Love them or you may be repulsed by them, either way, there is probably much you don’t know about the beloved bivalve mollusk called an oyster. So, here’s a brief lesson on the culinary evolution of oysters, and a few other interesting facts to entice friends at the next trivia event.
According to Wikipedia, “Oyster is the common name for a number of different families of salt-water bivalve mollusks that live in marine or brackish habitats”. The word oyster is derived from the French word “oistre”, and first appeared in the English language during the 14th century as oyster.
Oysters are filter feeders, and can be found adhering to rocks or other fixed objects in shallow saltwater areas or in brackish water in the mouth of rivers. They draw water in and transport plankton and various particles through a gill to a “mouth” where they extract nutrients and filter pollutants. An oyster can filter over 1 gallon of water per hour, removing excess sediments, algae and other impurities from waters. Oysters are also hermaphrodites and change sex based on their life stage.
Oysters have been consumed by humans for hundreds of thousands of years. One of the earliest records of human consumption of oysters dates to a land off the southern coast of Africa called Pinnacle Point. According to an article posted by NPR.org, “Scientists exploring a cave in South Africa report evidence of shellfish dinners enjoyed by humans who lived 164,000 years ago”.
Oysters are thought to be first cultivated by humans in Japan around 2000 BC. Early Romans may have been the first to commercially farm oysters for food using sophisticated cultivation systems such as channels and locks to control tides to harvest them. Early Evidence of oyster cultivation in the US has been found at the shores of New York City, where the area was covered in oyster beds by native Lenape Indians. Manhattan’s oldest street, Pearl Street, is named so because it was covered with crushed oyster shells.
Commercial oyster cultivation and sale began to boom in the US. around the early 19th century. At that time, oysters were so plentiful in New York that raw oysters could be purchased from street vendors and were eaten mostly by the working class because they were so inexpensive. Oysters are now widely popular across the US. From Seattle to Apalachicola, oysters can be found in a variety of restaurants and markets, and prepared or eaten in almost as many ways.
So now here are a few answers about questions that you may be asking:
Should oysters only be eaten in a month with an R in it? The answer is No. Today, barring immune deficiencies or health issues, commercially harvested shellfish from restaurants and retailers is safe to eat year-round. The “R” rule, which singles out the warmer months of summer (May to August), is an outdated rule. Refrigeration units are now available at the point of harvest, and although summer tends to be the time when there are algae blooms, red tides, and higher counts of bacteria in the water, oysters are tested often and strict regulations force closing of shellfish areas to avoid potential foodborne risks. Also, unlike most shellfish, oysters can have a fairly long shelf life of up to four weeks (although they lose their fresh taste and tend to get a hard texture as they get older). Note: Oysters should be refrigerated out of water, not frozen, and in 100% humidity. Oysters stored in water under refrigeration will open, consume oxygen, and die.
Are oysters good for you? Yes. Oysters are a healthy food choice. They contain a variety of vitamins and nutrients including zinc, calcium, magnesium, protein, selenium, and vitamin A. They also contain high levels of vitamin B12, iron and monounsaturated fat – the “healthy” kind of fat that you also find in olive oil.
How many types of oysters are there? In the U.S. alone, there are several hundred varieties of oysters, but there are only 5 edible species. The five edible species of oysters are:
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Pacific: These are the most commonly cultivated oyster on the US Pacific Coast, although they are not native to the region. Pacific oysters were brought to the US from the Asian Pacific in the early 1900’s and are now the world’s most cultivated oyster.
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Eastern or Atlantic: They represent nearly two-thirds of the US domestic harvest. They flourish in a wide variety of conditions (from Long Island Sound to the Gulf of Mexico), and vary in taste based upon the region in which they were harvested. Varieties of this oyster include the popular Blue Point, Chincoteague, Apalachicola, and Cape Cods.
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Kumamoto: These oysters are beach-grown at the very bottom of Puget Sound. Originally imported from Japan, and like the Pacific, this oyster and has a high tolerance for temperature fluctuation and salinity changes.
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European: This species is originally from Europe but are now found in Maine, where there are self-sustaining wild reefs for cultivation. These are said to be the oysters that the ancient Romans and Gauls ate.
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Olympia: This is the only native West Coast oyster. It is harvested commercially and only in the southern Puget Sound. It has a low tolerance for temperature, salinity and environmental fluctuations.
Of the 5 species, there are 3 primary factors that make each unique:
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Environment: Local habitat, water salinity and temperature. Since oysters filter water for their food, it goes without saying that they taste like the environment they live in. So, an oyster grown in freshwater will be less briny than an oyster filtering salty ocean water, etc.
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Method of growth: Some oysters are grown in hanging bags so that they never touch the ocean bottom and are forced to tumble, producing a smooth mussel-like shell. Others are grown on the surface of the water in “floats”, or in bottom of the seas in cages” or beds. A farm may grow only one species in one location but use different growing techniques so that they can create multiple varieties.
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Branding: Branding is simply a commercial business play on an identical species. Branding of oysters allows more oysters to have a market “niche” for the grower. According to Les Barnes, Owner of London Lennie’s Raw Bar, “If a fresh water river is near the harvesting area, use the river name; if it’s from a salt pond, use that name; if it’s near a town, then that should be the name or a body of water, and so on.”
How do I know if an oyster is alive? A living, unshucked oyster will be fully closed and near impossible to open without the proper knife and technique. If the oyster is cracked open, a tap on the shell or a poke at the gill will force it to close if it is still alive. Oysters should only be eaten raw or cooked prior to consumption while they are alive.
How are oysters eaten? There isn’t a right way to enjoy oysters, but I highly encourage to try eating them raw first so that you can actually taste the oyster before slathering it with cocktail or other sauces. Also, if there are more than one variety available, try at least two so that you can taste the differences. There are several methods of preparing oysters. Once you have tried them raw, try them grilled, baked, fried, sautéed, stewed, etc.
Do oysters have pearls? Not all types of oysters make pearls. Despite any hopes you have of popping open an oyster and finding a pearl, edible oysters don’t actually make “pearls” per-se. The pearl-producing kind belongs to Pterioida while the oysters you order from a menu are Ostreid. And then again, most pearls found in jewelry are from clams and mussels – not oysters. Does the bad oyster exist? Sometimes, yes. The bad oyster is a real thing, and the best way to avoid it is to avoid eating raw shellfish that has been sitting out for a while in a warm room or in the sun. But even if you are cautious, you can still get sick off of oysters. The reason for this is food poisoning from vibrio vulnificus, a bacterium that grows in estuaries and along the coast that can occasionally end up in oysters and effect you if eaten raw. But most people that end up with dreadful illness seem to recover just fine. I, being one of them! Are oysters an aphrodisiac? There is no real proof that oysters are an aphrodisiac. They contain phosphorus, iodine, and zinc, which may increase human stamina and aid in production of testosterone. However, no verified studies have determined that these nutrients increase libido. But alas, it may be the overall appearance of an oyster that leads to another factor…. Food for thought! ????