Nutrition Notes
Oysters are good source of protein, they are low in fat, and provide plenty of iron and zinc as well as some calcium. If you're not eating oysters raw with just a squirt of lemon juice, however, the nutriton values can change drastically (e.g. with butter, cream sauce, etc.).
Eastern Farmed Oysters (raw)
A serving of 6 medium oysters (approximately 84 grams) provides 50 calories, 4 g protein, 1.3 g fat (<0.5 g saturated), 150 mg sodium, 21 mg cholesterol, is an excellent source (>25% DV) of iron, zinc, copper, selenium and vitamin B12, and a source (>5% DV) of magnesium, phosphorus, folate, vitamin C and thiamin. They also contain some calcium.
Eastern Wild Oysters (raw)
A serving of 6 oysters (approximately 84 grams) provides 57 calories, 6 g protein, 2 g fat (0.65 g saturated), 177 mg sodium, 45 mg choleseterol, is an excellent source of iron, copper, selenium and vitamin B12, and a source of phosphorus, vitamin C, thiamin and riboflavin.
Their claim to fame, though, is zinc, a mineral that helps the immune system fight off invading bacteria and viruses, assists in wound healing and is used to make DNA in cells. Six medium oysters have 33 mg of zinc, three day's worth for men and four day's worth for women.
Pacific Oysters (raw)
A serving of 3 oysters (approximately 85 grams) provides 69 calories, 8 g protein, 2 g fat (<0.5 g saturated), 90 mg sodium, 42 mg cholesterol, is an excellent source of iron, zinc, copper, manganese and selenium, and a source of magnesium, phosphorus and vitamin C. They also contain some calcium.
Varieties
There are numerous species of oysters, and the ones you find at your local grocer's are likely the ones that are cultivated closest to where you live. This is because shipping costs typically run too high for moving oysters far from their beds.
Malpeques Oysters
These oysters are grown in PEI and have a reputation as one of the world's finest species. Their appearance, taste and keeping qualities are excellent, with a clarity and purity of flavour in its liquor.
European Oysters
These oysters are attractive for their rounded shells and more regular appearance than the Portuguese oyster.
Portuguese Oysters
These oysters are larger than European oysters, and are also known as giant Pacific oysters, with a maximum length of about 17 cm. In the United States, three oyster species are predominant for commercial harvesting: Pacific or Japanese; Eastern or Atlantic; and the Olympia.
Olympia Oysters
These oysters are rarely larger than 1-1/2 cm and are harvested from Washington's Puget Sound.
Pacific or Japanese Oysters
These are found along the Pacific seaboard and can reach up to a foot in length.
Atlantic or Eastern Oysters
These are considered culinarily superior to Pacific oysters.
Related Oyster Products
Oyster Crabs are small (less than 1" wide) soft-shelled crabs that make their homes inside oysters, living off the food their host eats. They are not found in all oysters, and most processors don't collect them during shucking, making them hard to find, with gourmets considering them a delicacy. They are pale pink in colour and are best simply prepared, sautéed in butter.
Oyster Sauce is a dark-brown sauce made from oysters, brine and soy sauce. It is thick and concentrated, imparting a rich flavour to dishes. It is popular in Asian dishes and as a table condiment.
Buying
Fresh oysters are available year-round. Live oysters are best as fresh as possible, so opt for a store with good turnover and which keeps their oysters chilled at all times. Shells should be undamaged and tightly closed or, if gaping, should snap shut when tapped. Oysters that are small for their species are younger and more tender.
Fresh, shucked oysters should be plump, uniform in size, have good colour, smell fresh and pleasant, and the oyster liquor they are packaged in should be clear, not cloudy.
Oysters are also available frozen, smoked and canned. Canned oysters may be packaged in water or their own liquor.
Storing
Use oysters shortly after purchasing: the sooner they're used, the better they will taste. To store, cover live oysters with a damp towel and refrigerate, with the larger shell down, up to three days.
Shucked oysters should be refrigerated in their liquor and used within two days.
Canned oysters can be stored, unopened, for up to a year in a dry, cool place. Once opened, wrap well and refrigerate the unused portion for up to two days.
Preparing
Oysters in the shell can be served raw, baked, steamed, grilled or incorporated into dishes. Shucked oysters can be batter-fried, sauteed, grilled, used in soups or stews, dressings, poultry stuffings or appetizers.
Eating
Oysters are a versatile seafood. They can be baked, steamed, poached or grilled in the shell. They are also used in specialty dishes such as Oysters Pommary or Florentine while in the shell. Shucked oysters can be deep-fried, sautéed, grilled, in chowders, soups, stews, pies, casseroles, stuffings, dressings, as appetizers and main courses.
The simplest way to prepare oysters is to serve them raw in the shell, with a squirt of lemon juice. Shuck them first so that they can be easily slid out of the shell and enjoyed.
Did You Know?
- The theory that suggests limiting oyster consumption to months with an "R" in their name is no longer applicable. This rule of thumb may have been helpful prior to the days of reliable refrigeration, when the heat of R-less months such as June and July threatened to spoil oysters during shipping and storage.
- For a good read about oysters, Eleanor Clark's The Oysters of Locmariaquer is "at once scientific and poetic" as well as informative, according to Alan Davidson, author of The Penguin Companion to Food (Penguin, 2002).