Michigan State University Extension
Preserving Food Safely - 01600949
10/13/97

### USING PRESSURE CANNERS

        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 is completed, turn off the

            heat, remove the canner from heat if possible, and

            let the canner depressurize.  DO NOT FORCE-COOL

            THE CANNER.  If you cool it with cold running

            water in a sink, or open the vent port before the

            canner depressurizes by itself, liquid will spurt

            from jars, causing low liquid levels and jar 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 vent port or petcock has been open for 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.

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