Oyster Sauce: What It Is, How to Use It and Substitutes
What is oyster sauce?
Oyster sauce was originally made by boiling down the cooking liquid from oysters until only a dark, syrupy mass was left. Its invention is credited to the cook Lee Kum Sheung, who ran a small food stall in Nanshui in Guangdong province. In 1888 he founded the company Lee Kum Kee to sell the sauce. Today it is usually made from oyster extract, water, sugar, salt and starch. Caramel gives it its dark colour, and many brands also add flavour enhancers. The amount of oyster extract varies a great deal between makers and is not always stated on the bottle. Cheap sauces taste mainly sweet and salty, while better ones have more depth. There is also vegetarian oyster sauce based on shiitake mushrooms. Oyster sauce has little in common with fish sauce: it is thicker and sweeter and barely smells.
Flavour and uses
Oyster sauce tastes salty and caramel-like with a strong umami hit. The taste of the sea is faint. It nearly always goes into the wok at the end, so the sugar does not burn. One tablespoon is enough for one portion. In Beef with Broccoli it thickens the sauce together with soy sauce. Thai street cooks use it for Pad See Ew and for Chinese broccoli, which as Pad Kana Nam Man Hoy is even named after it: nam man hoy is Thai for oyster sauce. In Cambodia it seasons lok lak, and in Mauritius the rice dome bol renversé. Blanched pak choi with a spoonful of oyster sauce and a little garlic oil is the simplest side dish, ready in five minutes.
Buying oyster sauce: what to look for
Most supermarkets stock oyster sauce on the Asian shelf. Asian grocers have a wider choice and cheaper 500 ml bottles. Read the ingredients list: if oyster extract is near the top and water is not listed first, the sauce will be stronger. Many brands offer a standard and a premium range, and the premium one contains more extract. For vegetarians there is mushroom oyster sauce, usually labelled “vegetarian stir-fry sauce” or “vegetarian oyster sauce”. If you want to avoid MSG, check for monosodium glutamate (E621) in the ingredients.
Storage and shelf life
Unopened, oyster sauce keeps for one to two years; the best-before date is on the bottle. Once opened, it belongs in the fridge, where it stays good for about six months. Wipe the neck of the bottle after use, as mould forms there easily. It thickens over time, which does no harm.
What can you use instead of oyster sauce?
For 1 tablespoon oyster sauce, mix 2 teaspoons dark soy sauce with 1 teaspoon hoisin sauce. The mix is a little sweeter but comes close in the wok. Without hoisin, use 1 tablespoon light soy sauce, ½ teaspoon sugar and ¼ teaspoon cornflour, stirred smooth in a tablespoon of water. For vegan cooking, mushroom oyster sauce is the best substitute and can be used 1:1.
