Liverwurst's primary ingredients include pig or calf liver mixed with pork, veal or beef. In the United States, any meat labeled "liverwurst" must contain at least 30 percent liver by weight. Liverwurst also contains a variety of spices that may include pepper, thyme, allspice, nutmeg and ground mustard seed.
Outside of the liver requirement, liverwurst recipes can vary significantly. Many recipes include added fat or bacon to improve the texture and flavor of the final product. Liverwurst may be made entirely of beef, entirely of pork, or may contain a variety of meats including sheep and goat livers. Onion is a common addition, as are more exotic ingredients like beef tongue or pistachio nuts. Manufacturers may also blend the meat mixture into pate or dip instead of injecting it into casings and may smoke it as a final step.
If liverwurst contains only beef or pork, manufacturers may label it as "braunschweiger." Typically, braunschweiger includes bacon as a flavoring agent as well as white pepper, mace, and either chopped onion or onion powder. Manufacturers usually stuff braunschweiger into natural casings, and it is almost always smoked during the curing process.
Liverwurst and braunschweiger originated in Germany, but have become popular foods throughout Europe and the Americas.