Berries and all ripe, mellow fruit require but little cooking, only
long enough for the sugar to penetrate. Strew sugar over them, allow
them to stand a few hours, then merely scald with the sugar; half to
three-quarters of a pound is considered sufficient. Harder fruits like
pears, quinces, etc., require longer boiling. The great secret of
canning is to make the fruit or vegetable perfectly air-tight. It must
be put up boiling hot and the vessel filled to the brim.
Have your jars conveniently placed near your boiling fruit, in a tin
pan of hot water on the stove, roll them in the hot water, then fill
immediately with the hot, scalding fruit, fill to the top, and seal
quickly with the tops, which should also be heated; occasionally screw
down the tops tighter, as the fruit shrinks as it cools, and the glass
contracts and allows the air to enter the cans. They must be perfectly
air-tight. The jars to be kept in a dark, cool, dry place.
Use glass jars for fruit always, and the fruit should be cooked in a
porcelain or granite-iron kettle. If you are obliged to use common
large-mouthed bottles with corks, steam the corks and pare them to a
close fit, driving them in with a mallet. Use the following wax for
sealing: One pound of resin, three ounces of beeswax, one and one-half
ounces of tallow. Use a brush in covering the corks and as they cool,
dip the mouth into the melted wax. Place in a basin of cold water.
Pack in a cool, dark and dry cellar. After one week, examine for
flaws, cracks or signs of ferment.
The rubber rings used to assist in keeping the air from the fruit cans
sometimes become so dry and brittle as to be almost useless. They can
be restored to normal condition usually by letting them lie in water
in which you have put a little ammonia. Mix in this proportion: One
part of ammonia and two parts water. Sometimes they do not need to lie
in this more than five minutes, but frequently a half hour is needed
to restore their elasticity.