Nutritionally, oysters are high in protein, low in fat, and contain minerals such as zinc, calcium, iron, copper, iodine, magnesium and selenium.
Buying and storing fresh oysters
Oysters should always be bought live. Choose specimens whose shells are clean and bright, tightly-closed and unbroken. They should feel quite heavy as they should be full of liquor. Once opened, any specimens which look blackish or shrivelled with little liquor should be rejected. A prime oyster should be firm textured with a light brown or greyish colour, a white muscle, juicy with a fresh briny odour.
Bear in mind that size and shape vary considerably although in general. Pacific or rock oysters tend to have a frillier shell and smaller, milder meat than the superior British native oyster.
Live oysters can be stored for a short time on ice, on a damp cloth or in the fridge covered in wet kitchen towels, for a couple of days. Do not store in an airtight container or in fresh water as this will cause them to die. All Oysters should be kept with the rounded part of the shell facing downwards.
Shucked oysters i.e. oysters which have been removed from their shells, can be kept refrigerated in a sealed container for four or five days. They can also be frozen although these are best for cooking rather than eating raw.
Preparing and cooking fresh oysters
The act of opening oysters is called shucking and requires practise and patience until you get used to it. It’s also easier if you have a special oyster knife although a a wide, short, sturdy screwdriver also works. To shuck an oyster, you need to protect your hand with a work glove or hold the oyster in a folded tea towel – deeper shell downwards – then insert the oyster knife between the two halves of the shell and gradually prise apart, working your way around to the hinge. Work over a large plate so you catch as much liquor as possible. Alternatively, you can ask your fishmonger to open them for you, requesting the shells and liquor if required.
Raw oysters are best with a squeeze of lemon juice or a couple of drops of Tabasco sauce. They can be cooked in many ways including grilling, poaching, baking, steaming and boiling.