables must be blanched before packaging
and freezing to prevent slow but accumulating effects of enzyme activity
and autoxidation. These effects, if not prevented, will cause
discoloration, oxidized flavors (sometimes described as tasting grassy
or hay-like), and increased loss of vitamins, especially A and C. Proper
blanching recommendations are contained in the USDA Home and Garden
Bulletin No. 10, _Home Freezing of Fruits and Vegetables_.
The quality of packaging materials used is reflected in overall quality
of the frozen product. Packaging materials must be moisture-vapor-proof.
This means there is no transfer of liquids or vapors from the inside to
the outside, or from the outside to the inside of the frozen packages.
In addition, fruits and vegetables must be packaged in containers with
as little air inside as possible. Air left inside will oxidize the food,
causing deterioration of color, flavor and nutrients.
Proper sealing is essential for packaging quality frozen foods. If the
seal itself is not moisture-vapor-proof, it becomes the weakest part of
the package and poorer quality results.
Adequate labeling helps assure that each package of food is used while
at top quality. Packages kept too long will be of poor quality. Even
with the finest produce and use of the best preparation and packaging
procedures, retention of quality in frozen food is affected by how
quickly food is frozen, the temperature of food stored in the freezer,
and how long it is frozen before eating.
For top quality, avoid freezing per day, more than two pounds of fresh
packaged food per cubic foot capacity of your home freezer. Food
packages to be frozen should be spread one package deep over the bottom
or other areas designated by your freezer manufacturer. The freezer
should be regulated to a uniform temperature between 0° F (-18° C) and
minus 5° F (-21° C). A freezer temperature fluctuation of more than 5° F
should be avoided if possible. Freezing too slowly, temperatures above
0° F, and temperature fluctuations in freezers increase the ice crystal
size in frozen food, lower the quality and shorten the shelf life of
food. Frozen foods should be used according to the guidelines in the
1974 Yearbook of Agriculture, Shoppers Guide.
Quality frozen fruits and vegetables should have the natural color,
texture and flavor of the individual food. There should be a minimum of
ice crystals inside the package and no sign of freezer burn.
Frozen foods should be higher in ascorbic acid and thiamin than canned
foods. Vitamin C, including that leached into the juices, approaches 90
percent of the value of raw fruits.
Drying
Quality fruits and vegetables can be sun-dried or dried inside using an
oven or a food dehydrator. As with other methods of preservation,
quality of the final product will depend greatly on quality of the fresh
food being dried. Drying does not improve the quality of any food.
A top quality dried product reflects suitable pre-treatment before
drying, and adequate drying under proper conditions. Also, appropriate
storage after drying is vital to keep moisture from re-entering the
dried product.
Fruits may be dried more easily than vegetables, because of their high
sugar content and since not as much moisture must be removed to get a
quality product. When properly dried, fruits should be leathery and
pliable, and have a color characteristic of the fruit. Excessive
darkening indicates a less desirable, poorer quality product.
Vegetables must be dried until they are brittle. The color should be
characteristic of the vegetable and not excessively dark.
To sum up, nutrient content of foods depends on natural differences,
control of deterioration, and handling techniques of food preparation as
well as preservation. Therefore, overall nutrient content of a specific
fruit or vegetable, whether fresh or preserved, may be about the same.
Top quality, garden fresh foods, served in season, provide the greatest
satisfaction when served fresh as table-ready food. Individual
preferences for market fresh, frozen canned, or dried food will differ.
Since nutrient content is nearly the same, the choice is up to the
consumer. Even more important is the choice of vegetables and fruits for
a good diet.
For Further Reading:
Food editors of Farm Journal, _How to Dry Fruits and Vegetables at
Home_, Countryside Press and Doubleday & Company (Dolphin Books),
1975. $2.95.
Hamilton, Louise W., Kuhn, Gerald D., Rugh, Karen A., with the food
editors of Farm Journal, _Home Canning—The Last Word_, Countryside
Press and Doubleday & Company (Dolphin Books), 1976. $2.95.
US. Department of Agriculture, _Home Canning of Fruits and Vegetables_,
H&G Bul. No. 8, on sale by Superintendent of Documents, U.S.
Government Printing Office, Washington, D.C. 20402. 45¢.
U.S. Department of Agriculture, _Home Freezing of Fruits and
Vegetables_, H&G Bul. No. 10, on sale by Superintendent of
Documents, U.S. Government Printing Office, Washington, D.C.
20402. 75¢.
Economics of Home Food Preservation, or Is Do-It-Yourself Back to
Stay?
_by Ruth N. Klippstein_[3]
Back-to-basics may turn out to be the theme song of the 1970’s as some
of the simple activities of the past are rediscovered and practiced.
Do-it-yourself is in. Nowhere is the trend more apparent than in the
area of home production and preservation of the family food supply. Ten
years ago no one would have dreamed the lowly canning jar lid would be
the subject of Federal hearings. No one would have believed that an
estimated one in four U.S. families would be raising and preserving a
portion of their food supply.
What motivates people to return to home food production and
preservation? Are their expectations realistic? How extensive is their
gardening? Will they continue a second year? Do they preserve any of
their crop? These were among the questions posed by Stuhlmiller, How and
Stone of Cornell University in 1975 to a group of gardeners in five
upstate New York counties.
When asked whether they gardened to save money, to have better quality
food or just for a hobby or recreation, three-fourths of the 2,800 who
replied hoped to save money, 54 percent considered gardening a hobby,
while only 46 percent gardened for fresher food. Most said they
preserved at least some of the food they grew.
If this study is indicative of the country as a whole, it is important
to realistically assess whether home food production and preservation
can save substantial amounts of money and whether the satisfaction
gained warrants the cost of time and energy expended.
The actual costs of home food preservation, for example, should be
considered. The cost of home grown food should be compared to the cost
of similar food purchased for preservation in quantities at local farms
or markets. The quality of the home preserved items should be
realistically analyzed against readily available commercially preserved
food.
There is no such thing as free food. Someone, somewhere, has to pay for
it in time, energy, know-how, and at least some outlay of dollars. Home
production in amounts needed for food preservation requires a longtime
commitment of family resources. Beginners should realize that realistic
goals and reasonable skills in the field and kitchen are essential to
make home preservation pay off.
There are no general statistics citing the average dollar-cost needed to
grow a given amount of fresh produce in a home garden. Conditions
between individual gardens, weather, soil type, skill of operator, and
geographic areas vary too much for valid comparisons.
Extension specialists at Michigan State University, however, have
computed the actual cost of raising tomatoes under home gardening
conditions in East Lansing, Mich. They found it costs 12¢ to grow the
amount of tomatoes (2½ to 3 pounds) needed for one quart, canned. A
similar cost analysis for green beans showed that beans cost 30¢ for the
amount needed for a quart. Only the expendable cost—seed, fertilizer,
pesticides and water—was considered.
Adding the expense for needed tools, hoses and other capital items
raised the cost another 33¢ a quart if the cost were absorbed in one
season or 2¢ if amortized over a 20-year period. Unfortunately, the
first-year gardener will find that the outlay for tools must be spent
the first year so that return for the investment requires a commitment
to gardening over many years.
Additional expenses are necessary if the bounty is to be preserved at
home. Equipment for preserving tomatoes is minimal but equipment for
canning vegetables and for freezing may be costly. Homemakers needing to
invest in canners, a pressure canner, and home freezer will find that
the dollar cost per package of food preserved during the first years of
preservation may be higher than the cost of comparable food at the
corner supermarket.
The costs of canning peaches, tomatoes and green beans in upstate New
York were calculated by the author in 1975 and updated for price changes
in 1976 using a number of different cost variables. She found that those
who canned tomatoes could realize substantial savings, while the cost of
purchasing peaches and preserving them at home approximated the cost of
the commercially canned peach.
Determinations of the true cost of frozen food must consider the initial
cost of the freezer plus the cost of operation and repair. Containers,
plastic bags and boxes, or foil are additional costs.
Evelyn Johnson in her Outlook Talk of 1975 quoted staff at Virginia
Polytechnic Institute and Cornell University as reporting a cost of 20¢
to 24¢ per pound of food frozen just for the convenience of freezing and
storing food at home. Add to this the price of the food being frozen for
the correct cost of home-preserved frozen food.
Freezing is probably the most satisfactory method of home food
preservation, the most versatile and the easiest to do. But for all
except the very best managers who use the freezer intensively, the home
freezer is more a convenience than a money saver.
[Illustration: Needed equipment for home canning. Left, water bath
canner, and right, pressure canner.]
Time, Energy Costs
Raising a garden takes time over a significant number of months. As a
hobby for table use, gardening can be a real pleasure. Skillful persons
with the right tools and know-how can handle a garden of the size needed
for home food preservation with a few hours of work a week, once the
plants are well established. Novices can expect to spend a significantly
greater amount of time per week during the four or five month growing
season in northern areas and even more in areas with longer growing
seasons.
The author, an experienced gardener, kept records of the hours spent
cultivating and harvesting a 20 by 40-foot garden, planted primarily for
fresh consumption. Only three foods—tomatoes, green beans and
cucumbers—were raised in amounts sufficient for a limited amount of home
preservation. Over 40 person-hours were required. The actual grocery
store value of the garden food consumed by the family of three was $45.
Food given as gifts and preserved raised the dollar value to $75.
Gardening often helps stretch cash income, but the dollar return is low
for hours of effort. And poor weather may cause crop failures and small
yields, regardless of effort. Food preservation also is time-consuming.
_Satisfactions._ Why garden or preserve food at home? Most gardeners
will cite a number of reasons:
—The best of good fresh food with no unknown additives or ingredients
—Healthy exercise
—Family pleasure working together toward a goal
—The joy of giving
—The challenge of growing a seed into edible food
—Prestige
Cost of Home Food Preservation
Energy
Method Time Fuel Human Dollar Quality
effort cost from satisfaction
kitchen to
table
Freezing Minimal High Low Very high Very high
low
Canning Moderate Moderate High Moderate Moderate to
high
Drying High Moderate Moderate Moderate High
to high to high (specialty
items)
Low, if
only method
available
Pickling High Low Moderate []Depends High
upon type
chosen
Storage Low to Low Moderate Low Moderate to
(Unprocessed) moderate (Checking/ high
culling)
[A]Some (such as quick dill pickles) are quick to make, take little
effort, and use inexpensive ingredients. Others require prolonged
brining over several days’ time plus expensive sugar and other
ingredients.
There is no one right answer to the question, “Does it pay to raise and
preserve my own food?” It depends upon your personal goals. You may not
save a significant number of dollars. You will work hard. And you
probably will experience one of the most exciting activities
possible—raising at least some of the food your family uses.
“We grew it” are heady words which bring people back to home food
production and preservation year after year.
Beginner’s Guide to Home Canning
_by Frances Reasonover_[4]
Canning is probably the most economical and practical method of
preserving food at home. Among other things it is a way to save food
that otherwise might be wasted.
Cost of home canning depends on the kinds and sources of food canned as
well as the processing methods, containers, and equipment used. Other
cost factors—labor, energy, water and added ingredients—make exact cost
figures impossible to apply generally, but studies are reporting
averages that show canning to be economical.
The wise homemaker will can only the amount to be used within a year.
Food held longer will be safe to eat if it has a good seal and no signs
of spoilage, but there may be nutrient or quality loss, especially if
stored at temperatures above 70° F.
As a beginner canner you need to know something about micro-organisms,
including yeasts, molds and bacteria, on the food, in water, air and
soil, as causes of spoilage in foods. Knowing about these minute forms
of life, which are so abundant everywhere, will help make the work safer
as well as more interesting.
In addition to the action of these minute organisms, the spoiling of
fruits and vegetables is hastened by natural changes in color, flavor
and texture of the food. These changes result from the action of enzymes
or micro-organisms found in nature which break down and decompose
foodstuffs.
Bacteria are the most serious foes to combat in canning because they are
more difficult to kill by heat than either molds or yeasts.
Acid in canned food is expressed as pH value. Foods having a pH of 4.5
or lower are called high-acid foods and those with a value of 4.6 or
higher are termed low-acid foods.
Since few bacteria thrive in acids, their destruction is less difficult
in fruits than in vegetables (with the exception of tomatoes).
Botulism is a deadly poison caused by a toxin from the growth of spores
(seeds) of the bacteria, _Clostridium botulinum_. These spores will
produce a deadly toxin in low-acid foods in the absence of air (oxygen)
inside a sealed jar. Therefore, the spores must be destroyed by
processing under pressure at 240° F. The length of time has been
determined by scientists for each individual food.
_Clostridium botulinum_ will not grow in foods with a pH of 4.5 or
lower, so high-acid foods may be processed safely in boiling water at
212° F.
Low and High Acid Foods
Low-acid vegetables
Asparagus
Beans—snap or shelled
Beets
Carrots
Corn
Potatoes
Pumpkin
Squash
Sweet potatoes
High-acid fruits and vegetables
Apples
Apricots
Berries
Cherries
Grapefruit
Peaches
Pineapple
Rhubarb
Tomatoes
Yeasts, mold and non-spore forming bacteria are readily controlled by
processing at 212° F.
Most canning equipment and supplies may be purchased at hardware stores,
housewares departments, and from mail order companies. Jars and lids are
available in many retail stores.
Canning Jars
Select standard canning jars made of tempered glass that can withstand
high temperatures. The manufacturer’s name or symbol in glass will
identify the product. With careful handling, jars last an average of
about 10 years. Avoid using antique jars because there can be hair-line
cracks not visible to the eye, causing jars to break.
Use canning jars in sizes suitable for the product canned and your
family’s needs. Canning jars generally are sold in half-pint, pint and
quart sizes with wide and narrow mouths. Large-mouth jars are convenient
for packing such foods as whole tomatoes and peach halves. Quart jars
are convenient for vegetables and fruits where your family has four or
more members.
Examine the sealing edge of jars for nicks, cracks, or sharp edges that
would prevent a seal. Discard any with these imperfections.
One-trip jars from purchased canned foods should not be used because
they generally are not tempered to withstand the high heat required for
home canning, and may break when subjected to the heat. Tops of these
jars may not fit standard canning lids, thus preventing a good seal.
[Illustration: Home canning equipment.]
_Closures_—jar lids and rings come with new canning jars. The sealing
compound of lids recommended for one use only will not hold a seal
effectively after the first use.
Select lids appropriate for the jars being used. You may find the
two-piece units (flat lid with sealing composition and ring), one-piece
lids, or flats with separate gaskets made of metal or plastic. Always
follow the instructions for pretreatment as indicated on the box or
container by the manufacturer. If no name is indicated on the lid, use a
black wax marking pencil or crayon and mark the identity on each lid. If
there are problems, contact the manufacturer whose name and address is
on the box or container.
Screw ring bands may be reused if kept clean and dry in a protective
container with a tight-fitting lid. Never use bands with rust, or pried
up or bent edges.
If you have extra lids, store them protected in a dry, cool place.
One-piece zinc caps lined with white porcelain, with rubber rings, may
be used. The caps may be reused if they have not cracked, spread or bent
at the edges and are clean, like new. The rubber rings are effective
only once because they tend to dry and deteriorate with age, often
become porous, and sometimes crack.
If you have jars with bail wire clamps, sometimes called
“lightning”-type jars, be sure they are not in the “antique” class. Lids
for these jars are all glass, and rubber rings are used between the jar
and lid for sealing. A wire clamp holds the lid in place during
processing; after processing, the short spring wire of the clamp is
snapped down to complete the seal.
A _boiling water bath canner_ is needed for processing high-acid foods,
such as fruits, tomatoes, tomato and fruit juice, and pickles.
Water bath canners in several sizes are available on the market. The
container must be deep enough for a rack to hold the jars off the bottom
of the canner. The depth allows water to be over the jars of food by at
least 1 to 2 inches. Keep 1 to 2 inches of space above the water to
allow for boiling; this prevents water from boiling over.
The canner must have a tight-fitting lid. Or you can use a large kettle
with a tight-fitting lid, and a wooden or wire rack to hold jars off the
bottom. There should be free circulation of water to every part of the
surface of the jar and lid.
If you are going to buy a water bath canner, check the height, and the
lid to be sure it is tight-fitting. The rack preferably should have
dividers so jars will not touch each other or fall against the sides of
the canner or each other during processing.
A _steam pressure canner_ is absolutely essential in canning low-acid
foods, such as vegetables, and insures the destruction of spoilage
micro-organisms.
Ten pounds pressure is used for processing food in standard canning jars
at sea level. This pressure corresponds to 240° F.
The steam pressure canner is made of heavy metal that withstands high
pressure developed by steam. It consists of a kettle with a
tight-fitting lid equipped with an accurate weight or dial gage to
register the pounds of pressure in the canner. The lid must lock or seal
to prevent escape of steam.
The canner must have a safety valve, petcock or steam vent that can be
opened or closed to permit exhausting (venting), and a pressure gage. It
must have a rack to hold jars at least ½ inch from the bottom of the
canner.
A dial gage indicates pressure on a numbered instrument.
A weighted gage has no dial, but automatically limits pressure with
weights preset for 5, 10, and 15 pounds pressure.
[Illustration: Scalding tomatoes in a blancher.]
The pressure is adjusted for high altitude. For information on canning
at altitudes above sea level, see the later chapter by Carole Davis.
To insure the canner’s proper working condition, check the dial gage for
accuracy each year—or if a canner or lid has been roughly handled or
dropped, the dial gage glass broken, or any parts are rusty. The
manufacturer or your county Extension office can give information on
testing availability. Study and follow the manufacturer’s directions for
using your pressure canner.
Run through the process of operating the pressure canner on your range
in a trial run before you get into the canning season, to be sure
everything is working properly. Make a note of the dial setting of the
range if you use an electric range for holding pressure steady.
Trying to use a pressure canner obtained from garage, rummage, or
auction sales or handed down to you from someone’s attic may prove
dangerous. You may not have any idea as to the care, handling, or
storage of the canner. A manufacturer manual on care, use and
replaceable parts usually is not available. Old-old canners did not have
complete information—manufacturer’s name, address or model number—on the
appliance.
General kitchen equipment is helpful in any needed washing, peeling,
coring and slicing in the preparation of fruits and vegetables. Examples
are, a vegetable brush for cleaning vegetables, a blancher or wire
basket for scalding fruits and vegetables such as tomatoes and peaches
to loosen skins for peeling, and a colander for washing delicate fruits
such as berries.
A food mill is handy for making purees and straining fruits for making
juices, and a strainer for straining juice. A long handled fork or
plastic spatula aids in fitting and packing food and removing air
bubbles. A wide-mouth funnel is very convenient for filling jars, and a
jar lifter helps you avoid burns in handling hot jars. Use an automatic
timer to time processing accurately.
The number of pints of preserved food you will get from a given quantity
of fresh food depends on the quality, variety, and maturity of the fruit
or vegetable; on the size of the pieces, and on the packing method used.
Selection of good sound fruits and vegetables is of paramount
importance. The quality of canned fruits and vegetables will be no
better than quality of the raw food used. For best flavor retention,
preserve only those vegetables that are young, tender, and freshly
gathered.
Work Fast
All steps, from beginning to end, of any lot of canning should be
carried through as rapidly as possible. A good slogan is “two hours from
harvest to container”.
Work fast with small amounts of food at a time, especially vegetables
with high starch content such as corn and peas which lose quality
rapidly. Any delay will result in loss of flavor and nutritive value.
Sorting and grading should be done very carefully, according to size and
degree of maturity and ripeness.
Use only uniformly well-ripened products. Discard all defective products
and use together those of the same size.
Dirt in seeds, bits of food, or sirup contains bacteria that is hardest
to kill, and encourages yeasts and molds to grow on the outer surfaces.
Wash fruits and vegetables thoroughly before canning.
Scalding, peeling and coring—some fruits, such as peaches and tomatoes,
are scalded in order to peel them smoothly.
Follow up-to-date recommendations, available in U.S. Department of
Agriculture or Extension publications, for detailed procedures in
preparing fruits and vegetables for canning.
Packing Methods
You can pack food hot or raw in jars. Hot-packed food is heated
thoroughly before it is packed into jars. Raw-packed food is placed raw
in jars. Watery and soft foods such as tomatoes are pressed gently to
make their own juice.
Air, a poor conductor of heat, should be removed from the jar. Remove
air bubbles by gently moving the blade of a plastic spatula or plastic
knife around the jar—being careful that the food is not broken. Add more
boiling liquid if necessary to get a proper fill.
When filling jars, you will find the jar-filling funnel easy to manage.
This makes it possible to avoid spills of seeds, bits of food, or sirup
that could prevent sealing. But even when using a funnel you still need
to wipe the jar rim.
[Illustration: Heating beans thoroughly before placing them in jars.
Here, cut beans are covered with water to be followed by five
minutes of boiling.]
Prepare the lids and sealing of jar according to the manufacturer’s
directions. When using a flat metal lid, place the composition side on
the rim of the jar. Add the ring band and screw it down until firm, but
not hard enough to cut through the sealing compound. The lid will have
enough “give” to let air escape during processing. This is called
venting and means heating to remove air from jars.
When using porcelain-lined zinc caps, fit the wet rubber ring on the jar
shoulder, but do not stretch it more than necessary. Screw the cap
firmly and turn it back ¼ inch.
Use a jar lifter or tongs and place the filled jars on the rack in the
canner. Fill and place jars in the canner one at a time to keep jars as
hot as possible while filling the canner.
Water Bath
Before you begin preparing the food, fill the water bath canner half
full of hot water. This permits water to heat while you prepare the
food. Put a large kettle or teakettle of water on to boil. The water
should be boiling when hot-pack food is put into the canner.
Place raw-pack jars in water that is hot (180° to 190° F), just below
boiling. Then bring it to a boil after adding jars.
As the rack of jars is lowered into the water, the water level will
rise. If more water is needed to have the jars completely covered by 2
inches of water, add boiling water.
Prepare only enough jars of food at one time to fill the canner. Work
rapidly, allowing as little time as possible between filling and closing
the jars and getting them into the canner.
Start counting processing time as soon as the water in the canner
reaches a gently rolling boil. Put the lid on the canner. Set your timer
or clock and make a written note of starting time and final time. Keep
the water boiling all during the processing period. If water boils down,
add boiling water sufficient to keep it at the required height. When
pouring water, avoid letting it hit tops of the jars.
Process for the recommended length of time. Do not cut processing time.
Pressure Canner
Follow the manufacturer’s directions for operation of your pressure
canner before, during and following processing. Supplement these
directions with information in U.S. Department of Agriculture or
Extension publications.
Count processing time as soon as the pressure reaches 10 pounds or the
proper pressure adjusted for altitude. Be sure to hold pressure steady.
At end of the processing time, remove the canner from the heat. Allow
the canner to cool until the gage registers zero to avoid breakage of
jars and loss of liquid from jars. After a minute or two, open the
petcock gradually and remove the cover. If a weighted gage is used,
nudge the weight slightly. If no steam escapes, pressure is down. Tilt
the far side of the lid upward so steam escapes away from your hands and
face. Because food in the jars may be boiling vigorously, leave jars in
the canner about five minutes and then remove them.
After Processing
When you remove hot jars from the canner, use a jar lifter, or protect
your hands with cooking mits, pot holders or canvas gloves. Set the jars
upright to cool on a rack, such as a cake rack, or a bread or cutting
board, with double layers of dry cloth or newspapers beneath the jars.
If jars are placed on a cold surface or wet cloth, the difference in
temperatures may cause the glass to crack.
Avoid placing jars in a draft, but leave two or three inches between
them so air can circulate freely. Avoid further tightening of lids that
have sealing compound, since this usually breaks the seal—unless the lid
manufacturer states it is safe to tighten.
If your processing temperature was not held steady and liquid boiled out
in processing, do not open the jar to add more. Leave the sealed jar
just as it is.
Do not cover jars because this slows down cooling and food continues to
cook. If you have an air conditioning vent that will direct cold air on
jars, cover the vent during this canning session.
After 12 hours, check the seals. The vacuum may cause a loud snap of the
two-piece vacuum seal while it cools, which is an indicator of an
airtight seal. If the center of the lid holds down when pressed and the
lid does not move, it is sealed.
Tap the center of the lid with a spoon—a clear, ringing sound indicates
a good seal; a thudding sound indicates the possibility of an imperfect
seal.
If there is a sealing failure, you will need to reprocess the jars.
Remove the lid, heat the food and liquid, fill a clean jar and use a new
lid. Process the full length of time. If only a few jars did not seal,
you may elect to refrigerate and use the food within a day or two or
freeze it.
Once the jar is sealed, allow it to set until cold. Then remove the
screw ring band, wash and store in a dry place for reuse. For safety
make a routine check of canned foods each month.
Label and Inventory
Write name of product and date canned on a gummed label or the lid of
each jar with a felt tip pen. Keep a record of food canned, date, number
of quarts or pints, and a place for you to check them off as you use
them. This can be your guide for next year’s preservation plan. Use food
preserved for the current year, readying a storage place for next
season’s garden produce.
Canned foods stored in a dry, dark, cool temperature (70° F or below)
will retain good eating quality for a year. Home canned foods stored in
a warm place near direct sunlight, hot pipes, above a range or
refrigerator, or in kitchen cabinets may lose some eating quality within
a few weeks. Dampness may corrode lids and cause leakage so that the
food spoils.
The main cause of spoilage in canned foods is improper processing.
Bulging jar lids, or a leak, may mean gas is present and the food
spoiled.
Before opening home canned foods, wash jars and lids and carefully
inspect the jars. Bacteria, yeasts and molds should have been destroyed
if the food was properly processed.
When you open the container, look for such danger signs as spurting,
cloudy or frothy liquid, an “off” odor, deterioration, or slimy texture.
A foamy or murky appearance and patches of mold are visible signs of
spoilage. That ordinary looking mold on home-canned food may indicate
the presence of a much more deadly problem: botulism.
[Illustration: ALWAYS _label home-canned foods_.]
Destroy food if any of these signs are obvious; discard out of reach of
humans and animals.
The odor in good jars of food should be pleasant and characteristic of
the product. Do not use food which looks or smells bad, or if there is
any doubt as to its safety.
All low-acid, home-canned food should be boiled 10 to 20 minutes to
insure destruction of botulism-causing toxin for added safety. Heating
denatures the toxin so that it does not react with the body. Never taste
home canned food before cooking it.
Successful results largely depend upon the accuracy with which
up-to-date directions are followed.
Safety is best assured when you exercise special care as you prepare and
pack food into canning jars, fitting jars with properly pretreated lids,
and heating jars of food to a high enough temperature for a sufficient
length of time to kill micro-organisms that cause spoilage.
A Primer on Home Freezing for the Beginner
_by Charlotte M. Dunn_[5]
Every homemaker knows that meals must be planned to get the most out of
the food dollar and to provide the family with a well-balanced diet. The
freezer, more than any other household appliance, can help secure these
results. The more you learn how to use it in relation to your own
family, the greater the returns.
Freezing is a quick, convenient and easy way to preserve foods in the
home. Plan ahead to manage your time and energy for preserving food
directly from harvest. Freeze limited amounts at one time so the work is
spread over several days of picking, rather than squeezed into one long
tiring period of time. Be practical about what you attempt.
Your own observation has taught you that some foods “spoil” more quickly
than others, so the rate of speed at which they must be frozen varies
with their individual temperaments. A good rule for home freezing is:
two hours from garden or orchard to container, and the faster the
better!
Most food that is highly perishable at normal temperatures can be quick
frozen. Even delicate fruits and vegetables can be frozen, with only a
few exceptions such as tomatoes (stewed tomatoes can be frozen) and
those vegetables that lose crispness such as radishes, celery, cucumbers
and salad greens.
Decide what you will freeze on the basis of availability of foods,
family needs and taste, freezer space, cost of freezer storage, and
availability of alternate methods of storage.
It is essential to start with high quality raw material. As garden foods
mature, process without delay. Quality of the frozen food will be only
as good as the quality of the food before freezing. Freeze foods at
their peak of eating quality to preserve flavor, texture, and appearance
as near those of the fresh product as possible.
Do not ignore details of the recommended procedures for preparing foods
for freezing. Seemingly unimportant steps can make the difference
between a low quality and a superior frozen product.
Before you begin freezing foods at home it’s important to know exactly
which process to use and what the process is doing to the food.
Micro-organisms grow on food, causing it to spoil. The common growths
are simple yeasts, molds, and bacteria. Because these micro-organisms
are everywhere—in the air, water, soil and on all surfaces they
contact—they naturally occur on all foods. Storing and preserving foods
properly controls or inhibits the growth of micro-organisms, thus
maintaining both quality and safety of the food.
Cleanliness and sanitary methods are as important in handling foods for
freezing as in preparing them for immediate use.
All foods contain chemical substances called enzymes. They are essential
to life, and continue their chemical activity after the fruits and
vegetables mature or are harvested.
If allowed to work after a food reaches its peak of maturity, enzymes
destroy the food’s physical properties, thus changing its color, flavor
and texture.
When perishable food is not preserved by one of the recommended ways,
enzymes within the cells of the food continue to live and cause
spoilage.
What Freezing Does
Freezing and storage even at very low temperatures will not inactivate
any of the common enzymes. At 0° F, the recommended temperature for
storing frozen foods, enzymes are not inactivated but only slowed down.
In two to three months they will produce off-odors and bad taste. This
temperature only checks the growth and reproduction of destructive
bacteria. The faster a food is properly prepared frozen, the sooner both
enzymes and bacteria are rendered harmless.
Just about every kind of food you or I will freeze contains moisture or
water, and the process of freezing food involves the freezing point of
water. As temperature of the surrounding air goes below the freezing
point of water, the water progressively crystallizes out in the form of
pure ice. Size of the crystals which form is determined by the span of
time during which freezing takes place. When the temperature is lowered
slowly, the crystals expand considerably. If the freezing is sharp and
sudden, the crystals retain approximately the same size as the original
water molecules.
In case you have doubts about how well a food will freeze, test it
before freezing large quantities. To test, freeze three or four packages
and sample the food a couple of weeks later. This will show the effect
of freezing but not the effect of storage. Some varieties of the same
kind of food freeze well, others do not.
Much of the success you have with your home freezer will depend on how
you prepare, package, wrap and seal foods. Protecting frozen food is as
important as freezing food of high quality.
You will need general kitchen utensils plus a steel, aluminum or enamel
kettle large enough to hold at least one gallon of boiling water, with a
tight fitting cover. Use a mesh basket, a strainer, or large squares of
cheesecloth to hold one pound of vegetables in the boiling water.
Steaming of cut, sliced or green leafy vegetables is recommended and
will preserve more nutrients than water does.
You will need a container to hold ice water for quick chilling of
vegetables to stop cooking action. Drain thoroughly in a colander and
turn out on absorbent towels.
It is false economy to skimp on wrappings and containers. They should
protect the food from cold air, which is dry, so as to retain the
moisture in foods and prevent freeze burn and dehydration. Select them
according to the use they will be put to.
Most freezer containers on the market today are easy to seal,
waterproof, and give satisfactory results. Rigid plastic containers,
bags, and jars with wide tops are favorites.
Moisture- and vapor-resistant wraps, which are exceptionally effective
at excluding oxygen, include heavyweight aluminum foil, coated and
laminated papers, polyethylene films, saran, and polyester films. They
should be strong and pliable so the wrap will adhere readily to
irregularly shaped objects, and eliminate as much air as possible to
avoid frost accumulation inside. Careful wrapping is of no avail if the
package breaks. It should be easily sealed, either by heatsealing or
freezer tape.
Freezer bags are available, and freeze-and-cook bags that withstand
temperatures from below 0° F. to above the boiling point. The
freeze-and-cook bags are suitable for freezing and reheating food.
Points to consider include the size convenient for your use and the
cost.
Materials not moisture-proof and vapor-proof, and thus not suitable for
packaging foods to be frozen, are ordinary waxed papers, cartons from
ice cream or milk, and plastic cartons from cottage cheese or gelatin
products because they crack easily.
Compare price, durability, shape and reusability in selecting
containers, keeping in mind their convenience and the economical use of
freezer space.
Retaining the vitamins and other nutrients depends on how fruits and
vegetables are handled before freezing, on storage temperature in the
freezer, and on how you cook them. Always follow up-to-date
recommendations available from the U.S. Department of Agriculture or
county Extension office.
Select foods of top quality. A freezer is not magic—it does not improve
food. Its function is to preserve quality and food values and to prevent
spoilage.
Choose vegetables and fruits suitable for freezing, and the best
varieties for freezing. Because growing conditions and varieties vary
greatly across the country, check with your county Extension office to
find out which varieties are best for freezing.
Freeze fruits and vegetables when they are at their best for table use.
If possible, freeze those that are ripened on the tree, vine or bush.
Fruits should be ripe but firm.
Enzymatic changes continue after harvest, lowering quality and nutritive
value. If stored at too warm temperatures, fruits can lose vitamin C,
turn brown, lose flavor and color, and toughen.
Don’t delay in harvesting vegetables since asparagus, corn, peas, snap
beans, and lima beans all deteriorate rapidly in the garden after
reaching their peak.
Observe cleanliness while you work, to avoid contaminating foods.
Prepare vegetables for freezing by blanching them in boiling water for
recommended times. County Extension offices will have information on
specific times for various foods.
Blanching vegetables is absolutely necessary to inactivate enzymes that
cause undesirable changes in flavor and texture. This brief heat
treatment reduces the number of micro-organisms on the food, enhances
the green color in vegetables such as peas, broccoli and spinach, and
displaces air trapped in the tissues.
Pack food in containers as solidly as possible to avoid air pockets,
leaving the necessary head space for expansion. Press out as much air as
possible, with your hands or by using a freezer pump. Then seal the
plastic bags by twisting the open end, folding it over. Freezer rubber
bands, twist-seals, or freezer tape are satisfactory for sealing bags.
Label packages clearly and carefully with name of product, date when
frozen, number of servings or poundage, and any information that will
help you. Special pens are made for marking frozen food products. Or you
can use a wax pencil or crayon.
Speed is important in preparing food and getting it into the freezer, so
as to maintain quality. Put only the amount of unfrozen foods into the
freezer at one time that will sharp freeze within 24 hours.
Allow at least one inch between packages of unfrozen food in the freezer
for circulation of cold air. Leave packages in freezing position for 24
hours before stacking them close together.
Uniform freezing temperature and keeping frozen products at 0° F or
lower will maintain quality. Different foods have varying storage
periods, so keep your frozen food inventory changing.
Use a freezer thermometer in your freezer. Check your freezer door and
wall plug daily to avoid any catastrophe.
A freezer can pay wonderful dividends with considerable thought and
planning by the homemaker.
Pressure Canners, Vital for Low-Acid Foods
_by Nadine Fortna Tope_[6]
Use of a pressure canner for preserving low-acid foods is not new.
Pressure canners for home canning were first marketed in the early
1900’s. In 1917, the U. S. Department of Agriculture announced that use
of a pressure canner at 10 pounds pressure (240° F) was the only safe
method for canning vegetables. Today’s recommendations are essentially
the same.
A temperature of 240° F or 10 pounds pressure at sea level is needed to
kill spoilage organisms in a reasonable time, especially the spores of
_Clostridium botulinum_. These spores, if not killed, can produce the
most deadly toxin known to man.
The commercial canning industry stringently follows safe canning
practices. Their safety record is excellent. _A Complete Course in
Canning_ by Lopez (1975) says that since 1925 four deaths have been
reported from the consumption of more than 800 billion cans of
commercially processed foods. The record for home canning is much
worse—450 deaths in a fraction of the number of cans. Unsafe practices
were probably used in preserving the deadly home-canned food.
Methods like open kettle, oven, and boiling water bath canning for
low-acid foods are not sufficient to kill _Clostridium botulinum_
spores. Educators talk to many people even today who still use unsafe
practices because “that’s the way my mother always did it”, or because
they are unfamiliar with pressure canners.
In this chapter, the need for safe pressure canning procedures will be
discussed along with the rationale for using care in preparing low-acid
foods for canning.
Acidity of a particular food is the most important factor in determining
which canning method should be used—pressure or boiling water bath.
Acidity is measured and stated much the same way we express length or
weight. Acidity (pH) refers to acid strength, not the amount of acid
present.
For example, citric acid, an acid found in oranges, grapefruit, and
other citrus fruits, is a weak acid compared to hydrochloric acid, a
very strong acid. The measure used to express acid strength is pH. The
pH scale runs from 1 to 14 with 7 as the neutral point. Substances with
pH below 7 are called acidic, while those above 7 are called basic or
alkaline foods. The lower the pH, the more acid the food.
Acidity or pH of a food affects the length of time it must be processed
at a particular temperature to make it safe. The more acid the food (the
lower the pH), the shorter the time required for processing.
Almost all foods are acid in nature. Hominy is an example of a food that
is neutral or slightly alkaline.
Foods are further categorized as high acid or low acid because the _C.
botulinum_ spore will not grow at pH levels of 4.6 or below. High acid
foods (pH 4.6 or below) include tomatoes and all fruits except figs.
(See chart).
Those with a pH above 4.6 are the low-acid foods. All vegetables except
tomatoes and those that have been pickled or fermented are low-acid.
Safe processing times have been established at 240° F for low-acid home
canned products, since at this temperature the processing times are
reasonably short and texture of the resulting product remains good. The
heat-resistant _C. botulinum_ spore has been known to survive many hours
of boiling at 212°. Once food reaches 240°, the spore is killed when
held for the recommended number of minutes.
Fruit and Vegetable Acidity
High acid foods
Lemon Juice
Cranberry Sauce
Gooseberries
Rhubarb, Dill Pickles
Blackberries
Applesauce, Strawberries
Peaches
Raspberries, Sauerkraut
Blueberries
Sweet Cherries, Apricot
Tomatoes
Low acid foods
Figs, Pimentos
Pumpkins
Cucumbers
Turnips, Cabbage, Squash
Parsnips, Beets, Green Beans
Sweet Potatoes
Spinach
Asparagus, Cauliflower
Carrots
Potatoes
Peas
Corn
Holding of produce to be canned for long periods in warm summer
temperatures gives bacteria ample time to multiply into vast numbers,
thus increasing the chances of spoilage.
For example, one cell can multiply into a billion cells in just 15 hours
of holding under favorable conditions.
Salt and spices added to low-acid canned products in amounts recommended
do not appreciably alter processing time. Salt may slightly lower the
heat resistance of some micro-organisms but not enough to present a
problem if omitted for dietary reasons.
Fats and oils, if added, may reduce the rate of destruction of bacterial
spores. Spores of _C. botulinum_ have been known to survive beyond all
reasonable expectation when heated in oil suspensions. Thus, adding oil
or fat to a product being canned could be dangerous and is not
recommended.
The type, consistency, and piece size of food and how it is packed in
the jars are important factors which affect processing time. In
preparing jars of food for the pressure canner, follow directions
carefully. Do not use jars larger than the directions specify.
Determining the safe processing time for a food product involves two
important steps.
First, the rate of heat penetration is measured by finding the spot in
the jar that takes the longest time to heat. This is referred to as the
“cold spot”. Times will depend on the type of food (squash vs tomato
juice) as well as how it is prepared (whole kernel vs cream style corn).
The second step is done in a laboratory. A known amount of some live
bacterial spores is put into the “cold spot” of the jar of food. These
jars are then heated and the amount of time needed to kill the spores is
determined.
How Food Is Heated
Heat is a form of energy which flows from hot to cold substances. This
flow occurs by convection, conduction, and radiation. In a pressure
canner, convection and conduction are the primary methods of heat
transfer.
Convection heating occurs in thin liquids and in gases like air and
steam. As molecules are heated, they become lighter and rise to the top
of the jar, displacing cooler ones toward the bottom. This movement is
visible in water that is being heated in a clear glass container.
Convection heating occurs best in liquids like fruit and vegetable
juices or broths. These heat rapidly and thus have shorter processing
times.
Small quantities of starch either added or leached from vegetables slows
down the convection and increases processing time. For example, jars of
liquid containing pieces of green beans or peas would heat more slowly
than apple juice because the pieces would interfere with convection.
A tightly packed jar takes longer to heat than a loosely packed one
which allows some convection heating. Thus it is important not to
over-pack jars as this will decrease the rate of heat penetration.
Some types of food heat by a combination of conduction and convection.
One example is a peach half in thin sirup. The sirup heats by convection
while the peach heats by conduction. Another example is cream style
corn. Initially, the liquid is thin and heats by convection. As the
liquid thickens, it heats by conduction.
Conduction occurs when heat is transferred from one particle or
substance to another right next to it. This is the slowest type of heat
transfer. Foods that mat together, like spinach, or viscous material
like mashed pumpkin, heat by conduction. The larger the pieces of food
or the thicker the puree, the slower the heat penetration.
Pressure Canners
A pressure canner is a kettle made from a material, usually aluminum,
that is strong enough to safely withstand the pressures used in home
canning. The lid is built so it can be locked to the base of the canner.
On one type, metal in the sealing edge is ground smooth so little or no
leakage occurs between the lid and the base. Care should be taken to
avoid damage to the sealing surfaces which could ruin the canner.
Other canners have a gasket made of a rubber-like substance that
prevents leakage of steam. The gasket should be washed in hot suds,
rinsed, and dried thoroughly after use.
All pressure canners include a safety plug or fuse. One type has a metal
fuse that melts when the temperature is too high. If the canner is used
properly the fuse should never need replacing. Another type of canner
has a rubber-like safety plug. Care should be taken to replace the plug
when the rubber gets hard. As the rubber hardens, it takes a greater
pressure for it to blow out. Some older type canners have a petcock that
serves as a vent and safety valve.
In canners that have a pressure gage, vents serve to exhaust air from
the canner. The air is exhausted by venting for 10 minutes after steam
starts escaping. All the air must be exhausted before the canner is
sealed because the steam has much more heat energy. For example, air in
a 212° F oven feels just warm while 212° steam from a teakettle will
burn you.
Be sure to read and follow the instructions with your canner.
All canners should have some type of rack in the bottom. A rack keeps
the jars from touching the bottom of the canner and breaking. It also
aids in transferring the heat more evenly within the canner by
permitting water and steam circulation.
There must be enough water in the canner to provide steam throughout
processing. Two quarts of water is usually recommended, although this
may vary depending on size of the canner and the quantity of jars.
Pressure canners have either a dial gage, a pressure control or a
combination of these. The dial pressure gage indicates the pressure and
corresponding sea level temperature. The control type canner has a
precision weight that sits on the vent pipe and jiggles to regulate
pressure. A third type is a combination gage and control.
The dial pressure gage measures steam pressure. The tube in the pressure
canner gage operates like a New Year’s Eve noisemaker, which is a flat
paper tube rolled up. Blowing into the tube causes it to become more
round and unroll.
The pressure gage works the same way except not as dramatically. The
gage is made of a partially flattened metal tube. When pressure is
applied, the tube becomes more round and straightens slightly. The
needle [pointer] moves as the tube straightens. The gage is calibrated
to indicate pressure. Pressure is controlled by adjusting burner heat to
maintain the desired pressure. This type of gage should be checked
yearly or after suspected damage, such as dropping, to be sure it
functions properly.
A pressure control consists of a precision weight that rests on a
specially designed vent pipe. It automatically maintains an even
pressure and temperature inside the canner. Pressure builds inside the
canner until the upward force (steam pressure times seat area) is
greater than the downward force of the weight on the seat area. At this
point, the control weight is lifted, releasing steam and reducing
pressure, until the upward force equals the weight. The pressure inside
again increases slightly, lifts the weight, and releases the pressure.
The repeated lifting and reseating or jiggling of the control weight
indicates that the pressure is being controlled.
The burner is adjusted so the control jiggles at least several times a
minute. Excessive jiggling will deplete the supply of water in the
canner.
There are two types of pressure controls. One type is a single weight
with 3 holes which fit on the vent pipe. The diameter at the base of the
hole (seat area) is different for each of the 3 pressures—largest for 5
pounds pressure, and smallest for 15 pounds pressure.
The second type has 1 seat area and a 3-piece weight. For 5 pounds
pressure, the small center weight is used. One additional ring or weight
is added for 10 pounds pressure, and a second ring or weight is added
for 15 pounds pressure.
With care, the pressure control remains accurate throughout the canner’s
lifetime. Be sure that seat areas where the weight and the vent pipe
make contact are not damaged or excessively worn; this could affect the
canner’s performance.
The combination gage is not as common as the other two types. It has a
sliding piston which pushes up on a spring. As pressure inside the
canner increases, the piston is pushed up. Rings on the piston indicate
pressure. If the heat is not regulated correctly, pressure builds up to
beyond 15 pounds, at which point the weight is lifted to release the
excess pressure. It will jiggle audibly, indicating to the user that the
pressure is too high. This system serves as a gage as well as a safety
device.
The combination gage should be kept clean and dry when not in use, to
prevent corrosion. It also must be checked yearly to be sure the piston
slides easily and indicates the correct pressure.
Effect of Altitude
Atmospheric pressure is like the thickness of frosting on a cake. Where
it is thickest it weighs more per square inch than where it is thin. At
sea level, where the atmosphere is the thickest, it is heavier than atop
a mountain.
As altitude increases, atmospheric pressure or its weight per square
inch decreases. Altitude affects the boiling point of water. Where
altitude is least, at sea level, water boils at 212° F. As altitude
increases the boiling point of water decreases.
The same is true in a pressure canner. Under 10 pounds pressure at sea
level, water boils at 240° F. As altitude increases, the temperature in
a pressure canner at 10 pounds of pressure is less than 240°. This
difference is enough to affect the safety of canned products at
altitudes above 2,000 feet.
[Illustration: Fred Farout
Processing times and pressures should be adjusted for altitude
change.]
Processing time for a particular vegetable is the time it takes to heat
the coldest part of the jar to a temperature of 240° F, and maintain it
long enough to kill any _C. botulinum_ spores present. At an altitude of
2,000 feet, it takes 11 pounds of gage pressure for water to boil at
240°. For each additional 2,000 feet increase in altitude, 1 pound of
pressure should be added.
For pressure canners that have the pressure control, the 15 pounds
pressure weight should be used at altitudes above 2,000 feet for canning
low-acid food.
At the end of processing, pressure inside the jars as well as inside the
canner is 10 pounds. The pressure inside the canner should be allowed to
drop slowly. If pressure inside the canner is released too rapidly,
pressure inside the jars will be great enough to force the contents,
especially liquid, out of the jars. This may prevent a jar from sealing
if a piece of food lodges on the top of the sealing rim. It may even
break the jar.
Remove the lid from the canner as soon as the pressure drops. Jars
should then be taken out and allowed to cool to room temperature
quickly. A type of non-toxic spoilage called flat sour can occur if the
jars are allowed to stand in the canner for long periods.
When using the steam-pressure canner, the pressure given is for
altitudes less than 2,000 feet above sea level. If you live in an area
with a higher altitude, it is necessary to make an adjustment in
pressure. See the next chapter for details.
Home Canning of Fruits and Vegetables
_by Carole Davis_[7]
Canning in the home is increasing in popularity as a method of food
preservation. Economic considerations are causing consumers to look for
ways to stretch their food dollars. By having their own gardens and
canning the harvested produce, they often can save money. Eating quality
of home-canned products encourages some individuals to can. The activity
of growing or obtaining produce and preserving it in the home sometimes
gives people a sense of personal achievement and satisfaction.
In canning, food is preserved by applying heat to prepared food in
containers so that micro-organisms that cause spoilage or food poisoning
are destroyed and enzymes that cause undesirable quality changes in the
flavor, color, and texture of food are inactivated. Preservation of food
by canning also depends on sealing the food in sterile, airtight
containers to prevent it from coming in contact with micro-organisms in
the environment.
Canning is not a difficult technique, but it must be done properly to
avoid spoilage and food poisoning, such as the often fatal botulism. It
is extremely important that only tested reliable instructions are used,
such as those found in U.S. Department of Agriculture publications.
Based on scientific research, specific instructions have been developed
for preparing, packing, and processing each food. Instructions should be
followed exactly from beginning to end—without taking any shortcuts or
altering any recipes.
Acidity of the food is the chief factor in influencing the time and
temperatures necessary for processing. The more acid the products, the
easier spoilage organisms are destroyed by heat. Acid foods—such as
tomatoes, fruits, and pickled vegetables—can be safely processed at the
temperature of boiling water in a boiling-water-bath canner. If spoilage
organisms are not killed by adequate processing, they will continue to
grow and could reduce the acid in the canned product, thus encouraging
the growth of more dangerous organisms, such as _Clostridium botulinum_.
Low-acid foods—all vegetables, except for tomatoes—require a more severe
heat treatment than acid foods to kill the organisms. The only safe way
to can these foods is with a steam-pressure canner, one with a weighted
or dial gage, to obtain temperatures above boiling. _Clostridium
botulinum_ is extremely dangerous in these low-acid foods because if it
is present, and the heat treatment has been insufficient, it can grow
and produce a deadly toxin in the sealed containers.
Processing times are based on sea level conditions where water boils at
212° F or, when under 10 pounds of pressure, at 240°. As the altitude
increases, the temperature at which water boils decreases. Therefore, at
altitudes above sea level you need to make adjustments in canning
instructions to insure that foods are adequately processed.
When using a boiling-water-bath canner you must add more time in
processing, as given in the table.
At altitudes above sea level it takes more than 10 pounds of pressure
for the temperature of boiling water to reach 240° F.
When using the steam-pressure canner, the pressure must be increased
although the time remains the same as that recommended for sea level. At
altitudes above 2,000 feet, process as follows:
Altitude Pounds of pressure
2,000 feet 11
4,000 feet 12
6,000 feet 13
8,000 feet 14
10,000 feet 15
Altitude Corrections for Boiling Water Bath
Increase processing time if the time
recommended is:
Altitude (feet) 20 minutes or less More than 20 minutes
1,000 1 minute 2 minutes
2,000 2 minutes 4 minutes
3,000 3 minutes 6 minutes
4,000 4 minutes 8 minutes
5,000 5 minutes 10 minutes
6,000 6 minutes 12 minutes
7,000 7 minutes 14 minutes
8,000 8 minutes 16 minutes
9,000 9 minutes 18 minutes
10,000 10 minutes 20 minutes
Equipment
Use jars made especially for home canning so the jars will be the right
size for the processing time and temperature used, properly heat
tempered, and resistant to mechanical shock. Always check jars before
using to be sure they do not have nicks or cracks. Wash jars in hot,
soapy water and rinse well.
It is important to use standard jar closures. They are designed to fit
home canning jars correctly, and are made from suitable materials to
provide a proper seal. One of the most popular types is the two-piece
lid with a metal ring or band and a flat metal disk with a sealing
compound. Flat metal disks can be used only once since they may not seal
properly if reused. Metal bands may be used repeatedly if they are not
rusted or dented.
[Illustration: Screw ring band and disk.]
Wash and rinse lids and bands. Metal lids with sealing compound may need
boiling or holding in boiling water for a few minutes; follow the
manufacturer’s directions. Porcelain-lined zinc caps with rubber
shoulder rings can also be used to seal jars. Rubber rings should be
used only once.
Water-bath canners are readily available on the market. However, any
large metal container may be used for a water-bath canner if it is deep
enough so the water is well over the tops of the jars and has space to
boil freely. Allow 2 to 4 inches above jar tops for brisk boiling. The
container or canner must have a tight fitting cover and a rack to allow
water to circulate under the jars.
The steam-pressure canner is made of heavy metal and has a cover which
fastens to make the pan steam-tight. The cover is fitted with a safety
valve, a petcock or vent, and a gage—either weighted or dial. All parts
of the canner must be clean and in good working order. Check the gage
before the canning season, and also during the season if canner is used
often. The weighted ones need only be checked to determine if they are
thoroughly clean. A dial gage can be tested for accuracy by a county
Extension agent or an equipment manufacturer.
A pressure saucepan may be used for canning pint jars of food. However,
20 minutes must be added to the processing time recommended for a
particular food canned with the pressure canner. This is because
pressure saucepans heat and cool more rapidly than pressure canners do.
Thus additional time is needed to compensate for the otherwise reduced
exposure of the food to heat.
Selecting and Preparing
Home-canned foods will be no better than the raw products with which you
begin. Fruits and vegetables should be of good quality with no bruises
or soft spots. Be sure to choose fresh, firm, ripe fruits and young
tender vegetables. Use them before they lose their freshness. Do not use
overripe produce because some foods lose acidity as they mature, and the
recommended processing time may not be adequate.
Wash all fruits and vegetables thoroughly, but gently, to remove dirt
which contains bacteria. Wash small quantities at a time under running
water or through several changes of water. Lift fruits and vegetables
out of the water so the dirt will not resettle on the food. Do not let
fruits or vegetables soak, as they may lose flavor and food value. Peel
and cut or slice produce as indicated in instructions for each specific
fruit or vegetable.
Fruits and vegetables may be packed raw into jars, or preheated and
packed hot. Raw or cold pack means that raw, unheated food is placed in
jars and covered with boiling hot sirup, juice, or water. When foods are
hot packed they are heated in sirup, water or steam, or juice for a
specified length of time and then packed hot into jars.
Most raw fruits and vegetables can be packed fairly tightly into
containers because they cook down during processing. However, raw corn,
lima beans, and peas should be packed loosely because they expand during
processing.
Hot food should be packed fairly loosely. It should be at or near the
boiling temperature when packed. There should be enough sirup, water, or
juice to fill in around the solid food in the container and to cover the
food. Food at the top of the container may darken if not covered with
liquid.
Do not overpack containers as this may result in underprocessing. It is
necessary to leave headspace between the lid and the top of the food or
liquid in the jar because there will be some expansion of food during
processing. The amount of headspace varies with the product, style of
pack, and method of heat sterilization, so follow directions for each
fruit or vegetable.
When using the flat metal lid with sealing compound, put the lid on a
clean jar rim, with sealing compound next to the glass. Then screw the
metal band down firmly. The lid will still have enough “give” to let
steam escape during processing. Do not tighten the band further after
removing the jar from the canner.
When using the porcelain-lined zinc cap, fit the wet rubber ring down on
the jar shoulder. Fill the jar and wipe clean the rubber ring and jar
rim. Screw the cap down firmly and turn back ¼ inch. When the jar is
removed from the canner, tighten the cap to complete the seal.
Processing Fruits
Sugar or sugar-water sirup is often added to fruits to help them hold
their shape, color, and flavor. Sugar can be added in the dry form to
very juicy fruits.
To make sugar sirup—mix sugar with water or juice extracted from the
fruit. Proportions for 3 types of sirup are as follows:
Type of Sirup Sugar (cups) Liquid (cups)
Thin 2 4
Medium 3 4
Heavy 4¾ 4
Heat sugar and water or juice together until sugar is dissolved.
Fruit may be canned without sweetening—in its own juice or in water—for
special diets. Processing time is the same for unsweetened fruit as for
sweetened because sugar is not needed to prevent spoilage.
Process fruits by the boiling-water-bath method. Work only with the
quantity of food needed for one canner load at one time.
As each jar is filled, adjust the lid, and place the jar on the rack in
the water-bath canner about one-half full of hot or boiling water for
raw or hot pack, respectively. Be sure the water is 1 to 2 inches over
the tops of the jars, and there is an additional 1- to 2-inch space to
allow the water to boil freely.
Cover the canner and when the water comes to a rolling boil, start to
count the processing time. Boil gently and steadily for the recommended
time for the fruit you are canning. A definite length of time is
recommended for processing each kind of fruit.
When the processing time is completed, immediately remove the jars from
the canner with a pair of jar tongs. Adjust the jar lids if necessary.
Cool the jars on a rack or folded towel away from drafts.
[Illustration: Hot packing peaches.]
[Illustration: Covering peaches with a boiling sirup solution.]
Processing Vegetables
A steam-pressure canner must be used for processing all vegetables
except tomatoes and pickled vegetables. Work only with the quantity of
vegetable needed for one canner load at a time. As each jar is filled,
adjust the lid, and place the jar in the pressure canner containing 2 to
3 inches of hot or boiling water for raw or hot pack, respectively, to
keep food hot.
The manufacturer’s directions for general operation of the canner you
are using should be followed. A few pointers on the use of any canner
follow:
—Use 2 to 3 inches of boiling water in the bottom of the canner.
—Set filled containers on rack in canner.
—Fasten canner cover securely.
—Allow steam to escape from open petcock or weighted gage opening for at
least 10 minutes to drive all air from canner. Then close petcock or put
on weighted gage.
—When pressure reaches 10 pounds (240° F), start counting processing
time. Keep pressure constant by regulating heat under the canner.
—When processing time is completed, remove the canner from heat
immediately. Cool undisturbed at room temperature until the pressure
registers zero. After a minute or two, slowly open the petcock or remove
the weighted gage. Unfasten the cover and tilt the far side up so steam
escapes away from you.
—Remove containers from canner with jar tongs.
—Adjust lids if necessary.
—Cool jars on a rack or folded towel away from drafts.
[Illustration: Cooling snap beans on a rack. Leave space between
jars so air can circulate.]
Day-After Check
Jars should be examined after they have cooled, but within 24 hours
after processing, to be sure a seal has been obtained. To test a jar
that has a flat metal lid, press the center of the lid; if the lid is
down and will not move, it is sealed. Turn jars with porcelain-lined
zinc caps partly over in your hands; if they do not leak, they are
sealed.
When jars are thoroughly cooled, metal screw bands should be carefully
removed. Wipe outside of jars clean, and label jars to show date and
contents. Store in cool dry place. If you find a jar that did not seal,
use food right away or re-can the food immediately; empty the jar, pack
and process the food as if it were fresh.
Look for Spoilage
Check dates on jar labels to be sure you first use food that has the
earliest processing date. Before opening any jar for use, look at it
carefully for spoilage signs. If it leaks, has a bulging lid, spurts
liquid when opened, or has an off-odor or mold, then do not use it. _Do
not even taste it._ Destroy it out of the reach of children and pets.
Canned vegetables may contain the toxin that causes botulism without
showing any visible signs of spoilage. Therefore, boil all home-canned
vegetables covered for at least 10 minutes before tasting or serving.
Heating generally makes any odor of spoilage more evident.
If the food appears to be spoiled, foams, or has an off-odor during
heating, destroy it.
How to Can Cut Green Beans[8]
1. Select green beans:
Choose young, tender beans
Allow 1½ to 2½ pounds of fresh beans for each quart to be canned
2. Prepare green beans:
Wash beans
Trim ends
Cut into 1-inch pieces
3. Pack into jars:
To pack raw—
Pack raw beans tightly into jar
Leave ½-inch space at top of jar
Add ½ teaspoon salt to pints; 1 teaspoon to quarts
Cover with boiling water to ½ inch from top of jar
Wipe jar rim clean
Adjust jar lid
Process in pressure canner at 10 pounds pressure (240° F)
Pints—20 minutes
Quarts—25 minutes
(At altitudes above sea level, increase pressure according to
instructions in early part of chapter)
To pack hot—
Cover cut beans with boiling water; boil 5 minutes
Pack hot beans loosely into jar to ½ inch of top
Leave ½-inch space at top of jar
Add ½ teaspoon salt to pints; 1 teaspoon to quarts
Cover with boiling water to ½ inch from top of jar
Wipe jar rim clean
Adjust jar lid
Process in pressure canner at 10 pounds pressure (240° F)
Pints—20 minutes
Quarts—25 minutes
(At altitudes above sea level, increase pressure according to
instructions given earlier)
4. Allow pressure to return to 0
5. Remove jars from canner
6. Complete seals, if necessary
How to Can Peaches[9]
1. Select peaches:
Choose fresh, firm, ripe fruit, with no soft spots or bruises
Allow 2 to 3 pounds of fresh peaches for each quart to be canned
2. Prepare peaches:
Wash peaches
Dip in boiling water; then in cold water
Slip off skins
Cut in halves and remove pits. Slice if desired
3. Prevent darkening:
Drop peeled peaches into solution of 2 tablespoons each of salt
and vinegar per gallon of water
Drain just before heating or packing raw
4. Pack into jars:
To pack raw—
Pack raw peaches in jar to ½ inch of top
Cover with boiling sirup (See sirup table)
Leave ½-inch space at top of jar
Wipe jar rim clean
Adjust jar lid
Process in boiling-water bath—
Pints—25 minutes
Quarts—30 minutes
(At altitudes above sea level, increase processing time according
to table near start of chapter)
To pack hot—
Heat peaches through in hot sirup (See sirup table). If fruit is
very juicy, heat it with sugar, adding no liquid
Pack hot fruit in jar to ½ inch of top
Cover with boiling sirup
Leave ½-inch space at top of jar
Wipe jar rim clean
Adjust jar lid
Process in boiling-water bath—
Pints—20 minutes
Quarts—25 minutes
(At altitudes above sea level, increase processing time according
to table near start of chapter)
5. Remove jars from canner
6. Complete seals, if necessary
Freezing Your Garden’s Harvest
_by Annetta Cook_[10]
The growing season brings an abundance of fruits and vegetables freshly
harvested from your garden. The unmatchable sweetness of peas cooked
fresh from the pods, the tender-crisp texture of fresh broccoli, the
delectable flavor of sweet juicy strawberries are irresistible. It is
always a disappointment when the growing season is over. You may have
more produce than you were able to use within a short time, so why not
savor its just-picked freshness during the autumn and winter
months—freeze it!
Of all the methods of home food preservation, freezing is one of the
simplest and least time-consuming. The natural colors, fresh flavors,
and nutritive value of most fruits and vegetables are maintained well by
freezing. However, to freeze foods successfully—that is, to preserve
their quality—produce must be carefully selected, prepared and packaged,
and properly frozen. Be sure to use reliable home-freezing directions
such as those found in U.S. Department of Agriculture publications.
Unless recommended practices and procedures are observed, the food’s
eating quality will be a disappointment.
The first consideration before deciding whether to freeze the garden’s
harvest is whether your freezer can maintain temperatures low enough to
preserve quality of the food during freezer storage. Storage
temperatures must be 0° F (-18° C) or below to help prevent unfavorable
changes in the food, including growth of bacteria. The temperature
control of your freezer should be adjusted so the warmest spot in the
freezer will always be at 0° F or lower. Freezers and most two-door
refrigerator-freezer combinations are best suited for long storage of
home-frozen fruits and vegetables since they can be set to maintain this
temperature.
Proper preparation of produce is also important to insure high eating
quality of frozen vegetables and fruits. Vegetables, except green
peppers and mature onions, maintain better quality during freezer
storage if blanched, or heated briefly, before freezing.
Blanching is necessary to prevent development of off-flavors,
discoloration, and toughness in frozen vegetables. Besides stopping or
slowing down the action of enzymes responsible for these undesirable
changes, blanching also softens the vegetable, making it easier to pack
into containers for freezing.
Fruit does not need to be blanched before freezing. However, most fruits
require packing in sugar or sirup to prevent undesirable flavor and
texture changes in the frozen product. Sugar, either alone or as part of
the sirup, plus the acidity of fruit retards enzyme activity in fruit
stored at 0° F or below.
Packaging Material
Material selected for packaging fruits and vegetables for freezing must
be moisture-vapor-proof or moisture-vapor-resistant to keep the food
from drying out and from absorbing odors from other foods in the
freezer. Loss of moisture from the food causes small white areas called
“freezer burn” to develop. These areas are not harmful, but if extensive
they can cause the food to become tough and lose flavor.
Suitable packaging materials include rigid plastic food containers,
plastic freezer bags, heavy aluminum foil, freezer paper or plastic
film, glass freezer jars, and waxed freezer cartons. Collapsible,
cardboard freezer boxes are frequently used as an outer covering for
plastic bags to protect them against tearing.
Select packaging materials suiting the shape, size, and consistency of
the food. Rigid containers are suited for freezing all foods, but are
especially good for fruit packed in liquid. Non-rigid containers are
best for fruits and vegetables packed without liquid. Paper, plastic, or
foil wraps are ideal for freezing bulky vegetables such as broccoli,
corn on the cob, and asparagus.
Rigid containers with straight sides and flat bottoms and tops stack
well in the freezer. They take up less freezer space than rounded
containers, containers with flared sides, and bulky, wrapped packages or
plastic bags without protective outer cartons. Containers with straight
sides or those that are flared, having wider tops than bottoms, are
preferred for easy removal of the food before thawing. If the opening is
narrower than the body of the container, the food will have to be
partially thawed so you can get it out of the container.
Freezer containers and bags are available in a variety of sizes. Do not
use those with more than ½-gallon capacity for freezing fruits and
vegetables since the food will freeze too slowly, causing poor quality
food.
Choose a container that will hold enough food for one meal for your
family. You may wish to put up a few smaller packages for use when some
family members are not home or to go with your family-size packages when
guests are present for meals.
Pack foods tightly into containers. Since most foods expand during
freezing, leave headspace between the packed food and closure.
For fruits that are in liquid, pureed, or crushed and packed in
containers with wide openings, leave ½-inch headspace for pints, 1-inch
headspace for quarts. If containers with narrow openings are used, leave
¾-inch headspace for pints, 1½-inch headspace for quarts.
For fruits and vegetables packed without liquid, leave ½-inch headspace
for all types of containers. Vegetables that pack loosely, such as
asparagus and broccoli, require no headspace.
Any container for freezer use must be capable of a tight seal. Rigid
containers should have an airtight-fitting lid.
Press out all air from the unfilled parts of plastic bags. Immediately
twist the top of each bag and securely tie it with a paper- or
plastic-covered wire twist strip, rubber band, or string to prevent
return of air to the bag.
Some bags may be heat-sealed with special equipment available on the
market. Follow the manufacturer’s directions.
Edges and ends of paper, foil, or plastic wraps should be folded over
several times so the wrap lies directly on top of the food and all air
has been pressed out of the package. Seal the ends with freezer tape to
hold them securely in place.
Selecting and Preparing
Grow varieties of fruits and vegetables that freeze well. Your county
Extension office can provide information on suitable varieties that grow
well in your locality.
Produce selected for freezing should be of optimum eating quality.
Freezing only preserves the quality of produce as it is at the time of
freezing. It never improves quality.
Fruits to be frozen should be firm and ripe. Underripe fruit may have a
bitter or off-flavor after freezing. Pick berries when ripe and freeze
them as soon after picking as you can. Some fruits—apples, peaches,
pears—may need to ripen further after harvesting. But take care they
don’t get too ripe. Frozen fruit prepared from overripe fruit will lack
flavor and have a mushy texture.
Choose young, tender vegetables for freezing. Since vegetables lose
quality quickly after harvest, freeze them as soon as possible for
maximum quality. The sugar in corn, peas, and lima beans is rapidly lost
when held too long before freezing. If you must hold vegetables and ripe
fruits for a short while, refrigeration will help retain the just-picked
freshness better than leaving produce at room temperature.
Wash small quantities of fruit gently in cold water. Do not permit fruit
to stand in water for any length of time since it will become
water-soaked and lose flavor and food value. Drain fruit thoroughly.
Peel fruit and remove pits or seeds. Halve, slice, chop, crush, or puree
fruit as indicated in the instructions for each specific fruit. Some
fruit, especially berries, may be left whole, but remove stems or hulls.
Work with small quantities of fruit at a time, particularly if it is
fruit that darkens rapidly. Two to three quarts is an adequate amount to
handle at one time.
Pack fruit by sirup pack, sugar pack, or unsweetened pack. Most fruit
has better texture and flavor with a sweetened pack. Apples, avocados,
berries, grapes, peaches, persimmons, and plums can all be frozen
satisfactorily without sweetening, but the quality is not quite as good
as freezing in sirup or sugar. An unsweetened pack will give as good a
quality product for gooseberries, currants, cranberries, rhubarb, and
figs as a sweetened pack.
_Sirup pack._ Make a sugar sirup by dissolving sugar in water. A 40%
sirup (3 cups of sugar to 4 cups of water) is recommended for freezing
most fruits. Sirups containing less sugar are sometimes used for
mild-flavored fruits; those with more sugar for very sour fruits. The
type of sirup to use is specified in the directions for freezing each
fruit. Allow ½ to ⅔ cup of sirup for each pint of fruit. Cut fruit
directly into the freezer container, leaving the recommended headspace.
Add sirup to cover fruit.
[Illustration: Slicing strawberries before freezing in a sugar
pack.]
_Sugar pack._ Cut fruit into a large bowl. Sprinkle with sugar. The
amount of sugar to use is specified in freezing directions for each
fruit. Mix gently until juice is drawn from the fruit and all the sugar
is dissolved. Pack fruit and juice into freezer containers.
_Unsweetened pack._ Some fruit may be packed dry, without added liquid
or sugar. Other fruit, particularly if it darkens rapidly, can be
covered with water to which ascorbic acid has been added. Crushed fruit
or sliced fruit that is very juicy can be packed in its own juice
without added liquid.
For all packs except the dry, unsweetened pack, liquid—either sirup,
juice, or water—should completely cover the fruit. This prevents the top
pieces from changing color or losing flavor due to exposure to air in
the headspace.
A small crumpled piece of waxed or parchment paper placed on top of the
fruit helps keep it pressed down in the liquid once the container has
been sealed. The paper should loosely fill the headspace area. Do not
use aluminum foil since acid in the fruit can cause the foil to pit
(form holes), and tiny pieces of foil may drop into the food.
_Anti-darkening._ Many fruits darken during freezing, particularly if
not kept under liquid. Darkening occurs when the fruit is exposed to
air. Since a small amount of air is in the liquid as well as the tissues
of fruit, some darkening can occur even when the fruit is submerged in
liquid. To help retard darkening during freezer storage, add ascorbic
acid (vitamin C) to the fruit during preparation.
Ascorbic acid is available in several forms from drug stores, some
freezer locker plants, and some grocery stores that sell freezing
supplies. Crystalline ascorbic acid is easier to dissolve in liquid than
powder or tablet forms. The amount of ascorbic acid to use is given in
the directions for those fruits where use of ascorbic acid is
beneficial. Ascorbic acid mixtures containing sugar, and sometimes
citric acid, also are available. Follow the manufacturer’s directions
for use of these products.
In preparing vegetables, wash a small quantity of the vegetable gently
in several changes of cold water. Lift the vegetable out of the water
each time so all dirt will settle to the bottom of the sink or pan.
Shell, husk, or peel and trim. Some vegetables such as lima beans, corn
on the cob, and asparagus require sorting for size, since blanching
times depend on size of the pieces.
Blanch the vegetable (this is not necessary for green peppers and mature
onions). Most vegetables are blanched by heating them in boiling water.
A blancher consisting of a tall kettle, basket, and cover is convenient
to use and can be purchased at most department or farm supply stores.
However, any large pan which can be fitted with a wire or perforated
metal basket and covered is suitable.
To insure adequate blanching, immerse a basket containing a small amount
of the vegetable (1 pound) into a large amount of boiling water (at
least 1 gallon). Start timing once the vegetable has been immersed and
the kettle is covered. Blanching time will vary with the vegetable and
the size of the pieces, so follow the recommended blanching times for
each vegetable.
Cool the vegetable by immersion in a large quantity of cold or iced
water. Rapid cooling is necessary to stop the food from cooking. Cool
the vegetable for about the same length of time as it was heated. Once
cooled, do not leave the vegetable standing in water, as loss of flavor
and food value can occur. Drain the cooled vegetable thoroughly before
packaging.
Other methods of blanching and cooling are recommended for some
vegetables. For example, mushrooms are heated by sauteing, tomatoes by
simmering in their own juice. These foods are cooled by setting the pan
of food in cold or iced water to speed cooling.
Freezing and Storing
After packing and sealing containers, label them with the name of the
food, type of pack (for fruits), and date of freezing. Freeze food soon
after packing, placing a few packages at a time in the freezer as you
have them ready.
Freeze food at 0°F or below. Do not load the freezer with more food than
can be frozen in 24 hours. Usually 2 to 3 pounds of food per cubic foot
of freezer capacity can be frozen at a time. Place packages on freezing
coils or plates or in fast-freeze section of freezer, leaving a space
between each package. Loading the freezer in this manner enables the
food to be frozen quickly. Freezing foods too slowly can result in loss
of quality.
Once food has frozen, stack containers. Keep freezer surfaces relatively
free from frost to insure maximum operating efficiency of your freezer.
Fruits and vegetables stored at 0° F or below will maintain high quality
for 8 to 12 months. Unsweetened fruit loses quality more rapidly than
sweetened fruit.
Keeping food longer than the recommended time will not make it unsafe to
eat, but some quality loss can occur.
Thawing
Home-frozen fruits and vegetables are convenient and easy to use since
most of their preparation is done before freezing. Thaw frozen fruit in
the refrigerator, or at room temperature in a pan of cool water. Leave
fruit in the unopened freezer container.
A pint package of fruit frozen in sirup will take about 6 to 8 hours to
thaw in the refrigerator, or ½ to 1 hour in a pan of cool water. Fruit
in sugar packs takes less time. Unsweetened packs need more time than
sirup packs. For best eating quality, serve fruit with a few ice
crystals remaining.
Cook most frozen vegetables without thawing first. (Corn on the cob and
leafy vegetables require partial thawing to insure even cooking.) Add
the vegetable to boiling salted water. Use 1 cup of water and 1 teaspoon
of salt for each quart of vegetable with these exceptions: Use 2 cups of
water for lima beans; water-to-cover for corn on the cob. Cover the
saucepan during cooking. Cook the vegetable only until tender. Avoid
overcooking.
Consult timetable in freezing directions for recommended times for
cooking home-frozen vegetables.
How to Freeze Strawberries[11]
1. Select strawberries:
Choose firm, ripe red berries with a slightly tart flavor
Allow about 1½ quarts fresh strawberries for each quart to be
frozen
2. Prepare strawberries:
Wash berries in cold water; drain well
Remove hulls
3. Pack into rigid freezer containers:
To pack in sirup—
Prepare ahead of time a 50 percent sirup by dissolving 4¾ cups
sugar in 4 cups of water; this will make 6½ cups sirup
Add about ½ cup sirup to each container
Put berries into prepared containers
To pack in sugar—
Add ¾ cup sugar to each quart berries
Mix gently until sugar is dissolved and juice is drawn from
berries
Pack strawberries with juice in containers
To pack unsweetened—
Put berries into containers
For better color, cover with cold water containing 1 teaspoon
ascorbic acid per quart of water
For all packs—
Press fruit gently down in each container; add liquid (sirup,
juice, or water) to cover fruit, unless fruit is packed dry,
unsweetened
Leave recommended amount of headspace (See earlier reference)
Put a small piece of crumpled waxed paper on top of berries to
keep them down in liquid
Wipe all liquid from top and sides of containers
Seal tightly with lid
Label with name of fruit, type of pack, and date of freezing
4. Freeze strawberries:
Immediately after packaging, place berries in freezer set at 0° F
or below; leave space around each container for faster
freezing
Do not freeze more than 1 quart of berries per cubic foot of
freezer capacity at a time
Stack containers of berries once frozen; store at 0° or below
How to Freeze Green Peas[12]
1. Select green peas:
Choose bright-green, plump, firm pods with sweet, tender peas (do
not use immature or tough peas)
Allow 4 to 5 pounds fresh peas for each quart to be frozen
2. Prepare green peas:
Shell peas
Wash shelled peas in cold water; drain
3. Blanch green peas:
Bring 1 gallon water to a boil in a large kettle
Put peas (1 pound) in blanching basket
Lower basket into boiling water
Cover kettle and heat peas 1½ minutes
Chill peas promptly in cold or iced water 1½ minutes
Drain cooled peas
4. Pack green peas:
Pack drained, blanched peas in freezer containers (See reference
on containers in early part of chapter)
Leave ½-inch headspace between peas and closure
Seal containers tightly
Label each package with name of vegetable and date
5. Freeze green peas:
Immediately after packaging, place peas in freezer set at 0° F or
below; leave space around each container for faster freezing
Do not freeze more than 2 to 3 quarts of peas per cubic foot of
freezer capacity at a time
Stack packages of peas once frozen; store at 0° F or below
For Further Reading:
_Home Freezing of Fruits and Vegetables_, U.S. Department of Agriculture
H&G Bul. No. 10, on sale by Superintendent of Documents, U.S.
Government Printing Office, Washington, D.C. 20402. 75¢.
Jellies, Jams, Marmalades, Preserves
_by Catharine C. Sigman and Kirby Hayes_[13]
Changing fruit into a variety of products such as jellies, jams,
marmalades, and preserves can be most rewarding. These products serve as
a good way to use fruit that is not completely suitable for canning or
freezing, while adding variety and economy to the home food preservation
plan.
Jams, jellies, and preserves are similar in that they are preserved
using sugar, and all are jellied or partially jellied. Each differs from
the other due to the fruit used, ratio of ingredients, and methods of
preparation.
Jelly is made using fruit juice. It is clear and firm enough to hold its
shape when removed from the jar.
Jam is made from crushed or macerated fruit. Less firm than jelly, it
spreads more easily.
Conserves are jams made from a mixture of fruits including citrus.
Sometimes nuts and raisins are added.
Preserves are whole fruits or large pieces of fruit in a sirup that
varies in thickness.
Marmalades are usually made from pulpy fruits, with skin and pulp
suspended in a clear, jellied liquid. For citrus marmalades, the peel is
sliced very thin.
Butters are made by cooking fruit pulp with sugar to a thick consistency
which spreads easily.
Jellied fruit products need a balanced ratio of fruit, acid, pectin, and
sugar for best results.
Fruit provides the characteristic color and flavor, and furnishes at
least part of the pectin and acid that combines with added sugar to give
the desired gel. Full flavored fruits are needed to offset the dilution
of flavor by the large proportion of sugar used.
Pectin is the actual jellifying substance and is found in many fruits in
adequate quantity. If pectin is lacking, apple juice extract or
commercial pectin may be used. All fruits have more pectin when
underripe.
Commercial pectin is available in both liquid and powder forms. It is
essential to follow the manufacturer’s instructions or tested recipes as
in U.S. Department of Agriculture publications. These preparations
generally bring higher yields plus the advantages of being able to use
fully ripe fruit, with a shorter cook time and more uniform results.
Acid content varies among fruits and is higher in underripe fruits. Acid
is needed both for gel formation and for flavor. When fruits are low in
acid, lemon juice or citric acid may be used. Commercial pectins also
have added acid.
Either beet or cane sugar in fruit products acts as a preserving agent,
helps in forming the gel, and enhances the finished product’s flavor. In
preserves, sugar aids in firming the fruit or fruit pieces.
Sweeteners such as brown sugar, sorghum and molasses are not recommended
since their flavor overpowers the fruit flavor and their sweetness
varies.
Other than artificial sweeteners, suitable sugar replacements are light
corn sirup and light, mild honey. Neither can substitute fully for sugar
on a one-to-one basis. For best results use a tested recipe, but if one
is not available replace about ¼ to ½ of the sugar with corn sirup or
honey. Longer boiling (for recipes without pectin) may be required since
additional moisture is being added.
Fruits for jellied products without added pectin must be hard ripe and
full flavored, or in a proportion of ¾ fully ripe and ¼ underripe, in
order to provide the needed pectin. If liquid or powdered pectin is
used, fully ripe fruit is best.
After sorting to remove overripe or undesirable fruit, wash in cold
running water or several changes of cold water. Prepare fruit according
to the specific recipe, discarding any spoiled or bruised portions. Only
the amount needed should be prepared to prevent quality loss.
Jam and Jelly Equipment
Water bath canner
Jelly thermometer
Timer
Widemouth funnel
Large, flat-bottomed kettle (8-10 qt.)
Measures
Measuring cup and spoons
Food chopper or masher
Long-handled spoon
Colander
Ladle
Jar lifter
Jelly bag and cheesecloth
Jelmeter
Canning jars and fittings
Extraction
In jelly making, juice is extracted either by crushing, by limited
heating using small amounts of water, or by longer cooking with measured
amounts of water. Heating aids in pectin extraction for those recipes
not using added pectin.
The prepared fruit is put in a damp jelly bag or several thicknesses of
damp cheesecloth, tied, and hung to drip. The clearest juice will be
free run, but yields increase if the bag is pressed or twisted.
Re-straining this juice is recommended. Do not squeeze or press.
Jams, jellies, and preserves can be made with added pectin or without
it, depending on the fruit. Fruits such as raspberries, strawberries,
and peaches generally need added pectin. Apples, crabapples, currants,
plums, grapes, and quinces—if not overripe—contain enough pectin and
acid for good gel strength.
Pectin content can be checked visually by mixing 1 tablespoon of cool
cooked fruit juice and 1 tablespoon of denatured alcohol and mixing.
Fruit high in pectin will form a jellylike mass while fruit low in
pectin will show little clumping. Caution: Do not taste; the mixture is
poisonous.
Pectin may also be tested using a jelmeter. This graduated glass tube
measures the rate of fruit juice flow through the tube, giving a rough
estimate of the amount of pectin present.
Jellied fruit products made without added pectin require less sugar per
fruit unit and need longer boiling to reach the end point. The yield of
finished product is less than that with added pectin.
Pectin added to fruit, either in powder or liquid form, must be used in
recipes designating the type. Powdered pectin is mixed with the unheated
fruit juice or unheated crushed fruit.
Liquid pectin is added to the boiling fruit juice or fruit and sugar
mixture. The boiling time of 1 minute for both types is used and must be
accurately timed. Regardless of type, or whether pectin is used, you
must follow directions closely, taking accurate measurements.
When It’s Done
One of the largest concerns when making jelly without added pectin is to
know when it is done, or judging the end point. Two of the most
frequently used methods for testing doneness of jelly without added
pectin are the temperature test and the spoon or sheet test.
The temperature test is the most scientific method and probably the most
dependable. Before cooking jelly, take the temperature of boiling water
with a jelly or candy thermometer. Cook the jelly mixture to a
temperature 8° F higher than the boiling point of water. If cooked to
this point, the jelly mixture should form a satisfactory gel. Cook other
jellied mixtures to a temperature 9° higher than the boiling point of
water.
To get an accurate reading, place the thermometer in a vertical position
with the bulb completely covered by the jelly mixture but not touching
the bottom of the kettle. Stir jam, preserve, conserve, and marmalade
mixtures before taking the temperature. Read the thermometer at eye
level.
To test the jellying point by the spoon or sheet test, dip a cool metal
spoon into the boiling jelly mixture and lift the spoon so the sirup
runs off the side. When the sirup no longer runs off the spoon in a
steady stream, but two drops form together and sheet off the spoon, the
jelly should be done.
[Illustration: Pouring hot jelly mixture into canning jars.]
Once the jellying point is reached, quickly pour jelly into sterilized
containers. When sealing jelly with lids, use only standard canning jars
and new lids. Pour the boiling hot jelly mixture into sterilized hot
jars, leaving ⅛ inch head space. Wipe the jar rims clean, place hot
metal lids on jars with the sealing compound next to the glass, screw
the metal bands down firmly, and stand the jars upright to cool.
The paraffin seal is recommended only for jelly. Pour the boiling hot
jelly mixture into sterilized hot containers, leaving ½ inch head space.
Cover hot jelly with hot paraffin to make a single thin layer ⅛ inch
thick. Paraffin should touch all sides of the container. Prick air
bubbles in the paraffin.
Heat processing of jams, preserves, conserves, and marmalades is
recommended, especially in warm or humid climates. Place filled jars on
a rack in a water bath canner or other large container filled with hot
water. The water should be an inch or two over the tops of the jars.
Cover canner. Bring the water to a rolling boil and boil gently for five
minutes.
Remove the products from the canner immediately when the processing time
is up. Place the containers on a rack or folded cloth away from drafts
to cool.
Let jellied products stand overnight to avoid breaking the gel. Remove
screw bands, and label the containers with the name of the product and
the date. Store in a cool, dry place. Jellied products have a much
better flavor and color if stored only for a short time.
If It Doesn’t Gel
What if the jelly doesn’t gel? Try using it as a topping for pancakes or
ice cream, or try recooking the mixture. To remake jelly without added
pectin, heat the jelly to boiling and boil for a few minutes until the
jellying point is reached. Remove the jelly from the heat, skim, pour
into hot, sterilized containers and seal.
How to Prevent Problems With Jellied Products
Problem Cause Prevention
Formation of Excess sugar Test fruit juice with jelmeter for
crystals proper proportions of sugar
Undissolved sugar Wipe side of pan free of crystals
sticking to sides with damp cloth before filling
of kettle jars
Tartrate crystals Make grape jelly stock, and let
in grape juice tartrate crystals settle out
before making jelly. Then strain
through two thicknesses of
cheesecloth to remove crystals
Mixture cooked too Cook at a rapid boil. Remove from
slowly or too long heat immediately when jellying
point is reached
Syneresis or Excess acid in Maintain proper acidity of juice
“weeping” juice makes
pectin unstable
Storage place too Store in a cool, dark and dry place
warm or storage
temperature
fluctuated
Paraffin seal too Seal jelly with a single thin layer
thick of paraffin ⅛ inch thick. Prick
air bubbles in paraffin
Too soft Overcooking fruit Avoid overcooking as this lowers
to extract juice the jellying capacity of pectin
Incorrect Follow recommended instructions
proportions of
sugar and juice
Undercooking Cook rapidly to jellying point
causing
insufficient
concentration
Insufficient acid Avoid using fruit that is overripe.
Lemon juice is sometimes added if
fruit is acid deficient
Making too large a Use only 4 to 6 cups of juice in
batch at one time each batch of jelly
Too stiff or Overcooking Cook jelly mixture to a temperature
tough 8° F higher than the boiling
point of water or until it
“sheets” from a spoon
Too much pectin in Use ripe fruit
fruit
Cloudy Green fruit (starch) Use firm, ripe fruits or slightly
underripe
Imperfect straining Do not squeeze juice but let it
drip through jelly bag
Jelly allowed to Pour into jars immediately upon
stand before it reaching jellying point. Work
was poured into quickly
jars or poured
too slowly
Bubbles Kettle was not held Hold kettle close to top of jar and
close to top of pour jelly quickly into jar
jar as jelly was
poured, or jelly
was poured slowly
and air became
trapped in hot
jelly
May denote spoilage. Follow recommended methods to get
airtight seal
If bubbles are
moving, do not use
Mold Imperfect seal Use recommended methods to get
(denotes airtight seal
spoilage;
do not use)
Lack of proper Sterilize jelly glasses and all
sanitation equipment used
To remake with powdered pectin, measure ¼ cup sugar, ¼ cup water, and 4
teaspoons powdered pectin for each quart of jelly. Mix the pectin and
water and bring to a boil, stirring constantly. Add the jelly and the
sugar, stir thoroughly, and bring to a full rolling boil over high heat,
stirring constantly. Boil the mixture hard for 30 seconds, remove from
the heat, pour into hot containers and seal.
To remake with liquid pectin, measure ¾ cup sugar, 2 tablespoons lemon
juice, and 2 tablespoons liquid pectin for each quart of jelly. Bring
the jelly to a boil over high heat. Add the sugar, lemon juice and
liquid pectin and bring to a rolling boil, stirring constantly. Boil the
mixture hard for 1 minute. Remove the jelly from the heat, skim, pour
into hot, sterilized containers and seal.
High quality jellied products depend on many factors so there may be
several possible solutions to problems in making these products. Some
common problems and their prevention are given in the table.
For Further Reading:
_How To Make Jellies, Jams and Preserve at Home_, H&G Bul No. 56, on
sale by Superintendent of Documents, U.S. Government Printing
Office, Washington, D.C. 20402. 55¢.
Pickles, Relishes Add Zip and Zest
_by Isabelle Downey_[14]
Pickles or relishes can add zip and zest to your meals, snacks and party
refreshments. They contain small amounts of nutrients, depending on
ingredients used in making them. But they have little or no fat and are
low in calories, except for the sweet varieties.
Sun-drying, salting, smoking and pickling were methods used in ancient
times for preserving food. Pickling is still popular today.
Pickling is preserving foods in vinegar or brine or a combination of the
two. Other ingredients are sometimes added to make pickles crisp and
spicy.
Relishes and some pickles can be made in a few hours. Other pickles may
take three to six weeks.
There are four basic classifications of pickle products, depending on
ingredients used and method of preparation.
_Brined pickles_ are sometimes called fermented pickles and take three
weeks or longer to cure. Dilled cucumbers, sauerkraut and some
vegetables are often prepared this way. Cucumbers change from a bright
green to an olive or yellow green while the interior becomes uniformly
translucent. Sauerkraut is tart and tangy in flavor, creamy-white in
color, and crisp and firm.
_Fresh pack pickles_ are also called the quick process. This method is
very popular for the family with limited time. Ingredients are combined
and put directly in the jar to be heat processed, or combined and heated
a short time before being placed in the jar for heat processing.
_Fruit pickles_ are usually made of whole fruits simmered in a spicy,
sweet-sour sirup. Some of the favorites are peach, pear and watermelon
rind.
_Relishes_ are made from chopped fruits or vegetables (or a
combination), with seasonings added and cooked to a desired consistency.
They can be hot, spicy, sweet or sour, depending on the recipe used.
Corn relish, chili sauce, catsup, chow-chow and chutney are popular
examples.
Always use a tested recipe; one that is current and reliable. Too little
of one ingredient and too much of another could cause the pickles to be
unsafe to eat. Read the complete recipe before starting the preparation,
and be sure you understand exactly what you are to do. Check to see you
have all the ingredients. Accurate measurements and weights are most
important in making pickles and relishes if a quality and safe product
is to be the result.
Use only good quality fruits and vegetables. Select tender vegetables
and firm ripe fruit. Pears and peaches may be slightly underripe for
pickling. The pickling type cucumber is the variety you will want to
use. The salad (slicing) variety does not make a crisp pickle. Contact
your county Extension office for the variety grown in your area.
Wax-coated cucumbers bought from the vegetable counter are not suitable
for pickling because brine cannot penetrate the wax. Besides, cucumbers
for pickling should be used within 24 hours after gathering. If they are
kept—even refrigerated—longer than 24 hours before the pickling process
begins, you may have a poor quality product.
Always remove the blossom. This may contain fungi or yeasts which could
cause enzymatic softening of the cucumber. If whole cucumbers are to be
brined, you may want to leave a ¼-inch stem.
Do not use vegetables or fruits that have even a slight evidence of mold
or decay.
In preparing fruits and vegetables to be pickled, wash them thoroughly
in cold water whether they are to be peeled or not. Lift out of the
water each time, so soil that has been washed off will not drain back
over them. Rinse the pan thoroughly between each washing. This is a good
time to check again to see if you have fruits or vegetables that should
not be used. Too, you can sort as to size, shape and color. This makes
for a uniform pack and attractive product.
Ingredients
SALT—Pure granulated salt with no noncaking material or iodine added is
best. This is sold as pickling salt, “barrel” salt, and “kosher” salt.
Pickling salt is sold at the grocery store and “barrel” salt from many
farm supply stores.
Table salt contains noncaking materials that may interfere with
fermentation during brining. It also may make the brine cloudy. Iodized
salt may darken pickles. Never use ice cream salt or rock salt—they are
not food-pure.
VINEGAR—Use a 4 to 6 percent acidity (40 to 60 grain) cider or white
vinegar. Read the label, for if it does not have the amount of acidity
listed, it should not be used for making pickles or relishes. Some
vinegar has 19 percent acidity—this must be diluted. Directions are on
the label. Don’t use homemade vinegar since the acidity is not known.
Cider vinegar, used in most recipes, has a good flavor and aroma but may
discolor pears, cauliflower, onions; therefore white distilled vinegar
is used for these. If a less sour product is preferred, choose a recipe
that has more sugar. Do not use less vinegar than the recipe specifies.
SUGAR—Granulated, white sugar is used in most pickles. However, some
recipes have brown sugar as an ingredient and say so.
SPICES AND HERBS—Always use fresh spices and herbs for best flavor. They
deteriorate and lose their pungency in heat and humidity. If they are
not to be used immediately, store them in an airtight container in a
dark, dry, cool place.
Whole spices, if left in the jar with the pickles, will darken them;
therefore they can be tied in a thin cloth bag and removed just before
pickles are packed into the jar. Ground spices tend to darken pickles
and relishes.
WATER—It is best not to use hard water in brining. If you have hard
water, boil it in a stainless steel or uncracked enamel container for 15
minutes. Remove from heat, cover, and let sit for 24 hours. Remove any
scum which might have formed. Slowly pour water from the container so
that sediment will not be disturbed. The water is now ready to use.
Equipment
Having the right kind, size and amount of equipment and tools can save
you time and energy. Check these the day before you plan to make your
pickles. Otherwise you may not have what you need.
For fermenting or brining use a crock or stone jar that has never had
fat or milk in it. An unchipped enamel-lined pan, glass or stainless
steel are also O.K. Do not use plastic.
To cover vegetables while they are in a brine, you will need a heavy
plate or large glass lid that fits inside the container. Use a filled
jar of water to hold the cover down, so that vegetables are kept below
the surface of the brine. Be sure the jar has a tight fitting lid.
For heating pickling liquids, use utensils of unchipped enamelware,
stainless steel, aluminum or glass. Do not use copper, brass, galvanized
or iron utensils; these metals may react with acids or salts and cause
undesirable color changes in pickles or form undesirable compounds.
Among small utensils that will help you do the job are measuring spoons,
stainless steel spoons, measuring cups, household scales, sharp knives,
vegetable peelers, large trays, canning tongs, ladle with a lip for
pouring, slotted metal spoons, footed colander or wire basket, canning
funnel, food chopper or grinder, and non-porous cutting board.
All pickles and relishes should be processed in a boiling-water bath
canner. Any large metal or enamel container may be used if it:
—Is deep enough to allow 2 inches or more of water above the tops of the
jars, plus extra space for boiling
—Has a close-fitting cover
—Is equipped with a wire or wooden rack
A steam-pressure canner can be used if it is deep enough. For this
purpose, set the cover in place without fastening it. Be sure the
petcock is wide open so that steam escapes and pressure is not built up.
Standard home canning jars are used for pickles and relishes. Do not use
jars and lids from commercially canned foods. They are designed for use
on special packing machines and are not suitable for home canning.
Select jars free from nicks, chips or any defects. As you wash the jars
in warm soapy water and rinse them, run your finger around the jar
opening to see if there is a defect. If there is, the jar will not seal.
Look at each new metal lid to be sure the sealing compound is even and
smooth. Check the metal screw band to see that it is not bent or rusty.
Bands can be used over and over again. As for pretreatment of lids and
bands, follow the manufacturer’s directions. Read these even if you have
used that brand before; the directions may have changed.
When using rubber rings get clean, new ones that are the right size for
the jars. Do not test these by stretching. Follow the manufacturer’s
directions as to pretreatment needed.
It is always best to follow current, reliable procedures as in U.S.
Department of Agriculture or Extension publications. This insures a
quality product and one that is safe to eat. Time, energy and money may
be wasted if you use outdated or careless canning procedures.
Fill the jars firmly and uniformly with the pickle product. Avoid
over-packing so tightly that the brine or sirup is prevented from
filling around and over the product. Slide a plastic spatula down each
side of the jar to remove any air spaces. Add enough liquid to cover the
pickles. Be sure to allow head space at the top of the jar as
recommended in the recipe. This means there is no food or liquid in that
space.
Wipe the rim, inside and top, and threads of the jar with a clean, damp
cloth to remove any particles of food, spices, seeds or liquid. A small
particle may prevent an airtight seal.
The two-piece metal cap (flat metal lid with sealing compound and metal
screw band) is the most commonly used closure. Read the manufacturer’s
directions on treatment needed to close the lid. These vary from one
manufacturer to another.
When using a porcelain-lined zinc cap with shoulder rubber ring, screw
the cap down firmly against the wet rubber ring, then turn it back
one-fourth inch. Immediately after processing and removal of the jar
from the canner, screw the cap down tight to complete the seal.
If liquid has boiled out of a jar during processing, do not open it to
add more liquid, because spoilage organisms may enter. This applies to
2-piece lids also. Seal the jar as it is.
Heat Treatment
All pickle products require heat treatment to destroy organisms that
cause spoilage and to inactivate enzymes that may affect flavor, color
and texture. Adequate heating is best achieved by processing the filled
jars in a boiling-water bath.
Spoilage organisms are in the air and there is danger of them
contaminating the food as it is transferred from boiler to jar. This can
happen when even the utmost care is taken. Therefore, boiling-water bath
processing is needed.
After adjusting the lid, put the jar on the rack into the actively
boiling water.
Now that the jar is in the water bath canner, fill the next jar.
Continue until all jars are in the canner. Be sure to leave a small
space around each jar. This allows the water to circulate. Water should
come 2 or more inches above jar tops; add boiling water if necessary.
Cover the canner with a close-fitting lid and bring the water back to
boiling as quickly as possible. Start to count the processing time when
the water returns to boiling, and continue to boil gently and steadily
for the recommended time according to the recipe.
When time is up, slide the canner from the hot range unit. Close windows
and doors so that a draft will not be blowing on jars as they are
removed. As you remove the lid, be sure to do this away from you so that
you will not be burned by steam. Remove one jar at a time, using your
canning tongs. Complete the seals if the manufacturer so directs. Set
jars upright, away from a draft, and several inches apart, on a dry
cloth or wire rack to cool. Do not cover with a cloth.
For fermented (brined) cucumbers and fresh-pack dills, start to count
the processing time as soon as all the filled jars are in the actively
boiling water. This prevents development of a cooked flavor and loss of
crispness.
Most pickle and relish recipe processing times are given for altitudes
less than 1,000 feet above sea level. If you are 1,000 feet or above,
you need to increase the recommended processing time. See table in
canning chapter by Carole Davis.
After 12 to 24 hours, check to make sure the jars have an airtight seal.
Read the manufacturer’s directions but if these are not given, here are
some general ways to tell if the seal is airtight. For the metal lid
with a sealing compound and the metal screw band, if the center of the
lid has a slight dip or stays down when pressed, the jar is sealed.
Another test is to tap the center of the lid with a spoon. A clear,
ringing sound means a good seal. A dull note, however, does not always
mean a poor seal. Another way to check for an airtight seal is by
turning the jar partly over. If there is no leakage, the jar may be
stored.
If the porcelain-lined zinc cap with rubber ring has been used, check
for airtight seal by turning the jar partly over. If there is no
leakage, the seal is tight.
If the jar is not sealed, use the product right away or recan it. To
recan, empty the jar, repack in another clean jar, use a new lid, and
reprocess the product as before.
If metal bands are used, these can be removed from jars after 24 hours
if you want to.
Wipe jars with a clean, damp cloth. Make a label for the jar. Put the
name of the product and date on the label.
Store canned pickles and relishes in a dark, dry, cool place where there
is no danger of freezing. Freezing may crack the jars or break the
seals, and let in bacteria.
Before using, always examine each jar for signs of spoilage. A bulging
lid or leakage may mean that the contents are spoiled.
When a jar is opened look for other signs of spoilage such as:
—Spurting liquid
—Mold
—Disagreeable odor
—Change in color
—Unusual softness, mushiness or slipperiness
_If there is ever the slightest indication of spoilage, do not eat or
even taste the contents._ Dispose of the contents so they cannot be
eaten by humans or animals. Also dispose of the lid.
After emptying the jar of spoiled food, wash the jar in hot, soapy water
and rinse. Boil in clean water for 15 minutes.
Pickle Problems
_Why are pickles soft or slippery?_
This generally results from microbial action which causes spoilage. Once
a pickle becomes soft it cannot be made firm again. Microbial activity
may be caused by
—Too little salt or acid
—Cucumbers not covered with brine during fermentation
—Scum not removed from brine during fermentation
—Insufficient heat treatment
—Seal is not airtight
—Moldy garlic or spices
Blossoms, if not removed from the cucumbers before fermentation, may
contain fungi or yeasts responsible for enzymatic softening.
_Why are pickles shriveled?_
—Using too strong a vinegar, sugar or salt solution at the start of
the pickling process. In making the very sweet or very
sour pickles, it is best to start with a dilute solution
and increase gradually to the desired strength
—Overcooking
—Overprocessing
_Why are pickles dark?_
—Use of ground spices
—Too much spice
—Whole spices left in jar
—Iodized salt
—Minerals in water, especially iron
—Overcooking
_What causes garlic to turn purple or blue?_
—Garlic contains anthocyanins, a water soluble pigment also found in
beets. This changes color very easily and with the acid
condition in pickles, turns blue or purple in color
_How can you tell if sauerkraut is spoiled?_
—Undesirable color
—Off odors
—Soft texture
_Why does kraut get soft?_
—Insufficient salt
—Too high temperatures during fermentation
—Uneven distribution of salt
—Air pockets caused by improper packing
_Why does kraut get pink?_
This is caused by growth of certain types of yeast on the surface of the
kraut due to:
—Too much salt
—Uneven distribution of salt
—Kraut improperly covered or weighted during fermentation
_Why does kraut turn dark?_
—Unwashed and improperly trimmed cabbage
—Insufficient juice to cover fermenting cabbage
—Uneven distribution of salt
—Exposure to air
—Long storage period
—High temperature during fermentation, processing and storage
For Further Reading:
_Making Pickles and Relishes at Home_, H&G Leaflet #92, on sale by
Superintendent of Documents, U.S. Government Printing Office,
Washington, D.C. 20402. 45¢.
Wine Making (with a note on vinegar)
_by Philip Wagner and J. R. McGrew_[15]
Grapes are the world’s leading fruit crop and the eighth most important
food crop in the world, exceeded only by the principal cereals and
starchy tubers. Though substantial quantities are used for fresh fruit,
raisins, juice and preserves, most of the world’s annual production of
about 60 million metric tons is used for dry (non-sweet) wine.
Wine is of great antiquity, as every Bible reader knows, and a
traditional and important element in the daily fare of millions. Used in
moderation, it is wholesome and nourishing, and gives zest to the
simplest diet. It is a source of a broad range of essential minerals,
some vitamins, and easily assimilated calories provided by its moderate
alcoholic content.
In its beginnings, winemaking was as much a domestic art as breadmaking
and cheesemaking. It still is, wherever grapes are grown in substantial
quantity. Though much wine is now produced industrially, many of the
world’s most famous wines are still made on what amounts to a family
scale, the grapegrower being the winemaker as well.
Production of good dry table wine for family use is not difficult,
provided certain essential rules are observed.
_The right grapes._ Quality of a wine depends first of all on the grapes
it is made from. As is true of other fruits, there are hundreds of grape
varieties. They fall in three main groups.
First, there are the classic _vinifera_ wine grapes of Europe. These
also dominate the vineyards of California, with its essentially
Mediterranean climate. But several centuries of trial have shown that
they are not at home in most other parts of the United States.
Second, there are the traditional American sorts such as Concord,
Catawba, Delaware, and Niagara, which are descendants of our wild grapes
and much grown where the _vinifera_ fail. They have pronounced aromas
and flavors, often called foxy, which, though relished in the fresh
state by many, reduce their value for wine.
Third, there are the French or French-American hybrids, introduced in
recent years and now superseding the traditional American sorts for
winemaking. The object in breeding these was to combine fruit resembling
the European wine grapes with vines having the winter hardiness and
disease resistance of the American parent. They may be grown for
winemaking where the pure European wine grapes will not succeed.
_What wine is._ Simply described, wine is the product of the
fermentation of sound, ripe grapes. If a quantity of grapes is crushed
into an open half-barrel or other suitable vessel, and covered, the
phenomenon of fermentation will be noticeable within a day or two,
depending on the ambient temperature. It is initiated by the yeasts
naturally present on the grapes, which begin to multiply prodigiously
once the grapes are crushed.
Fermentation continues for three to ten days, throwing off gas and a
vinous odor. In the process, the sugar of the grapes is reduced to
approximately half alcohol and half carbon dioxide gas, which escapes.
Fermentation subsides when all the sugar has been used up. The murky
liquid is then drained and pressed from the solid matter and allowed to
settle and clear in a closed container.
The resulting liquid is wine—not very good wine if the constituents of
the grapes were not in balance, and readily spoiled, but wine
nevertheless.
Beneath the apparent simplicity, the evolution of grapes into wine is a
series of complex biochemical reactions. Thus winemaking can be as
simple or as complex as you wish to make it. The more you understand and
control the process, the better the wine. The following instructions
cover only the essentials of sound home winemaking.
Under Federal law the head of a household may make up to 200 gallons of
wine a year for family use, but is first required to notify the Treasury
Department’s Bureau of Alcohol, Tobacco and Firearms on Form 1541.
Making Red Wine
The grape constituents which matter most to the winemaker are (a) sugar
content of the juice, and (b) tartness or “total acidity” of the juice.
Sugar content is important because the amount of sugar determines
alcoholic content of the finished wine. A sound table wine contains
between 10% and 12½% alcohol. The working rule is that 2% sugar yields
1% of alcohol. Example: a sugar content of 22% yields a wine of
approximately 11% alcohol.
California grapes normally contain sufficient sugar. Grapes grown
elsewhere are often somewhat deficient, and the difference must be made
up by adding the appropriate amount of ordinary granulated sugar which
promptly converts to grape sugar on contact with the juice.
Sugar Correction Table
What the For wine of 10% by For wine of 12% by
saccharometer shows volume, add volume, add
Ounces of sugar per gallon
10 11.8 16.2
11 10.1 14.8
12 8.9 13.3
13 7.4 11.9
14 5.9 10.4
15 4.6 8.9
16 3.0 7.5
17 1.5 6.0
18 4.3
19 2.9
20 1.4
_Note_: The result is not precise, yield of alcohol varying under the
conditions of fermentation.—
Adapted from _Grapes Into Wine_ by Philip M. Wagner.
In using non-California grapes, you need to test the sugar content in
advance. That is done by a simple little instrument called a
saccharometer, obtainable at any winemakers’ shop. This is floated in a
sample of the juice, and a direct reading of sugar content is taken from
the scale. The correct amount of sugar to add, in ounces per gallon of
juice, is then determined by reference to the sugar table.
[Illustration: Saccharometer and hydrometer jar. Instrument floats
at zero in plain water. It floats higher according to sugar content
of grape juice.]
If _total acidity_, or tartness, is too high and not corrected, the
resulting wine will be too tart to be agreeable. Again, California
grapes are usually within a satisfactory range of total acidity. Grapes
grown elsewhere are often too tart, and acidity of the juice should be
reduced.
In commercial winemaking this is done with precision.
The home winemaker rarely makes the chemical test for total acidity but
uses a rule of thumb. He corrects the assumed excess of acidity with a
sugar solution consisting of 2 pounds of sugar to 1 gallon of
water—adding 1 gallon of the sugar solution for every estimated 4
gallons of juice. This sugar solution is in addition to the sugar
required to adjust sugar content of the juice itself.
In estimating the quantity of juice, another practical rule is that 1
full bushel of grapes will yield approximately 4 gallons. The winemaker
therefore corrects with 1 gallon of sugar solution for each full bushel
of crushed grapes.
The pigment of grapes is lodged almost entirely in the skins. It is
during fermentation “on the skins” that the pigment is extracted and
gives red wine its color.
_How to proceed._ Crush the grapes directly into your fermenter (a clean
open barrel, plastic tub or large crock, never metal). Small hand
crushers are available, but the grapes may be crushed as effectively by
foot—wearing a clean rubber boot. Then remove a portion of the stems,
which may otherwise give too much astringency to the wine.
Low-acid California grapes are quite vulnerable to bacterial spoilage
during fermentation. To prevent spoilage and assure clean fermentation,
dissolve a bit of potassium metabisulfite (known as “meta” and available
at all winemakers’ shops) and mix it into the crushed mass. Use ¼ ounce
(⅓ of a teaspoonful) per 100 pounds of grapes.
[Illustration: Kevin Hayes
A hand-crank grape crusher.]
Also use a yeast “starter”. This comes as a 5 gram envelope of
dehydrated wine yeast, also obtainable at winemakers’ shops. To prepare
the starter, empty the granules of yeast into a shallow cup and add a
few ounces of warm water. When all the water is taken up, bring it to
the consistency of cream by adding a bit more water. Let stand for an
hour, then mix it into the crushed grapes.
After the meta and yeast are added, cover the fermenter with cloth or
plastic sheeting to keep out dust and fruit flies, and wait for
fermentation.
If non-California grapes are used, test and make the proper correction
for sugar content. Then correct the total acidity by adding sugar
solution as described earlier. In using non-California grapes, it is
desirable, but not necessary at this point, to add a dose of meta. A
yeast starter is advisable.
As fermentation begins, the solid matter of the grapes will rise to form
a “cap”. Push this down and mix with the juice twice a day during
fermentation, always replacing the cover.
When fermentation begins to subside and the juice has lost most of its
sweetness, it is time to separate the turbid, yeasty and rough-tasting
new wine from the solid matter. For this purpose a press is necessary,
preferably a small basket press though substitutes can be devised.
Be ready with clean storage containers for the new wine, several plastic
buckets, and a plastic funnel. The best storage containers for home
winemaking are 5-gallon glass bottles or small fiberglass tanks.
Beware of small casks and barrels for several reasons. They are usually
leaky. They are sources of infection and off-odors that spoil more
homemade wine than any other one thing. And there is frequently not
enough new wine to fill and keep them full. Wine containers must be kept
full; otherwise the wine quickly spoils. Using glass containers, you can
see what you are doing.
With the equipment assembled, simply bail the mixture of juice and solid
matter into the press basket. The press basket serves as a drain, most
of the new wine gushing into the waiting buckets and being poured from
them into the containers. When the mass has yielded all its “free run”,
press the remainder for what it still contains.
Fill the containers _full_, right into the neck. Since fermentation will
continue for awhile longer, use a stopper with a fermentation “bubbler”
which lets the gas out but does not let air in. When the bubbler stops
bubbling and there are no further signs of fermentation, replace it with
a rubber stopper or a cork wrapped in waxed paper.
[Illustration: Fermentation bubbler fitted to jar. Left, water is
poured in to level shown. Right, position of water immediately
before a gas bubble passes through.]
Store the wine for several weeks at a temperature of around 60° F.
Suspended matter in the wine will begin to settle, and at this
temperature certain desirable reactions continue to take place in the
wine itself.
At the end of this period, siphon the wine from its sediment, with a
plastic or rubber tube, into clean containers. At the same time dissolve
and add a bit of the meta already referred to at the rate of ¼ level
teaspoon per 5 gallons of wine. This will protect against off odors and
spoilage but does not otherwise affect the wine.
Clarifying
Next, transfer the containers to a place where the wine will be
thoroughly chilled, even down to freezing. This precipitates more
suspended matter and unwanted ingredients, and encourages clarification.
Assuming that the wine was made in early fall, hold it in cool storage
until after the first of the year. By then it should have “fallen
bright” and be stable. To test its clarity, hold a lighted match behind
the bottle.
The wine is then siphoned once again from its sediment, and another dose
of meta added at the same rate of ¼ teaspoon per 5 gallons.
If the wine is brilliantly clear, one container of it may then be
siphoned into wine bottles, corked or capped, and is ready for immediate
use. Despite the common impression, most wine does not gain greatly by
aging once it is stable. It continues to evolve, but not necessarily for
the better.
The rest of the wine is held until after the return of warm weather to
make sure there will be no resumption of fermentation, which would blow
corks if the wine was bottled. By mid-May that hazard will have passed,
and the wine is ready for its final siphoning, its final dose of the
same quantity of meta, and bottling.
_Fining._ If in January the wine is not brilliantly clear, it should be
“fined”. This consists of dissolving in a small amount of hot water and
mixing in, at the time of siphoning, ordinary household gelatin at the
rate of ¼ ounce (2 teaspoonsful) per 5 gallons. This will turn the wine
milky when mixed in and will slowly settle, dragging all impurities and
suspended matter with it. In two weeks to a month the process of
“fining” will be complete. The wine is then ready to be siphoned from
the fining sediment and treated as above.
Making White Wine
As we have seen, red wine is fermented “on the skins” in order to
extract the coloring matter and other ingredients lodged in the skins.
In making white wine, the grapes are crushed and the fresh juice
immediately separated by pressing so that it may ferment apart from the
skins.
This fresh juice is checked for its sugar content and acidity, as in
preparing to ferment red wine, and the proper corrections are made
immediately after pressing. Likewise, a yeast “starter” is added.
The fermentation takes place in the same 5-gallon glass containers that
are later used for storage. But as fermenters they are filled only
two-thirds full as a precaution against any overflow or unmanageable
formation of bubbles.
When the primary fermentation has run its course, the several
partly-filled bottles are simply consolidated—filled full and equipped
with bubblers. Subsequent siphoning from sediment, chilling, and dosing
with meta are carried out as with red wine.
If fining is necessary, it differs in one respect: before mixing in the
gelatin, mix in an equal amount of dissolved tannic acid to remove the
impurities. Tannic acid is obtainable at drug stores or winemakers’
shops as a powder. This provides better settling out of suspended
matter.
Dry table wine is a food beverage, to be used with meals. Sweet wines
are more like cordials.
The making of sweet wines takes advantage of a characteristic of the
yeast organism, namely, that its activity dies down and it usually
ceases to ferment sugar into alcohol after a fermenting liquid reaches
an alcoholic content of around 13%. The secret, then, is to add an
excess of sugar when correcting the juice of crushed grapes before
fermentation. When fermentation ceases, there is still some residual
sugar in the juice. From then on the still-sweet new wine is treated
much as other wine.
The three important differences are: (1) the wine is siphoned from its
sediment immediately after fermentation, without the waiting period at
60° F; (2) the chilling begins as soon as possible; and (3) the dose of
meta added then and at each subsequent siphoning is doubled (½ teaspoon
per 5 gallons instead of ¼ teaspoon) to guard against spoilage and
against any accidental resumption of fermentation.
Dry table wines made from other fruits are rarely successful, but
agreeable sweet wines may be made from them. The point to remember is
that most fruits are lower in sugar than grapes and higher in acid.
Corrections for both are almost always necessary, plus sufficient excess
sugar to leave residual sweetness after fermentation.
These fruits, with the exception of apple juice, are fermented in a
crushed mass in order to obtain a maximum extraction of characteristic
odors and flavors. Once fermentation is concluded, they are treated like
sweet grape wine. The table will serve as a rough guide to their
relative sugar content and total acidity.
Making Sweet Wine
Fruit Average Sugar needed Average acid Gallons of
sugar per gallon to sugar water[]
level make a sweet to add per
wine gallon
ounces
Grapes (eastern) 12-20 1¼-2 med. to high 0-1
Grapes (Calif.) 16-20 1-1½ low[] to med. 0
Apples 13 2-2¼ low[] to high 0-½
Apricots 12 2-2½ med. to high 0-¼
Blackberries 6 2-3 high to very high 1 or more
Blueberries 8 2¼-3 low to med. 0
Cherries (sour) 14 2-2¼ high to very high 1 or more
Cherries (sweet) 18 1½-2 medium 0
Pear 12 2¼-2½ med. to high 0-¼
Plum (Damson) 14 2-2¼ med. to high 0-¼
Plum (Prune) 17 1½-2 med. to high 0-¼
Peach 10 2-2½ med. to high 0-¼
Raspberries 8 2½-3 high to very high 1 or more
Strawberries 5 2-3¼ med. to high 0-½
[C]To maintain proper sugar level when the acidity is reduced by adding
water, it is easier to make up a sugar solution by dissolving 3
pounds of sugar in enough water to fill a 1-gallon jug.
[B]Addition of some acid (citric or tartaric) may help. This can be done
“to taste” after the active fermentation is over.
Vinegar
If a cork happens to pop out unnoticed and air reaches the wine for
several weeks, there is a good chance that bacterial action will begin
to convert the alcohol in the wine into acetic acid. Once the presence
of acetic acid can be detected (a vinegar-like odor) the wine will lose
its appeal as wine. A usable vinegar can be retrieved by encouraging the
process to go to completion.
Vinegar produced from an undiluted wine will be overly strong, so an
equal volume of water should be added. The container should be less than
three-quarters full and closed with a loose cotton plug or covered with
a piece of light cloth to keep out fruit flies.
If wine vinegar is your desired goal and no wine has started to sour,
use a vinegar starter. A selected strain of vinegar starter can be
purchased from some winemakers’ shops, or a wild starter may be used.
Frequently the water in an air-bubbler will have a vinegar-like smell.
This can be used to start a batch of vinegar. The wine is diluted with
an equal volume of water and the container partly filled and covered as
above.
A warm, but not hot, location will speed the process. In a month or two
the vinegar should be ready. The clear portion of the vinegar can be
poured or siphoned off for use. If another batch is wanted, more of the
wine-water mixture can be added to the old culture.
Home Drying of Fruits and Vegetables
_by Dale E. Kirk and Carolyn A. Raab_[16]
Tasty ready-to-eat snacks and confections are some of the versatile
products you can create by drying fruits and vegetables at home. After
soaking in water, the rehydrated food can be used in favorite recipes
for casseroles, soups, stews and salads. Rehydrated fruits and berries
can also make excellent compotes or sauces.
Drying is appealing because the procedure is relatively simple and
requires little equipment. Only minimal storage space is needed. Food
can be dried in the sun, in the oven, or in a dehydrator.
Drying requires a method of heating the food to evaporate the moisture
present, and some means of removing the water vapor formed.
Sun drying utilizes both radiant heat energy and heat transferred to the
product from warm air. Natural air currents are usually adequate to
carry away the water vapor.
Trays of wood slats, plastic mesh, or aluminum screen may be placed in
the sun on support blocks or strips to allow air movement around and
through the trays. Galvanized wire is not recommended as a tray material
because high-acid foods will react with the zinc coating on the steel
wire.
If insects or birds are a problem, a wooden frame can be constructed
over the trays to support a plastic mesh or cheesecloth cover. Further
protection can be provided by using a totally enclosed frame and a
transparent panel to form a solar drying oven.
To dry in the kitchen oven, the thermostat should be set to its lowest
temperature (generally about 150° F). Since oven vents provided for
removing moisture from roasting and baking are adequate for drying only
small quantities of food at one time, the oven door should be left
partially opened. For larger loads, the air circulation rate can be
increased by placing a household fan outside the oven, directed at one
edge of the partially opened oven door.
Dehydrator cabinets may be purchased in many sizes and types. Or they
may be built using plans available from State universities or U.S.
Department of Agriculture plan services (ask your county Extension
office about plans). All cabinets are provided with a heat source and
vents for carrying off moist air.
Simpler units may rely on natural convection to carry moist air away,
and the heating unit may be limited in output so that the cabinet never
exceeds safe drying temperatures near the end of the drying period. This
type will be slow in achieving drying temperature if sizable amounts of
food are processed at one time.
Trays must be rotated during the processing period to insure even
drying. Trays nearest the bottom, exposed to the hottest, driest air,
will dry most rapidly.
If the natural convection type cabinet is equipped with a thermostat, it
may be fitted with a larger heater. This will provide higher drying
temperatures during the early stages but will not give even drying
across all trays.
By using a fan to force air across the trays more rapidly, even drying
can be obtained across each tray as well as between trays. The forced
air system may be used with or without a thermostat.
Most food products release moisture rapidly during early stages of
drying. This means they can absorb large amounts of heat and give off
large quantities of water vapor while remaining at a temperature well
below that of the drying air. Maximum drying rates can be achieved by
providing a larger, thermostatically-controlled heat source and a fan
for circulating air.
[Illustration: Enclosed frame solar drying oven with provision for
air movement.]
air in (screened)
trays
glass or transparent plastic
air out (screened)
[Illustration: Dehydrator with built-in heater relies on air
movement to carry off moist air.]
air in
heating element
heat shield
trays
air out
[Illustration: This forced draft dryer can recirculate much of the
drying air to conserve energy.]
air in
fan
heaters
heat shield
thermostat
trays
air out
To conserve energy and still obtain rapid, even drying across all trays,
much of the drying air may be reheated and recirculated. This is
particularly effective during the last 70% to 90% of the drying period,
when relatively small amounts of water are absorbed by the air as it
passes over the partially dried food.
The recirculating system requires either a thermostat or separate switch
controls on part of the heating unit to adjust heat output to match the
drying load. The amount of air recirculated is determined by the size of
the permanent inlet and outlet openings in the box. It can be further
controlled by adjusting the door to a partially opened position.
Detailed plans for constructing the recirculation-type drier can be
obtained by sending 25¢ to the Western Regional Agricultural Engineering
Service (WRAES), Oregon State University, Corvallis, Oreg. 97331 and
requesting WRAES Fact Sheet No. 18.
Procedure
Drying is a relatively simple process, but there are a number of
recommended techniques. You may need to use a “trial and error” approach
to find the drying procedure which works best in a particular situation.
Fruits and vegetables can be dried in pieces or pureed and dried in a
thin sheet as a “leather.”
The following information summarizes major steps in drying. Detailed
instructions are available at county Extension offices. Also, various
books on the market give instructions for drying and recipes for using
dried food.
Fruits and vegetables selected for drying should be the highest quality
obtainable—fresh and fully ripened. Wilted or inferior produce will not
make a satisfactory dried product. Immature produce lacks flavor and
color. Overmature produce may be tough and fibrous or soft and mushy.
Steps in Drying Fruits and Vegetables
PREPARE
wash, sort
peel, pit/core, slice
PRETREAT
fruits: dip or blanch
vegetables: blanch
DRY
oven, sun, dehydrator
CONDITION AND STORE
equalize, pasteurize
package and store
Prepare produce immediately after gathering, and begin drying at once.
Wash or clean all fresh food thoroughly to remove any dirt or spray.
Sort and discard defective food; decay, bruises, or mold on any piece
may affect an entire batch.
For greater convenience when you finally use the food, and to speed
drying, it is advisable to peel, pit, or core some fruits and
vegetables. Smaller pieces dry more quickly and uniformly.
Pretreating
Enzymes in fruits and vegetables are responsible for color and flavor
changes during ripening. These changes will continue during drying and
storage unless the produce is pretreated to slow down enzyme activity.
Blanching is the recommended pretreatment for vegetables. It helps save
some of the vitamin content, sets color, and hastens drying by relaxing
tissues. Blanching may also prevent undesirable changes in flavor during
storage, and improve reconstitution during cooking.
Steam blanching is preferred because it retains more water-soluble
nutrients than water blanching. Blanching times differ, depending on the
type of vegetable being dried. Overblanching leads to excessive leaching
of vitamins and minerals. Inadequate blanching will not destroy enzymes
that cause vitamin loss during drying and storage.
Many light-colored fruits (especially apples, apricots, peaches,
nectarines, and pears) tend to darken during drying and storage. To
prevent this darkening, the fruit may be pretreated by blanching or by a
suitable dip, but effectiveness of pretreatment methods varies.
Fruit may be dipped in one of the following:
—A solution of table salt
—A solution of ascorbic acid. Commercial antioxidant mixtures
containing ascorbic acid may also be used, but often are
not as effective as pure ascorbic acid.
Fruits may be steam-blanched. However, blanched fruits may turn soft and
become difficult to handle.
Sirup blanching may help retain the color of apples, apricots, figs,
nectarines, peaches, pears and plums. A sweetened candied product will
result.
Fruits with tough skins (grapes, prunes and small dark plums, cherries,
figs, and some berries) may be water-blanched to crack the skins. This
will allow moisture inside to surface more readily during drying.
Before drying pretreated food, remove any excess moisture by placing the
food on paper towels or clean cloths. Drying trays should be loaded with
a thin layer of food as directed. If needed, clean cheesecloth can be
spread on the trays to prevent food pieces from sticking or falling
through.
The amount of food being dried at one time should not exceed that
recommended by instructions.
Drying
A temperature of 135° to 140° F is desirable for dehydrator and oven
drying. Moisture must be removed from the food as fast as possible at a
temperature that does not seriously affect the food’s flavor, texture,
color, and nutritive value.
If the initial temperature is too low or air circulation insufficient,
the food may undergo undesirable microbiological changes before it dries
adequately.
If the temperature is too high and the humidity too low, as when drying
small loads in the oven, the food surface may harden. This makes it
difficult for moisture to escape during drying.
Oven or dehydrator drying should continue without interruption to
prevent microbial growth.
To promote even drying, rotate trays occasionally and stir food if
necessary.
Drying time varies according to fruit or vegetable type, size of pieces,
and tray load. Dehydrator drying generally takes less time than oven
drying. Sun drying takes considerably more time.
Before testing foods for desired dryness, remove a handful and cool for
a few moments. Foods that are warm or hot seem softer, more moist, and
more pliable than they will when cooled.
Foods should be dry enough to prevent microbial growth and subsequent
spoilage. Dried vegetables should be hard and brittle. Dried fruits
should be leathery and pliable. For long term storage, home dried fruits
will need to be drier than commercially dried fruits sold in grocery
stores.
Conditioning and Storing
Fruits cut into a wide range of sizes should be allowed to “sweat” or
condition for a week after drying to equalize the moisture among the
pieces before placing in long term storage. To condition, place fruit in
a non-aluminum, non-plastic container and put in a dry, well-ventilated
and protected area. Stir the food gently each day.
Dehydrated foods are free of insect infestation when removed from the
dehydrator or oven. However, sun-dried foods can be contaminated and
should be treated before storage. Insects or their eggs can be killed by
heating dried food at 150° F for 30 minutes in the oven. An alternative
is to package the food and place it in the home freezer for 48 hours.
Dried foods should be thoroughly cooled before packaging. Package in
small amounts so that food can be used soon after containers have been
opened.
Pack food as tightly as possible without crushing into clean, dry,
insect-proof containers. Glass jars or moisture-vapor proof freezer
cartons or bags (heavy gage plastic type) make good containers. Metal
cans with fitted lids can be used if the dried food is first placed in a
plastic bag.
Label packaged foods with the packaging date and the type of food.
Store containers of dried foods in a cool, dry, dark place. Check food
occasionally to insure that it has not reabsorbed moisture. If there is
any sign of spoilage (off-color or mold growth), discard the food. Food
affected by moisture, but not moldly, should be used immediately or
re-heated and repackaged.
All dried foods deteriorate to some extent during storage, losing
vitamins, flavor, color, and aroma. However, low storage temperatures
prolong storage life, and dried foods may be frozen for long term
storage.
Dried foods can be reconstituted by soaking, cooking, or a combination
of both, and will resemble their fresh counterparts after
reconstitution. However, dried foods are unique and should not be
expected to resemble a fresh product in every respect.
Drying does not render the food free of bacteria, yeasts, and molds.
Thus, spoilage could occur if soaking is prolonged at room temperature.
Refrigerate if soaking for longer than 1 to 2 hours.
To conserve nutritive value, use the liquid remaining after soaking and
cooking as part of the water needed in recipes.
One cup of dried vegetables reconstitutes to about 2 cups. To replace
the moisture removed from most vegetables, barely cover them with cold
water and soak 20 minutes to 2 hours. Cover greens with boiling water.
To cook, bring vegetables to a boil and simmer until done.
One cup of dried fruit reconstitutes to about 1½ cups. Add water just to
cover the fruit; more can be added later if needed. One to eight hours
are required to reconstitute most fruits, depending on fruit type, size
of pieces, and water temperature. (Hot water takes less time).
Over-soaking will produce a loss of flavor. To cook reconstituted fruit,
cover and simmer in the soak water.
Dried or reconstituted fruits and vegetables can be used in a variety of
ways.
Use dried fruit for snacks at home, on the trail, or on the ski slopes.
Use pieces in cookies or confections.
Serve reconstituted fruit as compotes or as sauces. It can also be
incorporated into favorite recipes for breads, gelatin salads, omelets,
pies, stuffing, milkshakes, homemade ice cream and cooked cereals.
Add dried vegetables to soups and stews or vegetable dishes. Use as dry
snacks or dip chips.
Include reconstituted vegetables in favorite recipes for meat pies and
other main dishes, as well as gelatin and vegetable salads.
Powdered vegetables in the dried form make a tasty addition to broths,
raw soups, and dressings.
Some vitamin breakdown occurs during drying and storage of dried fruits
and vegetables. Ascorbic acid (Vitamin C) is the vitamin most likely to
be lost.
Nutritive losses can be kept to a minimum by:
—Blanching the correct length of time
—Packaging dried foods properly and storing containers in a cool, dry,
dark place
—Checking dried foods periodically during storage to insure that
moisture has not been reabsorbed
—Eating dried foods as soon as possible
—Using liquid remaining after reconstitution in recipes
Storage of Home-Preserved Foods
_by Ralph W. Johnston_[17]
Proper storage of home-preserved foods, especially of home-canned
products, and close scrutiny before serving are essential. If proper
storage requirements are not met, home-preserved foods may lose their
quality or spoil.
Homemakers should observe some simple techniques for checking
home-canned foods before serving them. This will help prevent
consumption of food that could cause the rare but extremely dangerous
food poisoning called botulism.
Most canned foods are highly perishable yet do not require refrigeration
until opened. Unlike frozen foods, they are unaffected by power
interruptions or mechanical failures.
However, the hazard of botulism must always be kept in mind. Although
botulism is rare, it results in a high death rate of about 65 percent
among its victims. Yet it is an easy problem to avoid. Botulism results
when home-canned foods are improperly processed. Under these conditions,
the spore (a seed-like structure which is highly heat-resistant) of a
soil bacterium called _Clostridium botulinum_ may survive.
If the food product is low in acidity, as with peas, corn, or beans, the
spore can germinate (sprout) and grow during storage at room
temperatures. As _Clostridium botulinum_ grows, it produces a powerful
poison that when ingested can cause severe illness or death. Most cases
of botulism in the United States stem from home-canned foods.
The home canner can avoid botulism primarily by following prescribed,
reliable processing instructions such as those given in USDA Home and
Garden Bulletin No. 8, _Home Canning of Fruits and Vegetables_. If you
don’t have reliable processing instructions, don’t attempt home canning.
If you have these instructions, read them before and during home canning
and do not take short cuts or modify the instructions.
Do not use processing instructions of neighbors or relatives; although
frequently given with the best of intentions, they may contain
modifications that are inadequate and dangerous. Remember that past safe
history of a relative’s processing procedure is no guarantee of future
safety. Botulism doesn’t always occur even in inadequately processed
home-canned foods.
After home-canned foods have cooled they are ready to be stored until
needed. At this point, the home canner should make his first quality
control and safety check, just as commercial canners do.
Jar lids should be examined. If the center of the lid is not depressed
or is loose, refrigerate the product immediately and serve at the next
meal. Before serving, boil low acid products for 10 minutes. Check all
jars for cracks; if they are found, treat jars the same way as those
with loose lids.
Observe cans for any evidence of leakage around seams; again if leakage
is observed, refrigerate the cans immediately, serve at the next meal,
and boil for 10 minutes before serving.
During this first integrity check on home-canned foods, it is unlikely
that swelling of the cans or foaming in the jars will be noticeable,
because of the short lapse of time since processing. But the first check
can easily detect loose lids, cracked jars and leaking seams on cans.
The next step is to store home-canned products. Proper storage will
protect the products from loss of quality and in some cases from
spoilage. Store canned foods in a clean, cool, dry area away from bright
light—particularly sunlight—and in an area where the foods will not
freeze or be exposed to high temperatures. Under these conditions, the
products will remain at high quality for at least a year.
Excessive dampness will rust cans or metal lids. If this condition
becomes severe, leakage will occur and the product will spoil. Freezing
causes expansion of the product and the jar lid may loosen, the jar may
crack, or can seams may be stressed. This can lead to leakage and food
spoilage.
When foods are preserved by heating, as in home canning or commercial
canning, the heating process is designed to destroy all normal spoilage
bacteria that can grow under usual storage conditions, and all bacteria
capable of causing human harm. The products are called “commercially
sterile” but are not always truly sterile.
A group of bacteria produce extremely heat-resistant spores that can
only germinate and grow at high storage temperatures such as those above
103° F. These bacteria often survive both the home and commercial
canning process. Even though present, they normally are of little
concern from the viewpoint of spoilage and no concern at all from the
standpoint of human health. However, if canned foods are stored in
attics or near hot water pipes or in any other area where the
temperature will exceed 102° F at any time, these heat-loving bacteria
(called thermophilic) can grow and spoil the product.
[Illustration: Fred Farout
Boil home-canned low-acid foods 10 minutes before tasting or
serving.]
As a rule of thumb, home-canned foods will remain high in quality for
one year if properly stored. After a year, loss of quality may occur.
Containers for home-preserved foods are designed to resist any chemical
reactions between the product and the containers. However, some
products—particularly high acid ones like tomatoes—will slowly react
with the metal in the can or the jar lid. Corrosion and container
failure may follow during subsequent storage. This action occurs from
the inside out and can take place even under good storage conditions.
Jars should be dated when stored, and used within a year from the
processing date. Always rotate stock on the shelves so as to use the
oldest container first, and can no more units of any single product than
you can use in a year.
The last and perhaps most important quality control steps are the final
inspection and serving procedures.
After removing the product from storage, carefully inspect the
container, and in the case of jars the visible contents. This should be
done before opening.
If a can or jar lid shows any sign of swelling (bulging) or leakage of
product, do not open the container. If a jar lid is loose or the
contents of a jar are foamy or otherwise visibly abnormal, do not open.
When any of these defects are noted, place the whole container in a
heavy plastic bag and tie the top securely. Place this in doubled paper
bags with heavy packing of newspapers. Tape or tie the top securely,
place in a lidded garbage can, then wash your hands thoroughly.
Not all spoiled or leaking home-canned foods contain the deadly botulism
toxin but some do, so extreme caution in disposal is necessary.
If a defective product is found, all of that product prepared at the
same time should be removed from storage and similarly inspected.
Never taste the contents of a suspect product. Under certain
circumstances, a spoonful of “off” unheated, suspect product has been
known to kill.
Finally, bring all home-canned vegetables to a rolling boil after
opening and before tasting. Heating makes any odor of spoilage more
noticeable. Again, if an odor of spoilage is noted, destroy the product
with caution. If the product is normal, cover the pan and continue to
boil at least 10 minutes before serving. Only after these precautions
are taken are home-canned vegetables safe to taste and serve.
Home Frozen Foods
A plus for home freezing is that slight variations in following
directions do not result in a botulism hazard. The bacterium that causes
botulism cannot grow in the freezer. Proper freezing prevents the growth
of microorganisms that cause spoilage and those that can cause illness.
Besides the initial cost of the freezer itself, energy costs are
significant. Utilize the freezer fully to keep the energy costs per unit
as low as possible. Fill the freezer when foods are least expensive, use
the products as needed, and be careful to use the oldest products first.
Take care not to overload the freezer. If you pack it too tightly with
containers of warm food, the freezer will be unable to remove the heat
fast enough and spoilage from bacterial growth can result.
To avoid this, freeze foods soon after they have been packed; put no
more unfrozen food into a home freezer than will freeze within 24 hours.
Usually, this will be about 2 or 3 pounds of food to each cubic foot of
capacity.
For quickest freezing, place packages against freezing plates or coils
and leave a little space between packages so air can circulate.
Small excesses of product destined for freezing can be held in the
refrigerator until the first load is frozen. If a large excess of
product exists, chill and carry it in an insulated box or bag as soon as
possible to a locker plant.
After freezing, packages may be stored close together. Store them at 0°
F or below in order to retain the highest quality for the longest time.
Prolonged storage of frozen foods results in slow loss of quality. The
rate of this loss differs with various foods. To maintain high quality,
obtain information on recommended storage periods for the foods you
freeze. This may be obtained from your county Extension office or from
USDA Home and Garden Bulletin No. 10, _Home Freezing of Fruits and
Vegetables_.
Storage periods are recommended to guarantee food quality only. If these
periods are exceeded, taste may be affected but as long as the product
has been kept at 0° F or below there is no question of safety.
The homemaker’s greatest concern with a home freezer is mechanical or
power failure, which can result in food losses. Some but not all of
these can be avoided. Freezers are very dependable mechanical devices
yet they do fail. Most failures develop after 5 or more years of use.
The homeowner should clean dust from coils of the freezer once or twice
each year in strict accordance with the instruction manual for the unit.
At this time watch for any changes that have occurred. Have a dealer or
repairman check unusual noises or excessive running.
Air circulation around the coils should not be covered or blocked in any
way. Check the plug itself for a firm fit. If the plug is loose in the
receptacle, it may fall or be easily bumped out without notice. Replace
loose plugs. Better yet, some hardware stores sell clips that clamp the
plug in by means of the screw that holds the receptacle plate onto the
outlet.
Freezer owners should know where the closest commercial freezer is, in
case of an extensive failure. Check your home freezer after
thunderstorms or power failures, since freezers have been known to be
damaged occasionally when power falls or surges.
Don’t Open
A well packed freezer will hold the product for many hours even if the
unit is not operating. Normally, power failures are short in duration
and no food thawing results. If the power is off, do not open the
freezer as this will hasten thawing. Telephone or otherwise determine
when the power will be turned on again.
Sometimes freezer failure is discovered only when a homemaker goes to
the freezer to get something. If this occurs, condition of the food
should be determined immediately. Discard all foods that are thawed and
warm, since extensive bacterial growth may have taken place.
Foods may be saved if they remain frozen; or if they are thawed but very
cold, about 40° F, and have been held no longer than 1 or 2 days at
refrigerator temperatures after thawing. Bacteria grow only slowly in
thawed but cold foods. Prompt refreezing of thawed cold foods will lower
the quality but not result in spoilage or danger. If you have doubt as
to whether the foods are cold or warm, throw them out as the safest
course.
Once condition of the foods is determined, plan fast for the next step.
If the freezer cannot be repaired quickly, make arrangements to move the
food to a commercial locker plant or another freezer. To do so, package
the products closely together in paper bags. Place these in cardboard
cartons lined and covered with newspapers for insulation, and transfer
them immediately.
Another way to save the freezer load is to use dry ice in the freezer
itself. Dry ice must be handled with gloves to prevent burns. Also keep
in mind that carbon dioxide gas evolves as dry ice evaporates, and can
cause unconsciousness if allowed to concentrate.
When transporting dry ice, leave a car window open at least several
inches. If you use dry ice in the freezing compartment, make sure a
nearby window is cracked open. When packing dry ice into a freezer,
figure on 25 to 50 pounds to do the job. Don’t break up the ice any more
than necessary.
To summarize, frozen foods are seldom involved in food spoilage or food
poisoning. Even so, mechanical devices occasionally fail, and freezer
owners should have prearranged plans for such an emergency. Preventive
maintenance will help reduce the likelihood of failure. If a failure
results in food becoming thawed and warm, discard it for safety.
Storing Fresh Fruit and Vegetables
_by Anton S. Horn and Esther H. Wilson_[18]
Many fruits and vegetables can be stored fresh. But the home gardener
must gather them at proper maturity and observe correct temperature,
humidity, ventilation, and cleanliness rules.
Basements or outdoor cellars can serve as temporary storage for some
produce. A cellar mostly below ground is best for root vegetables. It
can be run into a bank and covered with 2½ feet or more of soil.
Sometimes outdoor root cellars are made with a door at each end.
Combining the outdoor storage cellar with a storm shelter in the event
of tornadoes or other needs may be a satisfactory solution.
Modern basements are generally too dry and warm for cool moist storage.
However, a suitable storage room may be built by insulating walls and
ceiling and ventilating through a basement window. You may ventilate by
extending a ventilating flue from half of the window down almost to the
floor. Cover the other half of the window with wood and the outside
openings of the ventilator with a wire screen for protection against
animals and insects.
Keep the room cool by opening the ventilators on cool nights and closing
them on warm days. If properly cooled, the room temperature can be
controlled between 32° and 40° F during winter. To maintain the
humidity, sprinkle water on the floor when produce begins to wilt. A
slatted floor and slatted shelves will provide floor drainage and
ventilation. A reliable thermometer is needed for operation of any home
storage room.
A cool corner in the basement, a back room of a small house with no
basement, or a trailer may be suitable. One lady we know uses part of a
closet built into the outside corner of a bedroom. It is also possible
to adapt storage sheds in carports by insulating and proceeding as
outlined earlier.
Pits and trenches or mounds may be used for storage if a root cellar is
not available or basement storage is impractical. Also, you may bury a
barrel, drainage tile, or galvanized garbage can upright, with four
inches of the top protruding above ground level. This will keep
potatoes, beets, carrots, turnips, and apples through winter. For
convenience, place the produce in sacks or perforated polyethylene bags
of a size to hold enough for a few days. Then you can easily take out
fruits and vegetables as needed.
Place the barrel on a well drained site, and make a ditch so surface
water will be diverted and not run into the container. A garbage can has
a good lid, but for a drainage tile or barrel a wooden lid may have to
be built. The lid should be covered with straw, and a waterproof cover
of canvas or plastic placed over the straw.
Requirements of fruits and vegetables differ. Controlled cold storage or
refrigerated storage are best.
Good references are _Storing Vegetables and Fruits in Basements,
Cellars, Outbuildings, and Pits_, USDA Home and Garden Bulletin No. 119,
and bulletins on this subject prepared by your State Extension service.
Your county Extension office may have the bulletins. This office may
also be able to tell you how to obtain plans for a fruit and vegetable
storage room, or a storm and storage cellar.
Brief notes on specific storage problems follow:
With proper care, hard-rind varieties of winter pumpkins and squash will
keep for several months. Harvest before frost, and leave on a piece of
stem when you cut them from the plants.
Store only well-matured fruits that are free of insect damage and
mechanical injuries.
Pumpkins and squash for long-term storage keep better when cured for 10
days at 80° to 85° F. If these temperatures are impractical, put the
pumpkins and squash near your furnace to cure them. Curing hardens the
rinds and heals surface cuts. Bruised areas and pickleworm injuries,
however, cannot be healed.
After curing pumpkins and squash, store them in a dry place at 55° to
60° F. If stored at 50° or below, pumpkins and squash are subject to
damage by chilling. At temperatures above 60°, they gradually lose
moisture and become stringy.
Acorn squash keep well in a dry place at 45° to 50° F for 35 to 40 days.
Do not cure acorn squash before storing them. They turn orange, lose
moisture, and become stringy if cured for 10 days at 80° to 85° or if
stored at 55° or above for more than 6 to 8 weeks.
A dark green rind at harvest indicates succulence and good quality.
Do not store pumpkins and squash in outdoor cellars or pits.
_Parsnips_, _Salsify_, _Horseradish_ can be left undug (stored) in the
ground.
These vegetables withstand freezing, but alternate freezing and thawing
damages them. If you store them in the ground, mulch lightly at the end
of the growing season. Keep them covered until outdoor temperatures are
consistently low. Then remove the mulch to permit thorough freezing.
After they have frozen, mulch deep enough to keep them frozen.
[Illustration: Some fruits and vegetables can be stored outdoors in
a partially buried galvanized garbage can or wooden barrel.]
waterproof cover
straw
drainage ditch
garbage can or wooden barrel
Root Crops
Root crops such as beets, carrots, celeriac, kohlrabi, rutabagas,
turnips, and winter radishes should not be put in storage until late
fall. Root crops keep best between 32° and 40° F. They require high
humidity to prevent shriveling. Continued storage at 45° causes them to
sprout new tops and become woody.
Large and overmature root crops may become tough and stringy in storage.
Small and immature root crops probably will shrivel.
Dig root crops when the soil is dry and the temperature consistently
low. Prepare them immediately for storage. Cut the plant tops about a
half inch above the crown. Beets will bleed unless 2 to 3 inches of the
top is left. You may wash the roots if you let them dry again before
storing. Do not expose them to drying winds, and be sure they are cool
when put in storage.
Prevent bitterness in carrots by storing them away from fruits such as
apples, which give off volatile gases while ripening.
Turnips and rutabagas give off odors, so don’t store them in your
basement. Find a separate spot, or store them with other root crops and
vegetables in an outdoor cellar or pit. Turnips may be left in the
garden longer than most other crops. They withstand hard frosts, but are
damaged by alternate freezing and thawing. All other root crops can be
stored together in your basement storage room.
[Illustration: VEGETABLE-FRUIT STORAGE GUIDE]
Low Humidity
80-85 cure pumpkins, squash
55-60 pumpkins, squash
45-50 acorn squash
32 onions
High Humidity
80-85 cure sweet potatoes
70 mature green tomatoes—to ripen
55-60 tomatoes at mature green stage—to store sweet
potatoes
45-48 potatoes for highest quality
38-40 potatoes—to prevent sprouting
32-40 beets, celeriac, kohlrabi, turnips, carrots,
rutabaga
30-32 apples, pears
Root crops keep their crispness longer when bedded in layers of moist
sand, peat, or sphagnum moss. However, perforated polyethylene bags and
box liners are easier to use than bedding. Root crops can be stored in
crates or boxes in moist air, but they gradually lose moisture and
quality unless polyethylene liners are used. Carrots and beets may be
stored in 10-gallon crocks or any container that will prevent excessive
shriveling.
Quick dipping of dried and trimmed turnips, rutabagas, or parsnips in
wax will prevent shriveling. Float a layer of jelly-type paraffin on top
of a kettleful of heated water which is deep enough to cover the
vegetable. Dip room temperature vegetables quickly through the layer of
wax.
For a thinner, harder wax film add a little salt and 10 to 20 percent
clean beeswax.
Potatoes are the principal root crops you will probably store. Potatoes
are eaten from the time they are of sufficient size for early use until
storage time, and during storage when the vines have fully ripened.
If potatoes are harvested before maturity the skin may flake off easily.
They are all right for immediate use, but not for storage. Immature
potatoes shrink badly, bruise easily, and will not keep well very long.
For storage, potatoes should be allowed to mature and develop a thick
skin. When the tops lie down the tubers should be mature enough for
storage.
Dig potatoes carefully to avoid bruises, for better storage life.
Handle newly dug potatoes with care until the surface has dried or cured
a few hours or more. You can keep them in baskets or slatted crates in
single layers at first.
Store sound mature tubers in darkness at a minimum relative humidity of
95 percent and 45° to 48° F for highest quality. For very long storage
keep at a temperature of 38° to 40° to prevent sprouting. The starch
changes to sugar if potatoes are held below 45°. Potatoes may not show
any external effect from exposure to these lower temperatures, but
sometimes darkened tissue will be seen if the potato is cut and exposed
to air.
Light causes considerable “greening” in potatoes. The green portion
contains an undesirable substance that gives a bitter flavor.
Sweet potatoes that are well matured, carefully handled, properly cured,
and stored at 55° to 60° F can be kept until April or May.
Sweet potatoes are easily bruised and cut. Handle them carefully and as
little as possible. Put them directly in storage containers at harvest.
Cure freshly dug sweet potatoes by holding them about 10 days under
moist conditions at 80° to 85° F. In the absence of better facilities,
sweet potatoes can be cured near your furnace. To maintain high humidity
during curing, stack storage crates and cover them with paper or heavy
cloth. If the temperature near your furnace is between 65° and 75°, the
curing period should last 2 to 3 weeks. After curing, move the crates to
a cooler part of your basement or house where a temperature of about 55°
to 60° can be maintained.
In houses without central heating, sweet potatoes can be kept behind a
cookstove or around a warm chimney. If you keep sweet potatoes this way,
wrap them in fireproof paper (to slow down temperature changes) and
store them in boxes or barrels.
Sweet potatoes are subject to damage by chilling. Do not store them at
50° F or below.
Outdoor pits are not recommended for storing sweet potatoes, because
dampness of the pits encourages decay.
Tomatoes
Even though the home canner has canned plenty of tomatoes, it may be
desirable to keep some of the fresh fruit. Keep tomatoes in the garden
as long as possible. You can protect against early fall frosts by
covering the plants with burlap or old carpets in the evening when frost
is predicted. Polyethylene may also be used but injury will occur
wherever it touches the plant.
In the summer, tomatoes should be harvested when fully vine-ripened for
best quality. Pick when the color is a dark red in red varieties. During
fall when frost is likely, mature green fruit can be picked and it will
develop a red color when kept in a fairly warm place. The fruit is in
the “mature-green” state if the tissues are gelatinous or sticky when
the tomato is cut and the tomato interior is yellowish. Immature green
tomatoes don’t ripen satisfactorily.
To check your judgment, cut a tomato in half that you feel is mature
green. If the pulp that fills the compartments is jelly-like, it is
mature green. The seeds are dragged aside easily by the knife and not
cut through. In immature green tomatoes, seeds are easily cut through
and the jelly-like pulp has not yet developed. Usually you can recognize
the mature green ones by their glossiness, less hairiness, and more
whitish green color.
You can pick mature-green fruits and bury them in deep straw or place in
a room where the temperature is 60° to 70° F. The tomatoes will ripen
over a period of 3 or 4 weeks. Sunlight is not needed to ripen
green-ripe tomatoes, so don’t bother to put them on window sills. They
ripen satisfactorily in the dark. Generally, tomatoes store best at 55°
to 60° and ripen at 70° or room temperature.
You can wash the mature green fruits in a weak solution of household
bleach and then wrap in paper to store and ripen.
Some people pull up the vines just before frost and hang them in the
basement or garage to ripen their fruit.
Onions
Harvest onions for storage when the neck of the plant dries down, the
tops have fallen over, and the roots are dry and have stopped growing
from the stem plate. At that time the outer scales of the bulb are
drying out and do not cling tightly (outer scales of yellow-skinned
varieties change to a darker color).
Pull the onions by hand and lay in a windrow to cure with the tops
placed over the bulbs to prevent sun-scald. Onions may also be cured in
an open shed. Remove onions with thick neck (seeders) before storage and
discard all diseased bulbs.
After curing, place onions in open-slatted crates or burlap bags for
further field curing or drying. Then place in storage. You may use
either common storage or refrigerated storage.
Low temperatures in storage reduce shrinkage due to moisture loss and
stop disease development. Keep the humidity as low as possible. Good
management of ventilation is important. Ventilate storage early in the
morning.
Onions held in cold storage should be placed there immediately after
curing. A temperature of 32° F is ideal and will keep onions dormant and
relatively free of rot. If sprouts grow it indicates too high a
temperature, poor curing, or immature bulbs. If you have root growth the
humidity is too high. The humidity should be 65 to 70 percent.
Do not store onions with produce that is likely to absorb the odor.
Onions stand slight freezing, but do not handle or move them until they
thaw. You can store onions in a dry, well ventilated attic or unheated
room. Maintain as near 32° F as you can and keep as dry as possible. You
can hang open-mesh bags, about half full, from overhead hooks or nails.
Slatted half full crates of onions may be stacked on cross bars.
Apples, Pears
Chemical changes take place in the ripening process of apples and pears.
This activity is called respiration. Starch changes to sugar, acids and
insoluble pectins decrease, and volatile gases are given off. This
continues until the fruit becomes overripe and mealy. During this
ripening process oxygen is consumed from the air, and water and carbon
dioxide are produced and heat is generated.
You may slow respiration by cooling fruit as rapidly as possible after
picking. The sooner this is done the longer the fruit will keep.
Research indicates that when apples are stored at 30° F, about 25
percent more time is required for them to ripen than at 32°. Stored at
40°, the rate of ripening is about double that at 32°. At 60° the rate
is close to three times that at 40°, and at 85° the softening and
respiration rates have been found to be about double those at 60°. This
emphasizes the importance of cooling quickly and keeping cold. The
average freezing point of apples is about 28° or 29°.
Most apple varieties keep best at a temperature of 30° to 32° F and a
relative humidity of 85 to 88 percent. However, McIntosh, Yellow Newton,
and Rhode Island Greening apples do best at 35° to 38°. This prevents
internal browning and brown core.
Pears can be stored ideally at 30° to 31° F. The highest freezing point
for pears is about 29°. Since pears are likely to shrivel, keep the
humidity at 90 percent. Most pears won’t ripen satisfactorily for eating
at the above temperatures. They should be taken out of storage and
ripened between 65° and 70°. This is ideal for Bartletts.
Bartlett pears ripen faster than apples. If you store pears too long
they will not ripen properly. Don’t store Bartletts after 3 months or
Anjou longer than 6 months.
Maintaining desired temperatures for home storage of apples and pears
may be difficult. If you must settle for 40° F or even higher, you won’t
get the good results you would if you refrigerate at the optimum
temperatures. Sometimes cold storage facilities are available where you
may store your fruit for a set price per container.
Don’t mix windfalls (fruits that have dropped to the ground) with fruit
you pick from the tree. Windfalls are overripe and give off ethylene gas
which speeds ripening of picked fruit.
Desirable temperatures may be possible in refrigerator hydrator drawers
for small quantities.
An extra refrigerator can be used to store fruit, but do not take the
shelves out. When it is empty, for safety reasons take off the doors.
Home Storage Chart
Storage conditions
Where to store Temperature Humidity Storage
(F) period
_Vegetables:_
Beans and peas, Any cool, dry 32-40 Dry Many Years
dried place
Beets Storage cellar 32-40 Moist Fall-winter
or pit
Cabbage Storage cellar 32-35 Moist Fall-winter
or pit
Carrots Storage cellar 32-40 Moist Fall-winter
or pit
Celery Roots in soil 32-40 Moist Fall-winter
in storage
cellar
Onions Any cool, dry As near 32 Dry Fall-winter
place as possible
Parsnips Leave in 32-40 Moist Fall-winter
ground or put
in storage
cellar
Potatoes Storage cellar 45-48 Moist Fall-winter
or pit
Pumpkin, winter Unheated room 55-60 Dry Fall-winter
squash or basement
Rutabagas Storage cellar 32-40 Moist Fall-winter
or pit
Sweet Potatoes Unheated room 55-60 Dry Fall-winter
or basement
Tomatoes (green Unheated room 55-60 Dry 1-6 weeks
or white) or basement
Turnips Storage cellar 32-40 Moist Fall-winter
or pit
_Fruits:_
Most apples Fruit storage 30-32 Moist Fall-winter
cellar
McIntosh, Yellow Fruit storage 35-38 Moist Fall-winter
Newton & Rhode cellar
Island Greening
Grapes Fruit storage 31-32 Moist 4-6 weeks
cellar
Pears Fruit storage 30-31 Moist Fall-winter
cellar
Peaches Fruit storage 32 Moist 2 weeks
cellar
Apricots Fruit storage 32 Moist 2 weeks
cellar
Other Fruit
Storing fresh cherries, peaches, and apricots very long is difficult.
Refrigerate as close to 32° F as possible. Peaches ripen well at 65° to
85° and refrigerate well in hydrators for as long as 4 weeks. Peaches
may be stored in walk-in refrigerators in larger quantities.
Grapes are generally not adapted to long storage. Concord grapes may be
stored 4 to 6 weeks at 31° to 32° F. Catawba and Delaware varieties can
be held 8 weeks. Vinifera table grapes such as Emperor and Ribier will
keep 3 to 6 months at 30° to 31°.
Since apples, pears, grapes, and other fruit absorb odors from potatoes,
onions, and other vegetables, store them separately.
Some kitchen garden herbs, such as chives and parsley, may be potted and
cared for as house plants. These plants will supply flavoring and
garnishing to enhance wintertime meals.
Trying to predict exactly how long your fruits and vegetables can be
stored is next to impossible. Much depends on condition of the product
and how successful you are in maintaining correct temperatures and
humidity. Generally, you can keep parsnips and carrots all winter, late
potatoes 6 to 8 months, cabbage 3 months, onions 6 to 10 months, and
pumpkins, squash, root crops, and tomatoes 3 to 6 months.
_Cleanliness._ One last precaution: Keep the storage areas clean and
free of decaying fruit and vegetables; otherwise, molds and bacteria
will spread to your sound produce.
If you store nuts (especially peanuts), soybeans, other dry beans or
peas, make every effort to prevent growth of molds. Moisture,
temperature, and time are necessary to promote their growth. A harmful
toxin may be produced if mold growth is allowed to progress. It is
important that storage areas be regularly checked so as to avoid this
type of contamination.
Discard all produce that shows any sign of decay.
Insects, rats, and other pests can spread disease and are unwanted
guests in any food storage area. To escape these undesirables:
—Build them out. Close all cracks and use adequate screening over all
openings
—Prevent trash piles from accumulating
—Keep the storage area clean
—Control rats inside and outside. (Seek the advice of your county
Extension office or a sanitarian)
—Destroy any infested food
—Remove all containers at least once a year. Wash them and air dry in
the sun
—Remember that good housekeeping practices apply to all places where
food is stored
For Further Reading:
U.S. Department of Agriculture, _Storing Vegetables and Fruits in
Basements, Cellars, Outbuildings, and Pits_, H&G Bul. No. 119, on
sale by Superintendent of Documents, U.S. Government Printing
Office, Washington, D.C. 20402. 40¢.
Resurgence of Community Canneries
_by F. Aline Coffey and Roger Sternberg_[19]
A community cannery is a self-help facility equipped for preparing and
heat processing food. People bring in produce from their gardens and
through their own efforts preserve it for future use.
Community canneries began during the late 1800’s in response to the
desire of families to work together to preserve their food for the
off-season. At the end of World War II there were over 3,800 community
canneries in the United States. Most of these wartime canneries were
subsidized, but after the war the monies ceased. Growth of the food
industry, development of freezing techniques, and the lack of subsidy
led to a decline of the canneries.
Today there is a resurgence of interest in establishing community
canning centers. This has been influenced by the cost of food, a marked
increase in the concern for nutrition, and gardening activities.
A community cannery promotes the preservation of seasonal garden
surpluses for consumption during the nonproductive season. It encourages
small farmers and nonfarm individuals to produce more food, thereby
promoting self-sufficiency for families. It enables families who do not
own recommended food preservation equipment to use safe and reliable
equipment and techniques.
Availability of nonseasonal foods on a year-round basis can result in a
better diet for families, especially if the center incorporates
nutrition education classes as part of its program. People who grow
their own food may make substantial savings in their food budget. The
community cannery creates a social atmosphere of friendly, cooperative
work leading to tangible results, and promotes a feeling of
self-reliance.
Most of the community canneries in the country have been organized by
Community Action Agencies or similar community organizing groups.
Individuals, food co-ops, and other groups have successfully set up
canneries, but it is recommended that people wanting to establish a
canning center contact a community organizing agency. Normally, these
agencies have professional people who will work on such a project. They
have experience in writing proposals and are aware of potential funding
sources.
Support for the canning center can be enhanced by making a special
effort to include a diverse membership on a board of directors for the
center.
Farmers, low-income people, business people, contractors, Extension
personnel, community organizers, local officials, and members of the
clergy are all potential supporters and advisors for the cannery.
Although organizing a community cannery requires a lot of work, this
need not be a roadblock to initiating the project. It takes many hours
to plan the canning operation, draft proposals, develop community
support, locate a site, and to select, purchase and install equipment.
Because this can easily be a full-time job for one person, efforts
should be made to hire a coordinator. In many instances, paid community
organizers, Vista volunteers, and home economists have provided valuable
assistance in completing the work.
Preparation for and organization of the cannery are the foundation of
the project. At least six months should be set aside for organizing.
[Illustration: William E. Carnahan
Tomatoes in the canning process, at a community cannery.]
[Illustration: William E. Carnahan
Sweet corn ready to have kernels removed for canning.]
[Illustration: At later stage, liquid is poured over hot-packed
corn. Note one advantage of a community cannery is that quantities
of food can be processed in a few hours.]
Points to Consider
Here are some questions to consider before starting a community center:
How many people will commit themselves to organizing a center?
How much time will they give?
How much support can be expected from the community, town officials,
local growers?
How many community and family gardens are in the area?
How near are the community gardens to the cannery site?
Is the site near a well-travelled route?
Is parking available?
Can the canning center exist merely to provide a service to the
community, or will the cannery have to become involved in a commercial
venture?
If some food processed at the cannery is to be sold, are local farmers
willing to contract with the cannery to supply it with produce? How
close are these farmers to the cannery?
Is a building available for canning purposes (for example, some old
creamery)?
If so, what is the size of the building? What is its condition?
Are there cement floors and walls constructed so they can be washed down
daily?
Is there room for storage, a walk-in cooler?
Is the sewage system adequate?
Does the building have existing equipment that could be put to use?
Is a dependable supply of potable water available?
What is the minimum water pressure and is it constant?
Is the water “hard?” If so, what is the analysis?
What type of electricity is available?
What is the cost of electricity per KWH and demand rate for 240 volt, 3
phase, 60 cycle?
What is the availability and cost of gas (natural or LP) or of fuel oil?
What is the number of families expected to participate? How many are
low-income families?
What are the principal foods to be canned?
If it is anticipated that some products will be processed for sale, what
will those products be?
Is there a market for the “for-sale” items?
Will canning supplies such as jars, lids, screw bands, tin cans be
available? Can they be purchased at wholesale prices?
Is at least one person who is knowledgeable in food preservation methods
available to supervise the cannery?
What will be the charge for processing a pint or a quart of food?
Will low-income people be able to pay this amount?
Are funds available to subsidize the canning of food for low-income
people?
It is important to obtain a site easily accessible to the public.
Selectmen, property owners, realtors should be approached for potential
sites. Usually the center has limited funds, and it is difficult and
takes time to locate an appropriate building with low-cost rent.
In times of a strained economy and high cost of property maintenance,
the business community may be hesitant to provide low-cost housing for
the site.
Establishing the facility in a publicly owned building, such as a
school, is a solution in many communities. These canneries are a part of
the public school’s physical plant and have traditionally been operated
under supervision of the vocational agriculture and home economics
teachers, using school funds.
In recent years, some schools have wanted to close canneries for several
reasons: Lack of operating capital, limited use, lack of interest or
know-how on the part of participants and teachers. With the resurgence
of interest in canning, many new cannery ventures are located in schools
but are now funded separately from school budgets.
If the cannery is the result of a community endeavor, adjoining small
towns could appropriate funds sufficient to set up and man a center.
Such a proposal would have to be presented to the town governing bodies.
This points up the need for ample planning time. Devising means to allow
the cannery to remain open year-round would favor obtaining a site other
than in a public building.
Major Costs
Cost of organizing a community cannery is influenced by its size and
scope of operation. Expenses can be broken down into these major areas:
—Purchase and installation of equipment
—Building renovation
—Rent
—Labor
—Utilities
—Jars or cans
—Produce
—Miscellaneous costs (office supplies, freight, postage, insurance,
cleaning supplies, maintenance)
At least two companies manufacture community canning equipment (Ball
Corp. and Dixie Canner Equipment Co.). Prices start at $4,300 for a
single-unit operation, and go up to $20,000 for a large center. This
does not include the price of a steam boiler, which costs between $3,000
and $5,000. By fabricating some of its own equipment, and by buying used
equipment from canning and restaurant equipment suppliers, the cannery
can reduce some of its purchase costs substantially.
Installation of the canning equipment and the steam boiler needs to be
done by a licensed plumber or steam fitter, or be closely supervised by
such a person.
Renovation of a building and installation of the canning equipment can
cost between $4,000 and $8,000, including labor costs. Cost can be
reduced by soliciting volunteer labor from local craftsmen. The
organizers can handle much of the renovation, such as painting,
carpentry and cement work. Teams of vocational students may be willing
to take on the site renovations as part of their school training.
Salaries for employees can be paid from the cannery’s operating budget.
Labor costs can be reduced if the workers are already salaried employees
provided by other food-related agencies. The cannery can also be an
ideal training site for participants in the Comprehensive Employment and
Training Act (CETA) and can be staffed successfully in this way.
Regulations
Food and Drug Administration regulations regarding food processing do
not apply to community canning centers if they are not involved in
interstate commerce. In June, 1976, FDA issued “Suggested Minimum
Guidelines for Community Canning Operations” to protect the safety of
the consumer.
Environmental regulations that apply to the centers must be carefully
followed. Although these regulations are usually not hard to follow,
they often mean a possibly unplanned-for expense to the cannery. It may
be necessary to apply for a variance to zoning regulations. Cannery
supervisory boards should have a working knowledge of all requirements
of State and Federal agencies that regulate health, environment, fire,
safety, plumbing, electricity, and public building codes.
Sites for the centers should have sewage and draining systems that meet
demands of the centers. This would mean a septic system and leach
fields, or a municipal sewage system, the latter being the easiest and
least expensive method of disposal. Solid waste produced by the center
is termed “clean,” and effluent from the processing could be put through
a strainer, piped out of the center, and then deposited into a leach
field.
To maintain high standards of cleanliness and safety, at least one
supervisor should be on duty whenever the cannery is in operation. The
person in charge must have a thorough knowledge of every aspect of food
processing.
The Food and Drug Administration requires that a “certified registered
canner” be in attendance only when low-acid foods are processed to be
sold. An FDA-approved course is offered by the National Canners
Association for commercial cannery personnel in various sections of the
country. The cost would involve a registration fee of approximately $125
plus expenses. At present, the course content is geared chiefly toward
industry. A shift to a more practical approach would be of greater help
to community cannery personnel.
Cannery supervisors and attendants can participate in food preservation
classes and demonstrations provided by the Extension Service. When
canneries are equipped with commercial food preservation centers,
representatives of the manufacturing companies are available for
technical information to the cannery staff. Manufacturers may also
provide the cannery with a complete operations manual, processing
charts, and recipes.
Skills Needed
Cannery supervisors will benefit by employing people to work at the
cannery who can provide or learn such skills as:
_Bookkeeping/accounting_—to keep records of input and outflow of goods
and money; to pay bills.
_Management_—to oversee the flow of food through the center in an
efficient manner for smooth operation of the plant.
_Maintenance and repair_—to maintain equipment and housing in
operational condition.
_Purchasing/supply_—to ensure a supply of materials such as jars and
lids.
_Sales_—to manage sales of surplus retail products if these are
processed at the plant.
_Public relations_—to advertise and promote knowledge of canning
centers; to handle complaints and problems of patrons.
_Technical_—to provide detailed information on processing techniques,
food, nutrition, and gardening.
A form of recordkeeping on all foods processed at the plant is
essential. This kind of information would include such data as name of
person doing the processing, the date, specific food, number of jars,
method of processing, time in and time out, and an identification number
for foods processed for sale by the cannery.
Canning centers may be incorporated as independent nonprofit
cooperatives with a board of directors as the policymaking body. By
being organized in conformity with the traditional farmers’ cooperative
structure, the centers receive special tax considerations. Incorporation
on a nonprofit basis is a requirement of many funding sources. The
cooperative structure also lends itself to a tighter knit organization,
with members feeling they are part of the organization, responsible for
its affairs, and willing to pitch in and help if there is some work that
needs a few extra hands.
The community cannery should have general liability insurance to cover
injuries sustained by the workers or persons using the canning center.
Products liability insurance is unnecessary for the cannery operated
solely to provide a service to the community. For the cannery that sells
commercially, products liability insurance should be obtained.
[Illustration: Sealer in a community cannery.]
Hours, Fees
A community cannery should be available to all people interested in
preserving food. Ideally, canneries are open during daytime and evening
hours. Weekend hours are a possibility. When canneries are limited to
processing vegetables and fruits, at least 6 months of potential
operation are lost in certain sections of the country. If at all
possible, canneries should be operated to process a wider range of foods
such as jams, jellies, pickles, preserves, meat, fish, poultry.
[Illustration: William E. Carnahan
Tomato juice being processed at a community cannery. Since cannery
is operated by State of Virginia, only charge is for cans used.]
A processing fee is usually set for use of the canning equipment,
ranging from 5¢ to 10¢ for pints to 10¢ to 15¢ for quarts. These prices
do not include the cost of jar, lid, screw band, or any canning supplies
such as salt, vinegar, sugar, spices that may be sold at wholesale
prices at the cannery. An additional charge of 50¢ per hour is common
for the use of a pulper-juicer and steam-jacketed kettle.
It may be a financial hardship for some low-income families to meet
these costs, but they can be given the opportunity to exchange work time
at the cannery for payment. Families of limited resources might leave
off a percentage of their processed high-acid foods to be sold by the
cannery. Sponsoring agencies may apply for grants, such as might be
available from Title XX of the Social Security Act, in an effort to
subsidize canning costs for low-income families.
To date, no community canneries are completely economically
self-sufficient, so far as we know. There are centers in the South which
do enough community canning to pay for all their expenses except
salaries. To become self-supportive, some canneries are now developing
specialty products to be sold commercially. Organic-health food
distributorships and food co-ops are often a good market for community
cannery processed foods.
The future of community canneries depends on continued interest in home
gardening and food preservation, and concern for proper nutrition.
Undoubtedly, the cost of food in the marketplace will also be a
contributing factor.
Questions and Answers on Food Preservation
_by Carole Davis and Annetta Cook_[20]
Consumers frequently have questions regarding home food preservation
practices. Below are some questions commonly asked, and the answers.
They concern canning fruits, vegetables, pickles, and jellies, and
freezing fruits and vegetables.
_Why is open-kettle canning not recommended?_
In open-kettle canning, food is cooked in an ordinary kettle, then
packed into hot jars and sealed. The food is not processed after packing
in the jars.
Open-kettle canning is unsafe because temperatures reached are not high
enough to destroy all the spoilage organisms that may be in low-acid
foods, such as meat and vegetables, other than tomatoes.
Spoilage bacteria may also enter the food when it is transferred from
kettle to jar, making it undesirable as well to can other foods such as
fruits, pickles, preserves, and jams by this method.
_Why is oven canning unsafe?_
Jars may explode, causing personal injury or damage to the oven. Also,
temperatures obtained in the oven are not high enough to insure adequate
destruction of spoilage organisms in low-acid foods.
Times specified for boiling-water-bath processing of foods do not apply
to oven processing since the rate of heat penetration would be different
in the oven and the products could easily be underprocessed.
_Should jars and lids be sterilized before canning?_
No, not when the boiling-water-bath or pressure-canner method is used,
because the containers and lids are sterilized during processing. But be
sure jars and lids are clean.
_Why is no liquid added when tomatoes are canned?_
Because tomatoes provide their own juice if pressed gently when packed
raw, or when heated before packing hot into jars.
_Is it safe to add celery, green pepper, and onion to tomatoes when
canning them?_
No. Adding other vegetables lowers the acidity of tomatoes. Acidity
helps protect against the growth of botulinum bacteria, which can
produce a fatal toxin in canned foods. Specific recipes, times, and
temperatures determined scientifically for vegetable mixtures need to be
used for their safe canning.
_Why is headspace important in canning?_
Headspace—the distance between the surface of food and the underside of
the lid—allows for expansion of solids or bubbling up of liquid during
processing. If headspace is not adequate, some food in the container
will be forced out, leaving food particles or sirup on the sealing
surface and preventing a seal.
When too much headspace is allowed, some air may remain in the jar after
processing, causing food at the top of the jar to darken.
_What causes jars to break in a canner?_
Breakage can occur for several reasons: (1) Using commercial food jars
rather than jars manufactured for home canning, (2) Using jars that have
hairline cracks, (3) Putting jars directly on bottom of canner instead
of on a rack, (4) Putting hot food in cold jars, or (5) Putting jars of
raw or unheated food directly into boiling water in the canner, rather
than into hot water (sudden change in temperature—too wide a margin
between temperature of filled jars and water in canner before
processing).
_What causes liquid to be lost from jars during processing?_
Loss of liquid may be due to packing jars too full. Headspace must be
allowed between the top of the food and lid as specified in the
instructions for each food. Food expands when processed, so headspace
must be adequate or liquid will be forced out of the jar.
Liquid may be lost if the canner’s pressure fluctuates during
processing. Lowering the pressure too suddenly after processing may also
cause liquid to be lost. Pressure canner should be removed from the heat
and allowed to cool normally at room temperature.
_If liquid is lost from jars during processing, can more be added to
fill them again?_
No, because if the jar is opened and liquid added, this would allow
bacteria to enter the jar and you would need to process again.
Loss of liquid does not cause food to spoil, though food not covered by
the liquid may darken.
_Why does fruit sometimes float in the jar after canning?_
Fruit may float because it is packed too loosely, sirup is too heavy, or
because some air remains in tissues of the fruit after heating and
processing.
_How do you test the seal on home-canned foods?_
After jars have cooled, check two-piece lids by pressing the center of
the flat metal lid; if lid is down and will not move, jar is sealed.
For porcelain-lined caps, check seal by turning each jar partly over in
your hands. If no leakage occurs, the jar is sealed.
_What causes lids not to seal?_
If food has not been sufficiently heated, a vacuum may not be drawn on
the jar of food and the lid will fail to seal. Presence of food
particles or sirup on the jar rim could also prevent obtaining an
airtight seal. Each jar rim should be wiped clean of all food and sirup
before putting the sealing lid in place.
If food has been packed too tightly in the jars or if sufficient
headspace has not been allowed, expansion of the food during heating
could force sirup or food out of the jar, thus causing poor contact
between the lid and jar.
_Why should flat metal disks and rubber rings be used only once?_
Depressions in the rubber compound made when the lid or ring was first
used can prevent obtaining an airtight seal if used a second time.
_Why should metal bands be removed after jars have cooled?_
If bands are not removed soon after cooling, moisture between the ring
and jar may cause the ring to rust, thus making later removal of the
bands difficult. The band is no longer necessary after the jar has
cooled because the seal has been provided by the flat metal lid with
sealing compound and the vacuum created during cooling.
_What causes canned foods to change color?_
Darkening of food at the top of the jar may be caused by oxidation due
to air in the jar, or by too little heating or processing so that
enzymes are not destroyed. Overprocessing may cause discoloration of
foods throughout the jar.
Pink and blue colors sometimes seen in canned pears, apples, and peaches
are caused by chemical changes in the fruit coloring matter.
Iron and copper from cooking utensils or from water in some areas may
cause brown, black, and gray colors in some foods.
_Why do undersides of metal lids sometimes discolor?_
Natural compounds in some foods, particularly acids, corrode metal and
make a dark deposit on the underside of jar lids. This deposit on lids
of sealed, properly processed canned foods is harmless.
_Is it safe to use canned foods which have been frozen as the result of
storing them in an unheated storage area?_
Freezing does not cause the food to spoil unless the seal is damaged or
the jar broken. If the jar is no longer sealed, the food may still be
safe to eat if the jar is not broken and the food is still frozen and
has not been subjected to thawing and refreezing.
Remove the frozen canned food from jars as carefully as possible. The
food may need to thaw slightly to ease its removal from jars, but it
should be left in as large blocks as can be removed through the jar
opening.
Examine jars for breaks and hairline cracks. If any are found, discard
food from those jars. If no cracks are found, food may be transferred
from jars into freezer bags or containers and stored in the freezer, or
it may be kept in the refrigerator for use within a day or two.
Home-canned foods which have been frozen may be less palatable due to
texture changes than properly stored canned foods. Do not recan
home-canned foods which have been frozen.
_How do you protect canned foods against freezing?_
Wrap the jars in paper or cover them with blankets. However, if the
storage area temperature is expected to be below freezing (32° F) for
more than a day or two, move the food to a warmer storage area.
_What does mold on canned food indicate?_
It means the jar has not sealed and the food is spoiled. Even if mold
appears to be only on the surface, discard all food in the container
because parts of the mold may not be visible in the food.
_Is it safe to can foods without salt?_
Yes. Salt is used for flavor only in canned vegetables and is not
necessary for safe processing. Since the characteristic flavor and
texture of pickled vegetables depend on salt, do not omit this
ingredient from recipes for pickles and relishes.
_What kind of salt should be used in pickling? Why?_
Use pure granulated salt. Uniodized table salt can be used, but
materials added to the salt to prevent caking may make the brine cloudy.
Do not use iodized table salt because it may darken pickles.
_What type of vinegar should be used for making pickles? Can it be
diluted?_
Use cider or white distilled vinegar of 4% to 6% acidity (40 to 60
grain). Do not use vinegar of unknown acidity. Do not dilute vinegar
unless the recipe so specifies. If a less sour product is preferred, add
sugar rather than decrease vinegar.
_Why should pickles be processed in a boiling-water bath?_
Pickles require heat treatment to destroy organisms that cause spoilage,
and to inactivate enzymes that may affect flavor, color, and texture.
Heat processing in a boiling-water bath is recommended for all pickle
products. There is always danger of spoilage organisms entering the food
when it is transferred from kettle to jar. This is true even when the
utmost caution is observed and is the reason open-kettle canning is not
recommended.
_Why should plastic containers not be used when brining pickles?_
Vegetables being pickled undergo physical as well as chemical changes
during brining or fermentation. As a result of these changes, the
plastic may be affected, causing undesirable compounds to be formed or
leached from the plastic.
For fermenting or brining pickles, use a crock or stone jar, unchipped
enamel-lined pan, or large glass jar, bowl, or casserole.
_What causes pickles to be hollow?_
Hollowness in pickles generally results from poorly developed cucumbers,
holding cucumbers too long before pickling, too rapid fermentation, too
strong or too weak a brine during fermentation.
_What causes jelly to be too soft?_
Too much juice in the mixture, too little sugar, mixture not acid enough
(overripe fruit), or making too big a batch at one time.
_What makes jelly tough?_
Mixture was cooked too long to reach jellying stage because too little
sugar was used in proportion to the pectin and acid in the juice.
_What makes crystals form in jelly?_
Crystals throughout the jelly may be caused by too much sugar in the
jelly mixture, or cooking the mixture too little, too slowly, or too
long. Crystals on top of jelly that has been opened and allowed to stand
are due to evaporation of liquid.
Tartrate crystals in grape jelly may occur if juice has not been allowed
to stand overnight and then strained through a double thickness of
cheesecloth before preparing jelly.
_Is a one-door refrigerator-freezer combination suitable for freezing
and storage of frozen fruits and vegetables?_
It may be difficult to obtain the recommended temperature of 0° F or
below for freezing and storing foods in this style freezer without
freezing food in the refrigerator part as well.
Recommended storage times are severely reduced if a freezer does not
maintain 0° F or below. If freezer temperatures are above 10°, do not
store frozen food for more than several weeks.
_Can containers for commercial foods, such as cottage cheese, margarine,
milk, yogurt, ice cream, or sour cream, be used for freezing fruits and
vegetables?_
Waxed cardboard cartons which previously contained dairy products are
not sufficiently moisture-vapor-resistant to use for packaging foods to
be frozen.
Plastic commercial-food containers are suitable if they can be tightly
sealed and do not become brittle and crack at low temperatures, thus
exposing the food to the air.
_Can citric acid or lemon juice be used to help prevent fruit from
turning dark during freezer storage?_
Although these products can be used as anti-darkening agents, neither is
as effective as ascorbic acid. Often the quantity of citric acid or
lemon juice needed to prevent darkening is so large that natural flavors
are masked or the fruit becomes too sour.
_Why is it necessary to wash and blanch vegetables before they are
frozen?_
Washing removes dirt and some of the bacteria from vegetables. Freezing
inhibits the growth of bacteria, but does not kill them. Thus it’s
important that the food, as well as all surfaces it touches, be kept
clean so that the number of bacteria on the food is held to a minimum.
Bacteria can grow on food if the temperature rises during freezer
storage, and when food is thawed.
Except for green peppers and mature onions, vegetables must be blanched
to destroy enzymes which could cause undesirable changes in flavor,
texture, and color during freezer storage.
_Why can green peppers and mature onions be frozen without blanching?_
Unlike other vegetables, green peppers and onions do not lose quality
during freezer storage if their enzymes are not destroyed by blanching
before freezing.
Green peppers frozen without heating are better suited for use in
uncooked foods than are blanched peppers. Some of the characteristic
flavor of onions is lost if this vegetable is blanched before freezing.
_Why is corn which is frozen on-the-cob blanched for longer times than
cut corn?_
Longer blanching of corn frozen on-the-cob is necessary so that enzymes
present in the cob will be destroyed. Otherwise, enzymes in the unheated
cob can cause undesirable flavor changes in the corn kernels.
Corn frozen off-the-cob needs only to be blanched just enough to destroy
enzymes in the kernels.
_Can vegetables be blanched by steaming instead of by heating in boiling
water?_
The following vegetables may be heated in steam: broccoli, mushrooms,
pumpkin, winter squash, and sweet-potatoes.
To steam these vegetables, put 1 to 2 inches of water in a large kettle;
bring water to a boil. Add a basket containing a single layer of
prepared vegetable; keep the basket at least 1 inch above the water.
Cover kettle and start timing.
Steam broccoli 3 minutes; sliced mushrooms, 3 minutes; whole mushrooms
(less than 1-inch diameter), 5 minutes. Steam pumpkin, winter squash, or
sweet-potatoes until tender.
_Is it necessary to make an adjustment in blanching times for vegetables
at altitudes above sea level?_
At altitudes 5,000 feet or more above sea level, heat vegetables 1
minute longer than the time given in directions for the vegetable being
blanched.
_What can be done to prevent food from thawing if the freezer should
stop running?_
Never open the freezer unnecessarily. A fully-loaded freezer will
usually remain cold enough to keep food frozen for 2 days if the door is
not opened; a half-loaded freezer may not stay cold enough more than a
day.
If power cannot be restored or the freezer cannot be fixed before the
food would start to thaw, use dry ice. If dry ice is obtained shortly
after the failure has occurred and the freezer is fully loaded, 25
pounds of dry ice should keep a 10-cubic-foot freezer at temperatures
below freezing for 3 to 4 days; if freezer is less than half-full, for 2
to 3 days.
Place dry ice on boards or heavy cardboard on top of the packages of
food. Handle dry ice carefully—never with your bare hands. Wear gloves
to prevent burns.
Another alternative is to move food to a neighbor’s freezer or to a
freezer locker plant where space can be rented.
_Can vegetables and fruits which have thawed be refrozen?_
Frozen foods that have thawed may be safely refrozen if they still
contain ice crystals or if they are still cold—about 40° F—and have been
held no longer than 1 or 2 days at refrigerator temperatures (32° to
40°) after thawing.
Since thawing and refreezing reduces the quality of fruits and
vegetables, use refrozen foods as soon as possible to save as much of
their eating quality as you can.
Food Preservation Glossary
_compiled by Annetta Cook and Carole Davis_[21]
Acid food—Food with a pH of 4.6 or below. An acid food can be safely
processed in a boiling-water bath for specified times. Includes
most fruits, tomatoes, and pickled vegetables.
Anaerobes—Bacteria capable of growing without air, as in a sealed
container of canned food.
Blanching—Heating vegetables by immersion in boiling water, steaming,
sauteing, or stewing to inactivate enzymes capable of causing
quality changes in foods during freezer storage.
Boiling-water-bath Canner—A large kettle with lid, rack, and cover; must
be deep enough to allow jars to be covered with 1 to 2 inches of
water and still have additional height for water to boil actively.
Suitable for processing acid foods.
Botulism—Food-borne illness caused from eating canned foods containing
the toxin produced by _Clostridium botulinum_, an anaerobic
bacterium. This organism can grow and produce toxin in sealed jars
of canned foods that are improperly processed.
Canning—Preserving food in airtight rigid containers. Micro-organisms
are destroyed by heat-processing containers of food at the
temperature and time specified for each food. It is essential to
follow reliable canning instructions exactly to insure a safe
canned product that is free from botulism-causing bacteria and
spoilage organisms.
Cold Pack—Raw, unheated food packed into canning containers and covered
with boiling sirup, juice, or water.
Dehydrator—A device which removes moisture, a dryer.
Enzymes—Proteins involved in plant growth processes including maturation
and ripening. Enzymes can cause loss of quality in food if they
remain active during storage. They are destroyed by canning, or by
blanching vegetables before freezing.
Freezer Burn—Small, white, dehydrated areas which occur on improperly
wrapped frozen foods. This condition is harmless, but if extensive
can cause food to become tough or lose flavor.
Freezing—Preserving food by storing at low temperatures. The recommended
temperature for freezer storage is 0° F or below.
Headspace—The space between the top of food in a container and the
container lid or closure.
Hot Pack—Food heated in sirup, water or steam, or juice, and packed hot
into canning jars.
Hydrator (Vegetable Crisper)—A drawer-like section in refrigerators
which protects fresh fruits and vegetables from drying out during
refrigerator storage.
Low-acid Food—Food with pH above 4.6. A low-acid food requires
processing at high temperature under pressure to destroy
micro-organisms and insure a safe canned product. Includes all
vegetables except tomatoes.
Micro-organism—Includes bacteria, molds, and yeasts, which when present
in food can cause spoilage and even food poisoning. Therefore,
they must be destroyed in canning foods or their growth prevented
in freezing and drying foods.
Moisture-vapor-proof—Packing materials that prevent loss of moisture
from foods during freezer storage. Examples include glass, rigid
plastic, and metal freezer containers.
Moisture-vapor-resistant—Packing materials that protect foods from
moisture loss during freezer storage. Examples include freezer
wraps—paper, plastic, or foil—plastic bags, waxed freezer cartons.
Molds—Microscopic fungi which form air-borne spores (seeds) that may
alight on food and grow into cottony mats or fuzz. Some molds or
their end products may be harmful, and moldy vegetables or fruit
should not be canned. Molds are destroyed by proper canning, but
they may develop in leaky containers. Food from leaky containers
or any canned food showing mold growth should be discarded without
tasting.
Open-kettle Canning—Procedure whereby food is cooked in an ordinary
kettle, then packed into hot jars and sealed. Jars of food receive
no additional heat processing. This is a dangerous practice as
spoilage organisms may enter the jar during the transfer of food
from kettle to jar. In low-acid foods, temperatures obtained are
not hot enough to insure destruction of all spoilage organisms
that may be present in the food.
Pack—Designates how food is packed into containers. Specifies the
temperature of food when packed into jars for canning, or the
method of sweetening fruits for freezer packs.
Pectin—A substance occurring naturally in many fruits which causes the
juice to thicken or gel after heating if the proper proportions of
sugar and acid are present. Natural pectins are more prevalent in
underripe fruit than mature or overripe fruit. Some fruits have
enough natural pectins to make high quality jams and jellies.
Others require addition of commercial pectins which are made from
either citrus peel or apples.
pH—Measure of acidity of a product. The lower the pH the higher the
acidity.
Preserve—To maintain the quality of food for consumption at a later
time. Accomplished by canning, freezing, pickling, drying, or
making jelly, jams, or preserves.
Processing—Heating food in closed canning jars to insure destruction of
micro-organisms so the canned food will remain unspoiled and safe
to eat. Acid foods—such as fruits, tomatoes, and pickles—and jams
and preserves are safely processed in a boiling-water-bath.
Low-acid vegetables (all vegetables except tomatoes) require
processing at higher temperature by use of a pressure canner or
pressure saucepan. Times required to insure an adequate process
are specified in canning directions for each food.
Sirup Pack—Fruit is packed for freezing in a sugar sirup made by
dissolving sugar in water.
Steam-pressure Canner—A large, heavy metal pan having a tight-fitting
cover which is fitted with safety valve, steam vent or petcock,
and a gage—either weighted or dial. Used for processing low-acid
foods under pressure at high temperatures in order to insure their
safety.
Steam-pressure Saucepan—Smaller than a canner. If equipped with a gage
to maintain pressure at 10 pounds, it is suitable for processing
food in pint jars.
Sugar Pack—Sugar is added directly to fruit and mixed gently to draw
juice from fruit before packing into freezer containers.
Unsweetened Pack—Fruit packed for freezing without any sweetening added.
It may be packed dry or covered with water.
Footnotes
[1]Edmund A. Zottola is Extension Food Microbiologist and Isabel D. Wolf
is Extension Specialist, Foods and Nutrition, at the University of
Minnesota, St. Paul.
[2]Gerald D. Kuhn is Professor, Food Science Extension, and Louise W.
Hamilton is Professor, Foods & Nutrition Extension, The Pennsylvania
State University, University Park.
[3]Ruth N. Klippstein is Professor, Division of Nutritional Sciences,
Cornell University, Ithaca, N.Y.
[4]Frances Reasonover is Extension Food and Nutrition Specialist, Texas
A & M University, College Station.
[5]Charlotte M. Dunn is Food and Nutrition Specialist, University of
Wisconsin-Extension, Madison.
[6]Nadine Fortna Tope is Extension Specialist in Food Conservation and
Preparation, North Carolina State University, Raleigh.
[7]Carole Davis is a Supervisory Food Technologist, Consumer and Food
Economics Institute, Agricultural Research Service.
[8]These instructions are for green beans only. Procedures and
processing times are specific for each vegetable. See USDA Home and
Garden Bulletin No. 8, _Home Canning of Fruits and Vegetables_, for
directions for canning other vegetables.
[9]These instructions are for peaches only. Procedures and processing
times are specific for each fruit. See USDA Home and Garden Bulletin
No. 8, _Home Canning of Fruits and Vegetables_, for directions for
canning other fruits.
[10]Annetta Cook is a Food Technologist in the Consumer and Food
Economics Institute, Agricultural Research Service.
[11]These instructions are for strawberries only.
[12]These instructions are for green peas only. Preparation procedures
and blanching times are specific for each vegetable. See USDA Home
and Garden Bulletin 10, _Home Freezing of Fruits and Vegetables_,
for directions for freezing other vegetables.
[13]Catherine C. Sigman is Extension Home Economist—Foods, University of
Georgia, Athens. Kirby Hayes is Professor, Department of Food
Science and Nutrition, University of Massachusetts, Amherst.
[14]Isabelle Downey is Home Economist-Food Preservation, Cooperative
Extension Service, Auburn University, Auburn, Ala.
[15]Philip Wagner is Proprietor, Boordy Vineyards, Riderwood, Md., and
author of _Grapes Into Wine_. J. R. McGrew is with the Agricultural
Research Service, Beltsville, Md.
[16]Dale E. Kirk is a Professor and Agricultural Engineer at Oregon
State University, Corvallis. Carolyn A. Raab is Extension Foods and
Nutrition Specialist at Oregon State.
[17]Ralph W. Johnston is Chief, Microbiology Staff, Meat and Poultry
Inspection Program, Food Safety and Quality Service.
[18]Anton S. Horn is Extension Horticulturist, University of Idaho,
Boise. Esther H. Wilson is Extension Nutrition Specialist,
University of Idaho, Moscow.
[19]F. Aline Coffey is Foods and Nutrition Specialist, Vermont Extension
Service, University of Vermont, Burlington. Roger Sternberg is
Project Coordinator, Bread and Law Taskforce, Montpelier, Vt.
[20]Carole Davis and Annetta Cook are Food Technologists with the
Consumer and Food Economics Institute, Agricultural Research
Service.
[21]Annetta Cook and Carole Davis are Food Technologists with the
Consumer and Food Economics Institute, Agricultural Research
Service.
U.S. GOVERNMENT PRINTING OFFICE: 1978 O-278-050
Transcriber’s Notes
—Silently corrected a few typos.
—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
—In the text versions only, text in italics is delimited by
_underscores_.
—Transcribed or tabulated some text within illustrations.
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