Unlike jelly, which is made from fruit juice, other sugar-preserved foods contain parts of the whole fruit. Fruit butter is mashed pulp simmered with sugar until the pulp is thick; in the other fruit products pieces of fruit float in a light gel. Jam consists of gelled, mashed pulp; preserves are made of fruit pieces in a thin gel; and marmalade contains bits of fruit and citrus rind in a stiff, clear gel. Conserves have a higher percentage of chopped, mixed fruits in a small amount of jellied juice; nuts are often stirred into the gel just before it starts to set.

In all these products, with the exception of the fruit butters, the amount of sugar, natural pectin, and acid are critical to proper texture, particularly if additional pectin is not being added. As in making jelly, best results are achieved by following a recipe carefully – do not double or triple ingredient measures to make a bigger batch. Instead, make several small batches. Be sure pectin and acid content are high enough by using plenty of under ripe high-pectin fruit or by testing for pectin and acid. You can tell if the sugar concentration is correct by measuring the temperature of the sugar-fruit mixture as it cooks. First, find the temperature at which water boils (which will vary depending on your altitude). Then cook the fruit and sugar until it reaches 8 to 10 degrees F above the boiling point of water. If you do not have a thermometer, use the freezer test. When making jams or other fruit products with added pectin, you need not cook measurements and accurate timing are still important.

Jams, marmalades, preserves, conserves, and butters must undergo further processing in a canner to eliminate spoilage causing organisms if the product is to be stored for more than two or three weeks. Certain recipes specify freezing; all others require canning by the boiling water bath technique. Use hot, sterile canning jars, and leave a 1/2 inch space above the fruit.