Cooking guide
How Long to Cook Crabs
Crab is one of the most rewarding shellfish to cook at home. The process is simple — heavily salted boiling water, live crabs plunged in head-first, and patience while the shell turns its stunning bright red. The key variables are weight and liveness: a small live crab needs barely ten minutes; a large one over a kilogram can take more than twenty. Pre-cooked frozen crabs are a different matter altogether and only need two or three minutes to heat through.
- Stun in freezer first
- Heavily salt the water
- Shell turns bright red when done
Quick answer
Quick Answer
Heat through only
From boil return
From boil return
From boil return
Flesh white and opaque
~30 g salt per litre
Calculator
Crabs Cooking Time Calculator
Select the state and size of your crab for an estimated cooking time.
Cooking temperature: heavily salted rolling boil. Start timing once the water returns to a full boil after adding the crab.
These estimates assume a live crab stunned in the freezer and plunged head-first into boiling water.
Preparation
How to Prepare Crabs Before Cooking
Live crabs must be handled humanely and safely. Place them in the freezer for 15 minutes before cooking — this renders them inactive without killing them, making them safer to handle. Do not leave them in ice water, which does not stun effectively. Rinse the crab thoroughly under cold running water to clean the shell. If using frozen pre-cooked crabs, thaw in the refrigerator overnight or under cold running water before reheating.
For the cooking water, seasoning matters greatly. Use a large pot of heavily salted water — around 30 g of salt per litre, similar to seawater. Add aromatics: bay leaves, black peppercorns, a halved lemon squeezed into the water, and thyme. Some cooks add wine. These aromatics perfume the meat as it cooks.
Method
How to Cook Crabs Step by Step
- Place live crabs in the freezer for 15 minutes to stun them. Rinse under cold water.
- Fill a large pot with water. Add salt (30 g per litre), bay leaves, peppercorns, halved lemon, and thyme.
- Bring to a vigorous rolling boil over high heat.
- Grip the stunned crab from behind and plunge it head-first into the boiling water.
- Cover the pot and wait for the water to return to a full boil. Start timing from that point.
- Cook small crabs 10 to 12 minutes, medium 12 to 18 minutes, large 18 to 25 minutes.
- For frozen pre-cooked crabs, cook 2 to 3 minutes just to heat through.
- Remove and rest for 5 minutes before serving or cracking.
Cooking chart
Crabs Cooking Time Chart
| State | Size | Time | Notes |
|---|---|---|---|
| Frozen (pre-cooked) | Any | 2 to 3 minutes | Heat through only; already cooked. |
| Live | Small (under 500 g) | 10 to 12 minutes | From the moment the water returns to a boil. |
| Live | Medium (500 g–1 kg) | 12 to 18 minutes | From the moment the water returns to a boil. |
| Live | Large (over 1 kg) | 18 to 25 minutes | From the moment the water returns to a boil. |
Doneness
How to Know When Crabs Are Done
A properly cooked crab has a uniformly bright red shell with no grey, blue, or green patches remaining. Pull off a claw and crack it — the flesh inside should be white and fully opaque, with no translucent or jelly-like areas. The shell also separates more easily from the body when the crab is fully cooked. If in doubt, add 2 more minutes and check again.
Safety note: crab must be cooked through completely. Undercooked crab can harbour harmful bacteria. The internal flesh must be uniformly white and opaque before serving.
Seasoning
Best Seasonings for Crabs
The cooking water does much of the seasoning work. Heavy salting (like seawater), lemon, bay leaf, black peppercorns, and thyme are the classic aromatics. After cooking, crab pairs beautifully with melted garlic butter, homemade mayonnaise, or a simple vinaigrette. For a spiced approach, Old Bay seasoning (a classic American choice) adds paprika, celery salt, and mustard notes. The sweet, delicate meat of the claws is best with minimal interference — a squeeze of lemon and good bread are often enough.
Avoid this
Common Mistakes
- Starting in cold water — always plunge live crabs into boiling water for better texture and humane killing.
- Underseasoning the water — crab needs heavily salted water or the meat will taste bland.
- Overcooking — overcooked crab meat becomes dry and fibrous; use the time chart and check early.
- Not resting the crab — a 5-minute rest before cracking allows the meat to firm up slightly, making it easier to extract.
- Skipping the freezer step with live crabs — this is both for safety and humane reasons.
Serving
What to Serve With Cooked Crabs
Whole boiled crab is a celebration dish — serve at the table with claw crackers, picks, and plenty of napkins. Melted garlic butter and lemon wedges are the classic accompaniment; homemade mayonnaise or aioli works just as well. For a more elaborate presentation, dress the picked meat with herbs, capers, and a splash of white wine vinegar, then pile it back into the shell. Crab also makes an excellent addition to salads, chowders, pasta, and crab cakes.
Recipe ideas
Crabs Recipe Ideas
- Dressed crabPick brown and white meat separately, mix each with seasoning, and serve in the shell with toast and lemon.
- Crab with garlic butterHalved boiled crab finished in foaming butter with garlic, parsley, and a splash of white wine.
- Crab bisqueUse shells to make a rich stock, blend with cream and cognac for a classic bisque.
- Crab cakesMix picked white meat with breadcrumbs, egg, mustard, and herbs; pan-fry until golden.
Leftovers
Storing and Reheating Cooked Crabs
Cooked whole crab keeps refrigerated for up to 2 days. Picked crab meat should be used within 1 day. Reheat gently in butter in a pan rather than boiling again. Freeze picked crab meat for up to 2 months; use in soups, cakes, or pasta rather than serving plain, as texture softens after freezing.
Tools
Useful Tools for Cooking Crabs
- Large stockpotMust be big enough for the crab to be fully submerged in boiling water.
- Tongs or spider strainerFor safely lowering and lifting hot crabs from boiling water.
- Claw crackersFor breaking the claws to extract the white meat cleanly.
- Crab pickA thin metal pick for pulling meat from smaller cavities in the legs and body.
Questions
FAQ
How long do crabs take to cook?
Live crabs cook in 10 to 25 minutes depending on size. Small crabs under 500 g take 10 to 12 minutes; medium 500 g to 1 kg take 12 to 18 minutes; large over 1 kg take 18 to 25 minutes. Time from the moment the water returns to a full boil after adding the crab. Pre-cooked frozen crabs only need 2 to 3 minutes to heat through.
Should you put crabs in boiling or cold water?
Always plunge live crabs into already-boiling water. Starting in cold water causes the crab to shed claws, stresses the animal for longer, and results in inferior meat texture. Use heavily salted boiling water and plunge the crab in head-first for the quickest, most humane cooking.
How do you know when a crab is fully cooked?
A fully cooked crab has a uniformly bright red shell with no grey or blue areas. Crack a claw — the flesh should be completely white and opaque with no translucency. Overcooked crab meat becomes dry and rubbery, so check at the lower end of the time range and add minutes only if needed.
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