Pacific Northwest PNW 421 Using Manual - page 9
designed to be used on a flat top (glass or ceramic)
range because they have concave bottoms. On a flat
top range, a large area of the bottom will be out of con-
tact with the heat source, preventing the transfer of heat
and the buildup of pressure.
Steps for successful pressure canning
1. Put 2 to 3 inches of hot water in the canner (fig.2).
When canning fish or other foods with a long pro-
cessing time, add additional water to be certain the
canner does not boil dry. Place filled jars on the rack,
using a jar lifter. Fasten canner lid securely.
2. Leave the weight off the vent port or open the pet-
cock. Heat on high heat until steam flows from the
petcock or vent port.
3. Maintaining high heat, exhaust steam for 10 minutes
and then place the weight on the vent port or close
the petcock. The canner will pressurize in the next 3
to 5 minutes.
4. Start timing the canning process when the dial gauge
indicates the recommended pressure or when the
weighted gauge begins to jiggle or rock.
5. Regulate the heat under the canner to maintain a
steady pressure at or slightly above the correct gauge
pressure. The correct gauge pressure must be main-
tained for the entire processing time. If the pressure
drops below the target pressure, reset your timer and
process for the entire recommended processing time.
Quick and large pressure variations during process-
ing may cause jars to lose liquid. Generally, weighted
gauges on Mirro canners should jiggle about two or
three times per minute. On Presto canners, the
weighted gauge should rock slowly throughout the
process. Always read the manufacturer's instruction
sheet for how to check for proper pressure.
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