Tallow

Tallow is a rendered form of beef or mutton fat, processed from suet. It is solid at room temperature. Unlike suet, tallow can be stored for extended periods without the need for refrigeration to prevent decomposition, provided it is kept in an airtight container to prevent oxidation.

In industry, tallow is not strictly defined as beef or mutton fat. In this context, tallow is animal fat that conforms to certain technical criteria, including its melting point. It is common for commercial tallow to contain fat derived from other animals, such as lard from pigs, or even from plant sources.

The diagram to the right shows the chemical structure of a typical triglyceride molecule.

Tallow is used mainly in producing soap and animal feed.

Tallow can be used for the production of biodiesel in much the same way as oils from plants are currently used. Because tallow is derived from animal by-products which have little to no value to commercial food industries, it avoids some of the food vs. fuel debate.

The United States Air Force has experimented successfully with the use of beef tallow in aviation biofuels. During five days of flight testing from August 23 to 27, 2010, at Edwards Air Force Base, California, a U.S. Air Force C-17 Globemaster III flew using JP-8 conventional jet fuel in three of its engines and a 50/50 blend of JP-8 and HRJ biofuel made from beef tallow in one engine on 23 August, followed by a flight with the same 50/50 blend in all four engines on 24 August. On 27 August, it flew using a blend of 50 percent JP-8, 25 percent HRJ, and 25 percent coal-based fuel made through the Fischer–Tropsch process, becoming the first United States Department of Defense aircraft to fly on such a blend and the first aircraft to operate from Edwards using a fuel derived from beef tallow.