By the word "preserves," we usually understand a fruit preserved in sugar, although, in its general sense, the word means preserving by other means as well. Fruits preserved in sugar are less wholesome than fresh or canned fruits, on account of their extreme sweetness. So much sugar is used in tea and coffee and other ways that the body usually has all it needs without the use of preserves or cake to any great extent. In preserves, the fruit acids seem to be so overcome by the sugar that they exert a less beneficial effect than when the fruit is taken raw, or cooked, and simply sugar enough to sweeten it is used.
Melted paraffine is a good covering for preserves, but there should be a paper tied over the top of the jar to exclude the dust. The paraffine will prevent evaporation to a great extent, and keep them moist on top, even in a warm atmosphere. It is better to heat the paraffine, and pour it over, than to put a piece on top of the preserves to melt, as the heating kills any germs which may be on the wax. In making preserves, the fruit and sugar must be cooked together long enough to thoroughly dissolve the sugar, and prevent it recrystalizing. They should not be boiled together longer than necessary, because the sugar loses so much of its sweetening power. Preserves and jellies should be kept in a dry, cool place.
All solid fruits, such as peaches, pears, etc., should be cooked almost done before the sugar is added. Weigh the fruit before cooking, and use almost an equal amount of sugar. After adding the sugar, cook until the syrup formed from the fruit juice and sugar is as thick as honey. Put the fruit carefully into the jar, and pour the liquid over it.
When soft fruits, such as berries, are preserved, it is impossible to keep them whole unless great care is exercised. It is better to boil the syrup until thick enough, and cook the berries in it just long enough to sterilize them, and evaporate the juice which exudes as they enter the boiling liquid.
Tomatoes, when preserved, should be cooked in the syrup. Ground cherries are also better treated in this way. Quinces are sometimes preserved by cooking until tender, and putting in a sterilized stone jar, a layer of quince and a layer of sugar, using equal amounts of each. The object in doing this is to have a lighter colored product: The quinces must be watched, and if they begin to ferment they must be boiled, as they are not certain to keep, preserved in this way. One-third as much sweet apple as quince may be used in quince preserves without deteriorating the product.
Stone the cherries. For each quart of cherries measure one and one-half pints of sugar. Put the sugar in a saucepan, and pour over it half as much boiling water as there is sugar. Cook until the syrup is thick, then put in juice and cherries, and skim as it cooks until the cherries are transparent. Skim out the fruit into glasses, and when the syrup is thick as honey, pour it over them. Cherries have a better flavor if some of the pits are cooked with them. Measure the cherries before stoning, if preferred sweeter.