77. The chief difference between the canning of fruits and the canning
of vegetables is that sugar in the form of sirup, instead of salt water,
is used for the liquid. Fruits may be canned without sugar if desired,
but nothing is gained by so doing, for sugar will have to be added
later. Because of the sugar used in canning and the acid contained in
the fruit, canned fruit has better keeping qualities than canned
vegetables. In fact, it is much more likely to keep well even though it
does not receive such careful attention as vegetables. It is for this
reason that canned fruit does not require so much time for sterilization
as vegetables do. Still it should not be inferred that care is not
necessary in the canning of fruits. Indeed, the more care that is taken,
the better are the results likely to be.
78. SIRUPS FOR CANNING.--Before the canning of fruits can be undertaken,
it is necessary to possess a knowledge of the sirups that are needed.
Such sirups consist simply of sugar dissolved in boiling water. The
quantity of sugar and water required for a sirup depends on the acidity
of the fruit and the purpose for which it is to be used. Plain canned
fruits that are to be used for sauces, etc. require less sugar
proportionately than those which are preserved, and fruit canned for pie
making may have less than either. Thus, fruits of the same kind may be
canned with sirups of different proportions. To a great extent, the
quantity of sugar to use with fruit may be regulated by the taste, but
it will be readily seen that such fruits as sour cherries and plums will
require more sugar to make them palatable than pears and blueberries. It
will be well to note, though, that the sugar does not penetrate the
fruit unless the two are cooked together.
79. In order to make sirup for canning, place the desired quantities of
sugar and water in a kettle and proceed to heat them. Stir the liquid
while it is heating, in order to assist in dissolving the sugar. When it
has begun to boil rapidly, remove the sirup from the fire and use it at
once. Do not continue boiling.
In preparing such sirups, it will be well to note that the greater the
proportion of sugar to water or the longer the sugar and water are
allowed to boil, the denser, or heavier, will the sirup become. It is
this _density_ of sirup that regulates its use for the different kinds
of fruit and determines its nature. Thus, a sirup in which the
proportion of sugar to water is so large as to make the sirup thick is
known as a _heavy sirup_; one in which the proportion of water to sugar
is so large as to make the sirup thin is called a _light sirup_; and one
in which the proportion of sugar and water is such as to produce a sirup
that is neither thick nor thin, but stands between the two extremes, is
called a _medium sirup_.