In making jams, the fruit should be carefully cleaned and thoroughly bruised, as mashing it before cooking prevents it from becoming hard. Boil fifteen or twenty minutes before adding the sugar, as the flavor of the fruit is thus better preserved (usually allowing three-quarters of a pound of sugar to a pound of fruit), and then boil half an hour longer. Jams require almost constant stirring, and every house-keeper should be provided with a small paddle with handle at right angles with the blade (similar to an apple-butter "stirrer," only smaller), to be used in making jams and marmalades. Jams are made from the more juicy berries, such as blackberries, currants, raspberries, strawberries, etc.; marmalades from the firmet fruits, such as pine-apples, peaches and apricots. Both require the closest attention, as the slightest degree of burning ruins the flavor. They must be boiled sufficiently, and have plenty of sugar to keep well.
To tell when any jam or marmalade is sufficiently cooked, take out some of it on a plate and let it cool. If no juice or moisture gathers about it, and it looks dry and glistening, it is done thoroughly. Put up in glass or small stone jars, and seal or secure like canned fruits or jellies. Keep jellies and jams in a cool, dry, and dark place.