The Coffin Bay king oysters are the most expensive in the world. Coffin Bay is located on the West Coast of Australia where the oysters grow for six years. For other varieties this is normally not more than 18 months.
You can buy them in Australia and a few select places in the EU and Asia) for more than 50 euro per oyster. The fact that they have around 10 times more meat compared to ‘normal’ oysters, compensates this high price partly.
But what about other varieties? Oyster is a salt-water mollusc that lives in the sea or in brackish water. Many people around the world eat them raw or cook them. They considered it to be a delicacy.
In some countries fishers harvest oysters for the pearl produced within the oyster or – in the case of windowpane oysters – for their translucent shells.
The word “oyster” appeared in English in the 14th century. It is from Old French ‘oistre’ (today: huitre), which again is from the Latin ostrea, which in Greek was ὄστρεον (ostreon).
Types of Oysters
- True oysters include the edible ones, like the European flat oyster, eastern oyster, Olympia oyster, Pacific oyster, and the Sydney rock oyster.
- Pearl oysters contain pearls. However, many are not that valuable. Pearls can form in both saltwater and freshwater and the combination thereof, brackish water. The largest pearl-bearing oyster has the size of a dinner plate. Pearl oysters produce pearls by covering a minute object which invaded the oyster with ‘nacre’. Over the years, layers of nacre cover the object until it becomes a pearl. The pearl can have different colours and shapes. This depends on the natural pigment of the nacre, and the shape of the original object.
- Thorny oysters
- Pilgrim oyster, or ‘scallop’, referring to the St. James scallop shell
- Saddle oysters, or jingle shells
- Dimydarian oysters
- Windowpane oysters
- Tikod Amo, local thorny oyster species and a favorite seafood in the southern part of the Philippines. Because of its good flavor, it is quite expensive.
Health Benefits of Oysters
Oysters contain a lot of zinc, iron, calcium, and selenium, as well as vitamin A and vitamin B12. Two oysters (28 g) provide the Reference Daily Intake of zinc and vitamin B12.
Oysters are low in food energy and one raw oyster contains about 10 kilocalories (less than 40 kJ).
They are rich in protein (approximately 10 g in a dozen of Pacific oysters).
Traditionally, people around the world have considered oysters to be an aphrodisiac. Partially because they resemble female sex organs. But it is not only their look. American and Italian researchers found that they are rich in amino acids that triggers sex hormones. Their high zinc content aids the production of testosterone.
Habitat and behaviour
A group of oysters is commonly called a bed or reef. Some tropical oysters, such as the mangrove oyster, grow best on mangrove roots. Low tide can expose them, making them easy to collect.
The largest oyster-producing location in the United States is Chesapeake Bay. Although these beds have decreased in number due to overfishing and pollution.
Willapa Bay in Washington produces more than any other estuary in the US. Other large farming areas in the US include the bays and estuaries along the coast of the Gulf of Mexico from Apalachicola, Florida in the east to Galveston, Texas in the west.
Large beds of edible oysters are also located in Japan and Australia. In 2005, China accounted for 80% of the global oyster harvest. Within Europe, France is the industry leader.
Archaeologists have found refuse heaps (‘middens’ originating from prehistoric times in Australia and in Japan from at least 2000 BC. In the United Kingdom, for instance in Kent, the middens originate from Roman times.
There are several oyster festivals in the United Kingdom like for example, the September Woburn Oyster Festival and Colchester Oyster Feast in October.
In France it is especially Cancale in Brittany where they have been cultivated since Roman times.
The Romans used methods and systems like hydraulics, locks for tide control, to cultivate oysters which we still use today.
Oysters were not always one of the most expensive foods. Two centuries ago, they were cheap and mainly consumed by the working class.
Also two centuries ago, New York Harbor was the largest source of oysters worldwide. They produced six million per day. Eventually, too high demand meant they had to increase production. So they introduced foreign species. But with them came new disease. This and sedimentation destroyed most of the beds by the beginning of the 20th century.
From that moment onward, their popularity have caused increasingly higher demands on wild oyster stocks. This has increased prices. Today they are not more a working-class but an expensive delicacy.
Today, the larger Pacific and rock oyster varieties – which are available year-round – dominate the current market.
Fishing and cultivating oysters
Farmers or divers harvest oysters by gathering them from oyster beds or reefs. The use of dredges can heavily damage the oyster beds. Therefore countries have restricted their use.
The oyster farmers sort and eliminate dead oysters and other animals, by-catch , and dirt and then sell the (still alive) oysters on the market.
In many countries, farmers introduced non-native oysters to compensate for insufficient harvests of native varieties. Such introductions remain controversial.
The introduction of non-native species by humans negatively affects native oyster populations. For example, in the US the introduction of non-native species in Tomales Bay resulted in the loss of half of California’s Olympia oysters.
The myth of the ‘r’ in the month
Once in a while we still hear that you can only eat oysters in months with the letter ‘r’ (in their English and French names). This myth is partly true in countries like France or the USA . In the warmer months of May, June, July, and August they spoil easily.
Jonathan Swift said, “He was a bold man that first ate an oyster”. In prehistory people already consumed theem. Especially in coastal areas they were an important source of food. Oyster fisheries still are an important industry. Especially in areas where there are many oyster beds or reefs. Overfishing, diseases and pollution have caused a sharp reduction. The decreased supply causes the prices to be higher. But they continue to be a popular dish. And there are many oyster festivals in many cities and towns where oysters are cultivated or fished
Dishes and Recipes
They can be eaten on the half shell and raw (witgh champagne!). But also smoked, boiled, baked, fried, roasted, or stewed. They are canned, pickled, steamed, or broiled. And even used in drinks. Eating can be as simple as opening the shell and eating the contents, including juice. Often people add butter and salt. A nice and tast dish is poached oysters on toast with a cream roux.
Purists insist on eating them raw. No dressing except maybe for a drop of lemon juice or shallot vinegar.
Upscale restaurants pair raw oysters with mignonette sauce. They make this with fresh chopped shallot, mixed peppercorn, dry white wine and some lemon juice or sherry vinegar.
Like fine wine, raw oysters have complex flavors that vary greatly among varieties and regions: salty, briny, buttery, metallic, or even fruity. The texture is soft and fleshy, but crisp on the palate.
Jewish and some Islamic dietary laws forbid the eating of oysters..
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 5 cm (2.0 in) long.
While different methods are used to open an oyster (which sometimes depend on the type), the following is one commonly accepted method:
- Insert the blade, with moderate force and vibration if necessary, at the hinge between the two valves.
- Twist the blade until there is a slight pop.
- Slide the blade upward to cut the adductor muscle which holds the shell closed.
Inexperienced shuckers can apply too much force, which can result in injury if the blade slips. Theren it is better to wear heavy gloves. Not only the knife, but also the shell itself is razor-sharp. If you are a professional shuckers, you only require up to three seconds to open the shell.
If the oyster has a particularly soft shell, the knife can be inserted instead in the “sidedoor”, about halfway along one side where its lips widen with a slight indentation.
Opening or “shucking” oysters has become a competitive sport. There are even competitions around the world!
Food safety and storage
Surprisingly, and unlike most shellfish, oysters can be stored up to four weeks. However, the older the more their taste becomes less pleasant . Also fresh oysters must be alive when consumed raw or just before cooking.
Oysters that do not open before cooking are most probably dead and therefore unsafe. The oyster must be capable of tightly closing its shell. You do that by tapping them on the shell. A live oyster will close up. If they are open and unresponsive, they are dead and must be thrown away.
They can also contain harmful bacteria, since they are filter feeders. They will naturally absorb anything present in the surrounding water. In these cases, the main danger is for individuals with reduced immune systems.