Pressure Canning; How To Pressure Can Foods - Presto Pressure Canner and Cooker Instructions And Recipes Manual

UNLOCKED
Fig. K
Air Vent/Cover Lock
in DOWN Position.
No Pressure in Unit.
If the cover is not rotated sufficiently (cover handles di-
rectly above body handles), the air vent/cover lock will
only raise slightly and steam will continue to flow from
it, preventing pressure from building.
 (During canning, it is necessary to exhaust air from the
canner before placing the pressure regulator on the vent
pipe. See page 5, step 7.) The pressure regulator is placed
on the vent pipe as soon as the cover is closed securely
when cooking. During canning or cooking, moisture may
appear near the pressure regulator, overpressure plug and
air vent/cover lock. This is normally due to condensation.
This does not affect operation of the canner.
To reduce pressure at the end of the canning or cooking
period, turn heat off and/or remove the canner from the
burner. Cool according to instructions in recipe. Pressure
is completely reduced when the air vent/cover lock has
dropped and no steam escapes when the pressure regula-
tor is tilted. Do not remove the pressure regulator until
pressure is completely reduced. Always remove the
pressure regulator before opening canner.
If the air vent/cover lock remains in its raised position,
there may still be pressure in the canner. Do not remove
the pressure regulator until the air vent/cover lock drops
and no steam escapes when the pressure regulator is tilted.
The cover should not be forced open. You may tap the
air vent/cover lock lightly with a spoon. If pressure is
present, steam will escape and the air vent/cover lock
will pop back up. Continue to cool the canner until the
air vent/cover lock drops.
HELPFUL HINT: To help yourself understand the op-
eration of the pressure canner and cooker, pour 4 cups of
water into the canner and follow the step-by-step instruc-
tions beginning with step 5 on page 5. For actual usage
of the canner/cooker, follow the complete instructions
beginning at the bottom of next column for pressure
canning and on page 15 for pressure cooking.

Pressure Canning

The United States Department of Agriculture, Washington,
D.C. recommends the Pressure Canner as being the only safe
method for canning low-acid foods—vegetables, meats, and
poultry.
There are invisible microrganisms present all around us.
Fruits, vegetables, and meat contain these microrganisms
naturally, and yet, they are not a problem unless food is left
to sit for extended periods of time, causing food spoilage.
This is nature's way of telling us when food is no longer fit
to eat.
There are four basic agents of food spoilage—enzymes,
mold, yeast, and bacteria. Canning interrupts the natural
spoilage cycle so food can be preserved safely. Molds, yeast,
LOCKED
and enzymes are destroyed at temperatures below 212˚F, the
temperature at which water boils (except in mountainous
regions). Therefore, boiling water processing is sufficient to
destroy those agents.
Air Vent/Cover
Lock in UP Position.
Pressure in Unit.
Bacteria, however are not as easily destroyed. The bacteria,
Clostridium botulinum produces a spore that makes a poison-
ous toxin which causes botulism. This spore is not destroyed
at 212˚F. In addition, the bacteria thrive on low-acids in the
absence of air. For a safe food product, low-acid foods need
to be processed at 240˚ or higher, temperatures only achieved
with a pressure canner.
In pressure canning, some of the water in the pressure canner
is converted to steam, which creates pressure within the can-
ner. As pressure increases, temperature increases, 5 pounds
pressure—228˚F, 10 pounds pressure—240˚F, 15 pounds pres-
sure—250˚F. This pressurized heat destroys the potentially
harmful bacterial spores. As the jars cool, a vacuum is formed,
sealing the food within and preventing any new microorgan-
isms from entering and spoiling the food.
As a safeguard against using canned foods which may be
affected with spoilage that is not readily detected, pour all
low-acid foods (meats and vegetables) into a saucepan and
boil 10 to 15 minutes before tasting or using.
Many times odors that cannot be detected in the cold product
will become evident by these methods. If, after boiling, food
does not smell or look right, discard it without tasting.
MASON JARS: While there are many styles and shapes of
glass jars on the market, only Mason jars are recommended
for home canning. Mason jars are available in
quart capacities with threads on which a cap may be screwed.
See the chart below for the jar capacity of your canner. Ad-
ditional information may be obtained from the manufacturers
of Mason Jars.
CLOSURES FOR MASON JARS: The two-piece metal cap
consists of a flat metal lid held in place with a screw band.
A rubber compound on the underside of the lid forms a seal
during processing. Follow the closure manufacturer's direc-
tions for using the two-piece cap and for testing for a proper
seal. If the closure has not sealed, completely reprocess or
use the food immediately. Refer to the closure manufacturer's
directions for additional information.
Please note: To double deck pint and half pint jars, see page 13.

How to Pressure Can Foods

IMPORTANT: Read carefully. Do not attempt to use your
canner before reading these instructions.
Follow these step-by-step instructions for pressure canning
in your canner. Prepare food according to the directions in
4
CANNER JAR CAPACITIES
MODEL NO.
beginning with ⁄ PINT
1
2
0175 24
0178 24
⁄ pint, pint, and
1
2
(MAXIMUM CAPACITY)
1 PINT 1 QUART
up to 10 7
up to 20 7