enough,
carefully and thoroughly enough, to convince themselves and others
that the cold-pack method and the intermittent method, which methods
are employed for cooking the product in the jar, are sure, safe,
reliable and efficient methods. So if your food spoils convince
yourself it is not the method but something else. Spoilage is due to
imperfect jars, imperfect rubbers, imperfect sealing of tin cans,
careless blanching, insufficient cold dipping or poor sterilizing.

CAN-RUBBERS

Possibly your canning troubles are all due to using a poor grade of
rubber rings. This is poor economy. Rubbers are apt to give more
trouble than anything else to canners when using glass jars. Many of
the rubbers sold are of a very poor quality, disintegrating quickly
when subjected to heat and strain. My sister, canning in the hot
climate of India, has more trouble with the rubber proposition than
anything else.

You want good rubbers, are willing to pay for them, and here is what
you should know about rubber rings.

The one-period, cold-pack method and the intermittent method of home
canning require a rubber ring essentially different from that commonly
used in the old hot-pack method of home canning. Investigation shows
that many of the rings upon the market are unsuitable for these newer
methods, being unable to withstand the long periods of boiling
required in the canning of vegetables and meats.

Practical canning tests have indicated that rubber rings for use in
this method should meet the following requirements:

Inside Diameter. The ring should fit closely, requiring a little
stretching to get it around the neck of the jar. For standard jars the
ring should have an inside diameter of 21/4 inches.

Width of Ring and Flange. The width of the ring or flange may vary
from one-fourth of an inch to twelve thirty-seconds of an inch. Tests
which have been made show that fewer cases of "blow-out" occur when
the flange is ten thirty-seconds of an inch.

Thickness. Rubber rings as found on the market may vary from 1/18 to
1/10 of an inch in thickness. Tests show that 1/12 of an inch in
thickness is sufficient to take up the unevenness in the jar and still
not so thick as to make it difficult to place the cap or adjust the
bail.

Cold-pack and intermittent-canning require a rubber ring that is
tough, does not enlarge perceptibly when heated in water or steam, and
is not forced out of position between the top and the jar by slig