It does however, have certain composition limits within which it will set and will be a safe product. Fruit preserves and jams are divided into two groups, generally the berries and the pomes. Those made from the berry group require 47 parts by weight of the fruit component to 55 parts of the sugar. The weight of the sugar component is the weight of the sugar solids. However, the weight of the fruit component is not so easily determined.
Individual fruit can vary widely in solids.
In addition, the fruits, purees and juices used in the manufacture of these products are often concentrated. The regulation provides for the calculation of the weight of the fruit component by listing numerical factors to calculate the pounds of fruit at a standard solids level. An example should suffice. The law requires jelly to be 45 parts by weight juice to 55 parts by weight sugar. Multiply the percent solids by the weight of the ingredients and divide by 100.