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 degrees F.
As a beginning 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.
The following are some common low-acid vegetables: asparagus, beans
(snap or shelled), beets, carrots, corn, potatoes, pumpkin, squash,
and sweet potatoes.
Apples, apricots, berries, cherries, grapefruit, peaches, pineapple,
rhubarb, and tomatoes are examples of high-acid fruits and vegetables.
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 degrees 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 degrees F.
Yeasts, mold and non-spore forming bacteria are readily controlled
by processing at 212 degrees 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.
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 "lightening"
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 styles 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 degrees 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 one-half 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.
This pressure is adjusted for high altitude. For information on
high altitude canning, check with your county extension office.
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
the 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 syrup 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 syrup that could prevent sealing. But even when using a
funnel you still need to wipe the jar rim.
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 one quarter 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.
WET 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 in the canner.
Place raw-pack jars in water that is hot (180 to 190 degrees 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 mitts, 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 degrees
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" color, 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.
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.
Destroy food if any of these signs are obvious; discard out of reach
of humans and animals.
All low-acid, home-canned food should be boiled 10 to 20 minutes
to ensure 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.
HOME CANNING OF FRUITS AND VEGETABLES
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 degrees F or, when under 10 pounds of pressure, at 240 degrees.
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. For every 1,000 feet in altitude, increase processing
time by one minute if the recommended time is 20 minutes or less.
If the recommended time is more than 20 minutes, increase processing
time by two minutes per 1,000 feet of altitude.
At altitudes above sea level it takes more than 10 pounds of pressure
for the temperature of boiling water to reach 240 degrees 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
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. Fat 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.
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 rinds 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 syrup, juice, or water.
When foods are hot packed they are heated in syrup, 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 syrup,
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 under processing.
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 1/4 inch.
When the jar is removed from the canner, tighten the cap to complete
the seal.
Processing Fruits
Sugar or sugar-water syrup 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 syrup--mix sugar with water or juice extracted from
the fruit. Proportions for 3 types of syrup are as follows:
Thin syrup: 2 C sugar to 4 C liquid
Medium syrup: 3 C sugar
to 4 C liquid
Heavy syrup: 4 3/4 C
sugar to 4 C liquid
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.
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 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.
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.
