Pacific Northwest PNW 421 Using Manual - Using and
using and
caring for your
pressure canner
Pressure canning is the only recommended method for
canning meat, poultry, seafood, and vegetables. Using
boiling water canners for these low-acid foods poses a
real risk of botulism poisoning.
Botulism is caused by a toxin produced by bacteria
called
Clostridium botulinum. These bacteria are very
hard to destroy at boiling-water temperatures (212°F at
sea level). But at the higher temperatures of a pressure
canner, they are easier to destroy. Home pressure can-
ning recommendations are based on processing food at
240°F. All low-acid food should be processed at this
temperature.
At sea level, a weighted gauge canner operated at 10
pounds pressure per square inch provides an internal
temperature of 240°F. A dial gauge canner operated at
sea level, however, must be operated at 10.5 pounds
pressure to reach 240°F. We recommend operating dial
gauge canners at 11 pounds pressure at sea level
because it is easier to monitor this pressure on the
gauge. Higher pressures are needed to attain 240°F at
altitudes above sea level.
At a temperature of 240°F, the time needed to destroy
bacteria in low-acid canned food ranges from 20 to 110
minutes. The exact time depends on the kind of food,
the way it is packed into jars, and jar size. The exact
times provided in recipes for specific foods have been
determined by laboratory research. Be sure to use
them!
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