Oyster sauce salt, should be added to the sauce, since the oysters should provide all the savoury flavour. However, this method is prohibitively expensive. Many modern oyster sauces are thickened with cornstarch, flavoured with oyster essence or extract and darkened with caramel. Vegetarian oyster sauce prepared from mushrooms, often oyster mushrooms or shiitake mushrooms, is also popular and generally lower in price. It may contain more taste enhancers if less mushroom extract is used to reduce costs. Most of the oyster sauces available on the market contain added monosodium glutamate (MSG). In recent years MSG-free varieties can also be found. The taste
Oyster must be discarded. Some dead oysters, or oyster shells which are full of sand, may be closed. These make a distinctive noise when tapped, and are known as "clackers". Opening oysters, referred to as "oyster-shucking", requires skill. The preferred method is to use a special knife (called an oyster knife, a variant of a shucking knife), with a short and thick blade about long. While different methods are used to open an oyster (which sometimes depend on the type), the following is one commonly accepted oyster-shucking method. Inexperienced shuckers can apply too much force, which can result in injury if