Oyster sauce is a viscous sauce prepared from oysters and brine, often with chemical preservatives added. It is much used in Chinese cooking. The sauce is often used as a topping for steamed vegetables such as kailan and in stir-fried food.
History
Oyster sauce is said to be invented in 1888 by Mr. Lee Kam Sheung, in Nam Shui Village in Guangdong Province, China. His company, Lee Kum Kee, continues to produce oyster sauce today.
Vegetarian oyster sauce prepared from mushrooms, is also popular and generally cheaper.
Making Oyster Sauce
A 'True' oyster sauce of good quality should be made by condensing oyster extracts (which is made by cooking oysters in water, where the aqueous mixture is then cooked until a desired viscosity has been reached ) alone and no other additives except salt. The sauce should be aromatic with great flavour. Sadly, however, this would be costly and only a handful of manufacturers are willing to do so. Quite a number of oyster sauces are actually diluted solution of concentrated ones.
The use of Oyster Sauce
Oyster sauce is capable of enhancing flavour of other food. A tablespoon of it makes plain Chinese noodles no more oridinary.
Typical oyster sauce has MSG added, but in recent years MSG-free varieties can also be found. The differences (in terms of taste) between MSG and non-MSG variants maybe indistinguishable.