51. The OVEN METHOD oven method of canning is thought to be very
satisfactory by many housewives, but, as it is necessary to remove the
covers after cooking the contents of the jars, food canned in this way
is subjected to contamination, just as in the open-kettle method. In
addition, the jars are difficult to handle in the oven, owing to the
extreme heat that is required to cook the food in the jars.
52. In canning by the oven method, proceed by preparing the food as for
the cold-pack canning method; also, fill the jars with fruit or
vegetables and with liquid or sirup as in this method. Put the covers on
the jars loosely, omitting the jar rubbers. Place the jars in a shallow
pan of water, as in Fig. 21, and set the pan containing the jars into a
stove oven, which should be only slightly warm. At the same time place
the jar rubbers in a pan of boiling water, so that they may be
sterilized as the food cooks. When the jars are in the oven, increase
the heat gradually until the food in them boils. Then keep up a
temperature that will allow the food to boil quietly for a period long
enough to cook it soft and sterilize it. Usually, 30 to 45 minutes after
boiling has begun will be sufficient. During the cooking some of the
liquid in the jars evaporates. Therefore, when the jars of food are
ready to be removed from the oven, have boiling water or sirup ready,
remove the cover of each jar in turn, and fill the jar brimful with the
liquid. Then place a sterilized rubber in place and fasten the cover
down tight. The procedure from this point on is the same as in the other
canning methods.
[Illustration: FIG. 21]
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