Oyster sauce is a thick, savory condiment commonly used in Chinese, Vietnamese, Thai, Malay, and Khmer cuisine that is made by cooking oysters. Traditionally, oysters are slowly simmered in water until the liquid caramelizes into a viscous, dark black-brown sauce. However, to speed up the process, some commercialized versions are instead made with oyster extracts, plus salt, sugar, corn starch, and caramel coloring. According to Lee Kum Kee, one of the most famous makers of oyster sauce, the condiment was accidentally invented in the Guangdong province of China by its founder, Lee Kum Sheung, when he overcooked oyster soup. In 1888, he created Lee Kum Kee to sell the sauce, and the company is thriving to this day.

The flavor of oyster sauce is gently salty and briny, with a velvety smooth, thick texture. It is commonly used in Asian dishes, such as stir-fries, marinades, and dipping sauces, and it brings rich, savory flavor to whatever it is poured over or into. Oyster sauces flavor is somewhere between fish sauce and soy sauce, and its consistency is thick and syrupy, and its dark brown in color.

In addition to oyster extracts, sugar, salt, and water, commercial oyster sauce may also contain corn starch, soy sauce, monosodium glutamate, and caramel coloring. Vegetarian versions of oyster sauce are usually made of the same ingredients but instead of oysters, there are soybeans, brown sugar, and mushroom flavor.

In summary, oyster sauce is a thick, savory condiment made by cooking oysters, and it is commonly used in Asian cuisine. It has a gently salty and briny flavor, and its consistency is thick and syrupy, and its dark brown in color. Commercial oyster sauce may contain corn starch, soy sauce, monosodium glutamate, and caramel coloring, and vegetarian versions are usually made of soybeans, brown sugar, and mushroom flavor.