Fernet Branca is the best-known brand of the fernet category of amari, or bitter herbal liqueurs. It dominates the category to the point it has become nearly synonymous with it. It’s also so popular among drinks-industry workers that it’s often called the “bartender’s handshake.” It’s made with 27 herbs, roots and spices—its recipe is a closely guarded secret—and spends at least 12 months aging in Croatian oak barrels.