Use jars made especially for home canning so the jars will be the right
size for the processing time and temperature used, properly heat
tempered, and resistant to mechanical shock. Always check jars before
using to be sure they do not have nicks or cracks. Wash jars in hot,
soapy water and rinse well.
It is important to use standard jar closures. They are designed to fit
home canning jars correctly, and are made from suitable materials to
provide a proper seal. One of the most popular types is the two-piece
lid with a metal ring or band and a flat metal disk with a sealing
compound. Flat metal disks can be used only once since they may not seal
properly if reused. Metal bands may be used repeatedly if they are not
rusted or dented.
[Illustration: Screw ring band and disk.]
Wash and rinse lids and bands. Metal lids with sealing compound may need
boiling or holding in boiling water for a few minutes; follow the
manufacturer's directions. Porcelain-lined zinc caps with rubber
shoulder rings can also be used to seal jars. Rubber rings should be
used only once.
Water-bath canners are readily available on the market. However, any
large metal container may be used for a water-bath canner if it is deep
enough so the water is well over the tops of the jars and has space to
boil freely. Allow 2 to 4 inches above jar tops for brisk boiling. The
container or canner must have a tight fitting cover and a rack to allow
water to circulate under the jars.
The steam-pressure canner is made of heavy metal and has a cover which
fastens to make the pan steam-tight. The cover is fitted with a safety
valve, a petcock or vent, and a gage--either weighted or dial. All parts
of the canner must be clean and in good working order. Check the gage
before the canning season, and also during the season if canner is used
often. The weighted ones need only be checked to determine if they are
thoroughly clean. A dial gage can be tested for accuracy by a county
Extension agent or an equipment manufacturer.
A pressure saucepan may be used for canning pint jars of food. However,
20 minutes must be added to the processing time recommended for a
particular food canned with the pressure canner. This is because
pressure saucepans heat and cool more rapidly than pressure canners do.
Thus additional time is needed to compensate for the otherwise reduced
exposure of the food to heat.