Beef bouillon

Beef bouillon (also called beef stock or beef broth) is a liquid made from simmering beef and beef bones with vegetables and aromatics in water until flavor and gelatin are extracted from the meat. 

Beef bouillon is brown in color and clear, with aromas and flavors of beef. Beef bouillon was popular in older cocktails like the Bull Shot or the Bloody Bull, but has faded from popularity with the rise of craft cocktails.