It might seem like a lot of fuss to prepare crab, but it's much cheaper than lobster, and gets easier and quicker with practice. Michael Raffael offers recipes and advice from Tommi Tuhkanen, head chef at Rathmullan House, Co Donegal
Crab costs a third of the price of lobster, often a lot less. Many chefs prefer it. So why not use it more? Maybe it's down to unhappy memories of dressing crabs at catering college. Maybe it's because they don't know what to do with the soft brown meat. Maybe they just can't be fussed to pick it. Or maybe they're just too scared of getting nipped.
None of these excuses holds water. If a chef binned the brown meat, the white would still cost less, gram for gram than lobster meat. And if he did do that, it would be sacrilege, because the brown meat has a unique flavour - try adding it to a shellfish risotto, blended with softened butter, or to a classic bisque, or a seafood sformato (Italian fish stew). The excuse about taking time to prepare is pretty feeble, too. Chefs always seem to find time for an extra garnish or amuse-bouche, whereas cooking and picking a crab is basic prep.
The common edible crab has the advantage of being abundant. It isn't, like cod or wild salmon, in danger of disappearing from our seas. Although there are peaks and troughs in regional supply (the famous Cromer fishery has had a bad year), there's always more than enough fished around the British Isles to meet the national demand.
When Rathmullan House in Donegal won the Moreau Chablis Fish Dish of the Year in 2005, it was for a dish of fresh crab. Head chef Peter Cheesman has moved on, leaving his sous chef, Finn Tommi Tuhkanen, to take over. The hotel has strong ties to the Slow Food movement and is one of only 16 hotels recommended in Ireland's Blue Book.
All about crab: cost, season, basic anatomy, quality, methods of killing, cooking, handling and yield
Prices change according to size, season and sex, but live crab tends to fluctuate between £4.50 and £5.50 per kg, depending on whether it has been bought at source or passed along the wholesale chain. It's a third of the price of UK lobster (£15.50-£22.50 per kg) or less.
Two 500g crabs should yield 180g of white meat and 250g of soft brown meat.
With bought-in prepared fresh crab meat, white meat costs about £3.20 per 100g, soft brown meat £1 per 100g.
May to December, although the hens (females) are in prime condition from August to December. Hens lose their hard shells and breed early in the year.
A little basic anatomy
It's easy to tell a crab's sex. Turn it on to its back and you'll see a kind of "apron", that lifts up (1).
On the male it's more pointed and narrow. On the female it's shaped like a pyramid or dome with hair on the edges. The claws on the male will generally be larger. Half the white meat in the male is found in them.
Inside the carapace, the "brown meat", also called "cream" or "milk" or "curd", is actually a kind of gland, similar to the liver, with the function of digesting food.
The crab's jaws are between the eyes and connect to the stomach.
There are eight gills - commonly called witches' fingers - for breathing on either side of the body.
The edible white meat in the body is separated into compartments, linked to the legs and claws by cartilage.
The female crab's roe, green when raw, turn a bright coral red when cooked.
• Fishermen talk of "hefting" to assess quality. This is easier than it sounds. It simply refers to whether the crab feels heavy in the hand for its size. Generally, this works well, but the shell may contain water that makes it feel heavy.
• The underbelly of a crab in good condition will be creamy coloured rather than white.
• Crabs kept alive for days in viviers may lose condition and weight.
• Stored this way, they may attack each other. To prevent this, some fishmongers cut the tendons in the claws. They then bleed and the juiciness of the claws will be noticeably less.
• Cripples - crabs missing legs or a claw - fetch lower prices. They may offer exceptional value for money.
• Quality and taste. Chefs who are concerned mainly about the quantity of white meat will order cocks, because their claws are larger. Those who wish to use the whole crab, especially the roe, may prefer hens. Anecdotal claims that hens taste better than cocks, or vice versa, don't stand up.
Methods of killing
Chefs nowadays often put crabs in the freezer for a couple of hours and then drop them into boiling salted water or a court bouillon. This is practical and it's easier to judge cooking times.
At North Atlantic Seafood, Alan Davidson recommends lifting the "apron" on the underbelly that covers the central nervous systems (crabs have two) and spiking the crab there with an awl.
Processors drown crabs by leaving them in fresh water for a few hours. In the past, the RSPCA recommended putting live crabs into cold water that was slowly heated to simmering point. Now, for best practice, it recommends two hours in the freezer and then spiking.
Before cooking the crab, it's good practice to turn it on its back and scrub off any muddiness with a brush. This trick, often overlooked by chefs, is essential if they intend using the cooking liquid for a bisque or other soup. Whether it's cooked in water or a court bouillon, the liquid for crab should be well salted, a minimum of 12g salt per litre.
• Drop the crab into the boiling liquid (2).
Ensure that there is at least four times the weight of liquid to shellfish, so that the temperature doesn't drop significantly.
• Cook a crab weighing between 500g and 700g for 18 minutes. Allow an extra two to three minutes for one weighing up to 1200g.
Autotomy: If crabs are dropped alive into boiling water, they have a self-preservation mechanism whereby they can shed legs or even claws. This rarely happens if they have been sedated in the freezer.
• Drain the crab from its cooking liquid.
• Lay it on its back and twist off the two claws from the body (3).
• Twist off the legs (4).
• Hold the carapace with both hands at the back. Press upwards with the thumbs to lever the body out of the carapace (5).
• Pull away the stomach and the gills from the side of the body (6).
• On a hen crab, pull out the visible red coral and reserve (7).
• Split the body. Cut it vertically in half and split each segment into two, following the line where the legs were attached to the body (8).
• Scoop out the white meat from between the cartilage pockets (9).
• Separate each of the claws into their three natural joints (10).
• Crack the large pincers, remove the white meat from the shell and pull out the cartilage.
• Crack each of the other sections and scoop out the white meat.
• Discard the last joints on the legs and separate the other two. Crack them and remove the white meat (11).
• Scoop all the brown meat from the carapace.
White meat (12), about 25% cooked weight, of which all but 5% is in the two claws. Brown meat (curd), 30-35% cooked weight.
White meat, about 20% cooked weight. Brown meat (curd) plus coral (13), 30-35% cooked weight.
Like any other kitchen skill, speed comes with practice. Often chefs order the largest crabs because they know it will probably be quicker to pick a big one than a smaller one and the time per unit will be less. A competent chef will extract the meats from the shell in 10-15 minutes.
Open crab ravioli
(Serves 8 starters)
160g white crab meat
150ml reduced shellfish velouté
60g tomato concassée
1tbs mixed chopped coriander, chives and basil
Salt and pepper
120g brown crab meat
1 hard-boiled egg yolk
1tbs extra virgin olive oil
24 x 7cm ravioli discs
8 pieces of hen crab coral
150ml fish and red wine glaze
30-40 opened cockles or small clams
Combine the white crab meat, velouté and tomato. Season and warm through. Before serving, stir in half the chopped herbs. Blend the brown crab meat, yolk and oil until smooth. Season and add the rest of the herbs. Keep chilled.
Boil the ravioli discs in salted water for two minutes and drain. For each portion, lay three overlapping ravioli discs on the plate. Spoon white meat on each one. Lay a piece of coral against them. Spoon two small mounds or quenelles of brown meat to one side. Splash a little red wine glaze in the gaps between the hot and cold crab. Decorate with clams or cockles in their shells.
Tuhkanen makes his velouté as a cream reduction of shallots, dry white wine, Noilly Pratt, herbs, fish stock and cream. The red wine glaze is a shellfish or fish fumet reduced with port and red wine.
Rathmullan shellfish court bouillon
Prepare a day ahead
2 onions, finely chopped
2 carrots, finely chopped
2 leeks, finely chopped
2 shallots, finely chopped
1 fennel bulb, finely chopped
200ml dry white wine
2 litres water
1 garlic clove, crushed
2 star anise
Cover vegetables with wine and water. Boil. Add crushed garlic, lemon, star anise and bouquet garni. Return to the boil. Simmer 10 minutes. Cool and then strain. Chill, reheat and add 12g salt per litre before use.
Vacuum-Packed Fresh Crab
Chefs who don't have access to a reliable supplier of fresh live crabs might consider precooked, vacuum-packed whole fresh crabs. They have a 28-day shelf life and retain their succulence and some sweetness. The quality is consistent, ideal for crab cakes and similar composite recipes.
In Ireland, there's a large and thriving crab fishery off Malin Head, Co Donegal. For more information on sourcing live and processed crab and crab meat for the UK food service market, contact Grace O'Sullivan of BIM, the Irish Sea Fisheries Board
The Shellfish Association of Great Britain Fishmongers' Hall, London Bridge, London EC4R 9EL. Tel: 020 7283 8305 Dr Peter Hunt, director
For vacuumed-packed crab, contact