Pacific Northwest PNW 421 Using Manual - Safety Features
are therefore essential when a gauge reads higher than
it should. Gauges may be checked at many county
extension offices; contact the pressure canner manufac-
turer for other options.
Safety features
The vent port (steam vent) lets air out of the canner and
releases steam as needed. On weighted-gauge pressure
canners the weight on the vent controls the escape of air
or steam. Generally, dial-gauge pressure canners have a
petcock attached to the vent. A petcock releases steam
and air when open and holds the steam when closed.
The safety fuse, safety plug, safety release plug, or
overpressure plug is an important safety feature of
pressure canners. These are thin metal inserts or rubber
plugs designed to release pressure from the canner if
the temperature or the pressure becomes dangerously
high. Metal alloy plugs melt when the pressure gets too
high or the canner boils dry. Composition-type plugs are
blown out by excessive pressure. Both can be easily
and inexpensively replaced. Do not pick at or scratch
plugs when cleaning lids.
The metal rack is another safety feature of the pressure
canner. The rack keeps jars off the bottom of the canner
and prevents jar breakage.
The Underwriters' Laboratories (UL) seal means that
your pressure canner has passed certain standardized
tests for fire, electric shock, and related causes of acci-
dental injury. When buying a new pressure canner,
check for the Underwriters' Laboratories seal.
Caring for your pressure canner
The canner
Before each use, wash the canner with hot, soapy water
then rinse and dry it. Do not use strong alkalis such as
sodium hydroxide or lye, scouring powder, or baking
soda because they darken and stain aluminum.
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