The evaporation of water and gelling of fruit-based mixtures, results in various jams, jellies, and preserves. Jams typically contain fruit pieces or crushed fruit; jellies are made with the juice extracted from the fruit, and preserves are generally made of the crushed, entire fruit. In this chapter, the term ‘jam’ will be used to refer generally to this product category, except where specified. The gelling agent in the production of jam is pectin. The mechanism of pectin gel formation is complex and depends on factors such as the type of pectin, the pH and temperature, and the soluble solids (Brix) and calcium content of the recipe