Mussels are very similar to clams in both appearance and taste. They are bivalves which mean they have two shells which are hinged, allowing them to open and close. Unlike clams they have a beard at their hinge area which allows them to attach themselves to underwater structures. Their shell is brittle like a soft shell clam, is black or bluish-black in color and averages 2-4 inches in length. They can be found in freshwater and saltwater but generally only the saltwater version is eaten. The most common varieties used for food are the green mussel and the blue mussel. The blue mussel is found in the wild and is farmed on the west and the east coast of the United States, with the state of Maine being the biggest contributor. The green mussel is generally a farmed version from New Zealand.
They are a relatively inexpensive food because of their abundance but they do not have a very good keeping quality. If using raw mussels in the shell only use live ones. They can also be found on the market frozen and precooked in the shell. To check to make sure they are still alive, tap two of them together. If one of them sounds hollow, don’t use it. Any shells that are opened should close when you touch them. You can try pinching the shells together. If they stay closed tight they are good to use. If you buy them in the shell allow about 6 medium size per person and if buying shucked allow 4-6 ounces per person. Before cooking place live mussels in a pot of cold water for about 2 hours. Do not use any that float. They are easily opened with a knife inserted between the shells but any of the methods used for clams and oysters will also work. Remove the beard from the mussels, and scrub the shell before cooking. If you are buying them shucked, they should have a slightly sweet, fresh smell. Keep them in the refrigerator for no more than 2 days. The meat can range from yellow to reddish and is sweet with a firm texture. Mussels can be eaten raw, baked, poached, steamed, pan fried, broiled, sautéed, deep fried, grilled or used in soups and stews. The most common way of cooking is steaming. For instructions on cooking mussels click the following link. How to cook mussels.