Tallow is a fatty substance used in many products. It is obtained by rendering (melting) and refining the fat of cattle, goats, or sheep. Tallow is classified as either edible or inedible. Edible tallow is used primarily as an ingredient in shortening for cooking. Most inedible tallow produced in the United States is used to make animal feed, such as cattle feed and pet food. Inedible tallow is also chemically treated to make soaps and detergents (see Detergent and soap (How detergents are made) ). Edible tallow is white and almost tasteless. Inedible tallow may be white, yellow, or brown.
Tallow is an important source of certain fatty acids. About half the fatty acid molecules in tallow are saturated–that is, they contain as many hydrogen atoms as possible (see Fat ). Fatty acids obtained from tallow are used to make hundreds of everyday products, including automobile tires, cosmetics, detergents, lubricants, and plastics. These acids can do the job of many of the chemicals ordinarily manufactured from petroleum. Therefore, tallow can help conserve the limited supply of petroleum in the world.