Follow these steps for successful pressure canning:
1. Put 2 to 3 inches of hot water in the canner. Place
filled jars on the rack, using a jar lifter. Fasten
canner lid securely.
2. Leave weight off vent port or open petcock. Heat at
the highest setting until steam flows from the petcock
or vent port.
3. Maintain high heat setting, exhaust steam 10
minutes, and then place weight on vent port or close
petcock. The canner will pressurize during the next 3
to 5 minutes.
4. Start timing the process when the pressure reading
on the dial gauge indicates that the recommended
pressure has been reached, or when the weighted gauge
begins to jiggle or rock.
5. Regulate heat under the canner to maintain a steady
pressure at or slightly above the correct gauge
pressure. Quick and large pressure variations during
processing may cause unnecessary liquid losses from
jars. Weighted gauges on Mirro canners should jiggle
about 2 or 3 times per minute. On Presto canners, they
should rock slowly throughout the process.
6. When the timed process completed, turn off the
heat, remove the canner from heat if possible, and let
the canner depressurize. Do not force-cool the canner.
Forced cooling may result in food spoilage.
Cooling the canner with cold running water or opening
the vent port before the canner is fully depressurized
will cause loss of liquid from jars and seal failures.
Force-cooling may also warp the canner lid of older
model canners, causing steam leaks. Depressurization
of older models should be timed. Standard-size
heavy-walled canners require about 30 minutes when
loaded with pints and 45 minutes with quarts. Newer
thin-walled canners cool more rapidly and are equipped
with vent locks. These canners are depressurized when
their vent lock piston drops to a normal position.
7. After the canner is depressurized, remove the weight
from the vent port or open the petcock. Wait 2
minutes, unfasten the lid, and remove it carefully.
Lift the lid away from you so that the steam does not
burn your face.
8. Remove jars with a lifter, and place on towel or
cooling rack, if desired.
* USDA Agriculture Information Bulletin No. 539 (rev. 1994)
* Meal-Master format courtesy of Karen Mintzias
