There are two processes for inedible rendering: the wet process and the dry process. Wet rendering separates fat from raw material by boiling in water. The process involves adding water to the raw material and using live steam to cook the raw material and separate the fat. Dry rendering is a batch or continuous process in which the material being rendered is cooked in its own moisture and grease with dry heat in open steam jacketed drums until the moisture has evaporated. Following dehydration, as much fat as possible is removed by draining, and the residue is passed through a screw press to remove some of the remaining fat and moisture. Then the residue is granulated or ground into a meal. At present, only dry rendering is used in the United States. The wet rendering process is no longer used because of the high cost of energy and its adverse effect on the fat quality (USEPA 1995).