There are two types of sea water oyster readily available in the United Kingdom and most of Europe: rock (Crassostrea gigas) and native oysters (Ostrea edulis). Native oysters (known in France as belons) are small, flattish and circular in shape and with a brownish-green, relatively smooth shell. They are difficult to farm, take four to five years to mature and are not disease resistant. Not only are they more scarce than rock oysters, they are also more highly regarded, with firm flesh and a subtle, delicate flavour.
Rock oysters are relatively abundant; the meat is held in a deep elongated cup with a flat 'lid' and the shells are rugged and warty, covered in coarse textured bumps and crevices. The flesh is less substantial than that of the natives and the flavour sharper, even metallic. When the word 'oysters' is used alone this will almost always indicate rock oysters as, if they are natives, they will invariably be described as such.
Pacific oysters or gigas are also rock oysters, which, when large are rather fatty and most able to bear the addition of Tabasco and such things and, unlike natives, improved by such additives. As in England, where one can assume that an oyster is a rock oyster, so in France one can assume that huîtres are huîtres creuses (also known just as creuses). Despite all this, a good fresh rock oyster from a good site will be delicious. Native oysters are now being raised in the US where belon is also a term which has come to mean any of several European flat oysters raised on the coast of New England.
In general oysters are at their best from the end of October until the end of February, though they are traditionally available in all months with an ‘r’ in them. In summer, when they breed, the flesh becomes milky and sometimes almost sandy. In cool summers rock oysters will fail to breed and they can be eaten all year.
It is a common fallacy that oysters must be eaten straight from the sea. In fact the taste is at its best a day or so later. They will keep in a cool place for up to a week but resist the temptation to place them in water, either saline or fresh, and just cover them with a damp cloth. Don’t freeze them. If you do they must be cooked for eating. As with other shellfish, the test is to give them a light rap with a pencil. They should close. If they do not they should be discarded. If many of the batch fail to close, discard them all and have a cheese sandwich.
Oysters are often eaten in multiples of three, served on ice (which is actually not a great idea as it makes them too cold, but it does stop them tipping up and spilling the liquor). Some people really dislike the combination of butter and oysters, so do not butter the brown bread (US: wheat bread) which is traditionally served with them.
Watch out when buying oysters in Britain where fishmongers are not always well-informed and they may describe something as a 'native' oyster because it was harvested off the British coast. Very few fishmongers actually supply natives.
In France, the expressions ‘fines’ and ‘spéciales’ when applied to oysters describe oysters of a certain desirable weight and dimension, carrying a guarantee of a good meat to shell ratio. Claires are special pens in which oysters are fattened during their growing season and provide oysters of good flavour and with a slightly greenish tinge resulting from the algae-rich waters in which they are grown. ‘Fines de claires’ thus have a guarantee of flavour and weight.
The lower shell should have a cup deep enough to allow the oyster to develop. The flesh should be creamy white and reasonably firm, not watery. The inside of the shell should be shiny white and unblemished. The taste should be that of an essence of the sea.
It is difficult to state what is the best size for an oyster. Britain and France use different numbering systems for sizing both rock and native oysters, the only thing they have in common being that a smaller number indicates a larger oyster. The French system is more formalised than the system used in Britain but, on the whole, the best advice is to chose smaller (but not the smallest) rather than larger oysters, which are inclined to be watery. If in doubt, the best thing to do is not to go for extremes in either direction. Rick Stein's favourite size for a native oyster is No 3 - "Not too big and not too small"
Oysters that have been farmed may sometimes be misshapen, more long and thin and uniform in width than the classic fan shape of the rock oyster. These are sometimes called banana oysters (in France oreilles de lapin) and should be avoided. They are used commercially in prepared stews and soups in the United States.
Another type of oyster to watch out for is the large flat oyster with a coarse, heavy shell which sometimes masquerades as a native, once called scuttle mouths (in France pieds de cheval) both accurately descriptive terms. These are aged ‘wild’ native oysters which have grown unattended on natural beds, unlike the refined managed natives which will have been moved to estuarine waters for fattening. Oyster beds are made and managed.
On 2nd July 1904, Chekhov died in a German spa that was unequipped to care for his illness. He and Olga had travelled there because it was recommended for his health. According to his wife, Chekhov, (a doctor himself), diagnosed his own condition and told the doctor he was dying. The doctor sent for champagne, and then Chekov said, "I haven't drunk champagne in a long time," drank some sips of champagne, turned over on his side and died. His body was returned back to Russia in a train car labelled, "Fresh Oysters," a comic detail Chekhov probably would've enjoyed in the sombre context of his death.
Casanova used to consume 48 oysters for breakfast. They are rich in zinc that is, among other things, a 'key ingredient in sperm'.
