Choosing a Lively Crab at the Harbour

A harbour market on a bright morning is one of the great pleasures of British coastal life, and the crab stalls are usually where the crowd gathers. If you are buying live crab, look for one that is heavy for its size and feels solid in the hand. A lively crab will tuck its legs under its body and push back against your palm; if the legs hang limp and the eyes do not move, walk on. The shell should be hard all over, with no soft patches, dark spots or a hollow feel when you tap it.

Ask the seller which species you are looking at. Brown crab, sometimes called edible crab, gives generous white meat in the claws and legs plus a rich dark brown meat in the body. Velvet swimming crab is smaller, sweeter and often sold cooked, with vivid blue markings on the legs. Ask, too, whether the crab has been cooked on the boat or at the stall. Cooked crab should smell clean and sea-fresh, never sharp or ammoniacal.

• Heavy for its size, with a hard, unblemished shell
• Legs tucked tight and resisting when you lift it
• No missing claws, which usually means a long spell in a tank
• Cooking smell clean and marine, not sour

Getting It Home and Cooking It Promptly

Live crab does not keep well in a warm car, so take a cool box or an insulated bag with you and drive straight home. Once there, keep the crab cold and damp but never submerged in tap water, which will kill it. A bucket lined with a little seaweed or damp newspaper, placed in the coolest corner of the kitchen or the bottom of the fridge, will hold it comfortably for a few hours. Cook it the same day you buy it; flavour and texture both fade with every hour of waiting.

If you have bought it cooked, keep it chilled and eat it within twenty-four hours. Cooked crab left in the fridge for days turns dry and loses that sweet perfume of the sea that makes harbour-bought crab worth the effort.

How to Cook a Crab Properly

Fill a large pan with enough water to cover the crab comfortably and add plenty of salt — roughly 60g of sea salt per litre. Bring it to a rolling boil, then lower the crab in head first and put the lid on. Once the water returns to the boil, start timing: about fifteen minutes for the first kilogram, then add three to four minutes for each additional 500g. A 1.5kg crab therefore needs roughly eighteen to twenty minutes at a steady simmer.

The shell will turn a deep orange-red when it is done. Lift the crab out and let it cool in the empty pan for twenty minutes or so, which keeps the meat moist, then chill it thoroughly before picking. Cold crab is far easier to shell cleanly than warm crab.

Picking the Meat Without Waste

Work on a large board with a bowl for white meat and a smaller one for brown. Twist off the legs and claws first, then crack each claw with the back of a heavy knife or a nutcracker and prise out the meat in whole pieces. Legs give less, but a rolling pin run along them pushes out neat ribbons of meat — worth the trouble for a sandwich.

Turn the body on its back, pull away the pointed apron, then grip the shell and the body and twist them apart. Scoop the brown meat into its bowl. Remove and discard the feathery grey gills, the small stomach sac just behind the mouth, and the thin intestine running down the middle. Rinse the shell, then pick every scrap of white meat from the chambers with a skewer or a crab pick. Any shell you find can be simmered for a quick fish stock.

• White meat from claws, legs and body chambers
• Brown meat from the main body cavity
• Discard gills, stomach sac and intestine

Three Simple Suppers

Good crab needs very little doing to it. For a salad, fold the white meat gently through a few spoons of mayonnaise with a squeeze of lemon, a little finely chopped celery and plenty of chives, then pile it onto little gem leaves. Keep it loose rather than heavy-handed, and taste before you add salt.

For sandwiches, combine brown and white meat with mayonnaise, a teaspoon of Dijon mustard, lemon juice and black pepper, and spread it thickly on buttered brown bread with a layer of cucumber for crunch. For a buttered toast supper — the best use of a crab, many would argue — warm a generous knob of butter in a pan, add the white meat with a pinch of cayenne and a grate of nutmeg, and stir for barely a minute. Spoon it over hot sourdough and squeeze over lemon.

The brown meat, loosened with a little butter and lemon, is superb spread on toast on its own, and it freezes well in small pots for a future pasta or crab tart.

Keeping Leftovers Tender

Keep white and brown meat separately in covered containers in the coldest part of the fridge and use them within a day. A little oil or mayonnaise stirred through white meat slows its drying. Better still, buy only what you will eat in a sitting or two — the whole pleasure of cooking harbour crab lies in eating it soon, beside a window with the sea still in sight.