Hoisin sauce is a thick, reddish-brown, sweet-hot sauce made of soybeans, garlic and chiles. Popular in Chinese cuisine, hoisin sauce is used as a condiment as well as to flavor a variety of foods. Hoisin sauce keeps indefinitely in the refrigerator. Bottles and jars of the sauce can be refrigerated as is. Canned sauce must be transferred to a non-metallic container for storage.