The Ultimate Guide to Cleaning and Deveining Fresh Crab

October 10, 2024

How to Clean and Prepare Fresh Crab: Species-Specific Guide for Dungeness, King Crab, and Snow Crab

Cleaning and preparing crab is significantly different depending on the species and whether you are working with live/raw crab or pre-cooked frozen crab -- and most guides conflate these two very different situations. Pre-cooked frozen king crab and snow crab legs (which is what most consumers purchase online) require no cleaning at all -- they are fully processed at the processing facility and only need to be reheated. Live or raw Dungeness crab requires the full cleaning process described in this guide. This article covers the complete cleaning process for whole Dungeness crab (the species most commonly purchased live or raw by home cooks), the correct terminology for what you are removing and why, the cracking technique for maximum meat yield, and species-specific notes for king crab and snow crab.

Dungeness Crab Clusters | Dungeness Crab Meat | King Crab | Snow Crab Legs

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Important Distinction: Live/Raw Crab vs. Pre-Cooked Frozen Crab

Pre-Cooked Frozen Crab (King Crab Legs, Snow Crab Clusters, Golden King Crab Legs)

Virtually all commercially sold frozen king crab legs, snow crab clusters, and golden king crab legs are fully cooked and processed at the processing facility before freezing. They require no cleaning -- the gills, digestive tract, and internal organs have already been removed during processing. All you need to do is thaw and reheat. See the Crab Buying Guide for correct reheating times. The cleaning process described in this article does not apply to pre-cooked frozen crab legs.

Live or Raw Whole Crab (Dungeness Crab, Blue Crab, Soft-Shell Crab)

Live or raw whole crab requires the full cleaning process described below. Dungeness crab is the species most commonly purchased live or raw by home cooks in the US (particularly on the West Coast). The cleaning process for whole crab involves removing the carapace (top shell), the gills, and the digestive organs before cooking or after cooking depending on the preparation method.

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Tools Required

• Large pot (for boiling or steaming)
• Kitchen shears (for cutting through shell sections)
• Crab cracker or nutcracker (for legs and claws)
• Seafood pick or small fork (for extracting body meat)
• Large chef's knife or cleaver (for splitting the body)
• Cutting board
• Large bowl of ice water (for stopping the cooking after boiling)
• Running cold water (for rinsing)

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Cleaning Whole Dungeness Crab: Step-by-Step

Step 1: Cook the Crab

Boiling (most common): bring a large pot of heavily salted water to a rolling boil (use approximately 1/4 cup of salt per gallon of water -- the water should taste like seawater); submerge the live crab; return to a boil; cook for 15-18 minutes for a 2-lb crab (add approximately 2 minutes per additional pound); the shell will turn bright red-orange and the meat will be opaque and firm when done.

Steaming: fill a large pot with 2-3 inches of water; bring to a boil; place the crab on a steaming rack above the water; cover tightly; steam for 18-22 minutes for a 2-lb crab; steaming produces slightly more flavorful meat than boiling because the crab's natural juices are not diluted by the cooking water.

Transfer the cooked crab immediately to a large bowl of ice water for 2-3 minutes to stop the cooking; remove and let drain.

Step 2: Remove the Carapace (Top Shell)

Turn the crab belly-side up; locate the apron (the triangular or T-shaped flap on the underside -- triangular in males, wider and rounder in females); lift and pull back the apron; use your thumbs to grip the edge of the carapace (top shell) and pull it away from the body; it should come off cleanly in one piece. Set the carapace aside -- it can be used as a serving vessel or for stock.

Step 3: Remove the Gills ("Dead Man's Fingers")

The gills are the soft, feathery, grey-white structures arranged in two rows along the sides of the body cavity -- they are called "dead man's fingers" due to their appearance. The gills are not toxic but are unpleasant to eat (spongy, flavorless, and slightly bitter). Remove all of the gills by pulling them away from the body with your fingers; discard them.

Step 4: The "Crab Mustard" -- Remove or Keep?

The yellow-green substance in the body cavity is the hepatopancreas (the crab's liver and pancreas combined), commonly called "crab mustard" or "tomalley." It is not the digestive tract and is not a contaminant -- it is edible and is considered a delicacy by many crab enthusiasts; it has a rich, intensely flavored, slightly bitter taste. Some people eat it directly from the shell; others mix it into sauces or butter. However, the hepatopancreas can accumulate environmental contaminants (heavy metals, domoic acid during harmful algal bloom events) at higher concentrations than the muscle meat -- if you are in an area with active shellfish safety advisories, discard the hepatopancreas. In the absence of a specific advisory, it is safe to eat in moderate amounts.

Step 5: Rinse the Body

Hold the cleaned crab body under cold running water and rinse out any remaining debris, sand, or loose material from the body cavity; use your fingers to clear the chambers; pat dry.

Step 6: Split the Body

Place the cleaned body on a cutting board; use a large chef's knife or cleaver to cut the body in half down the center; this exposes the body meat chambers and makes it easier to extract the meat. The body meat of Dungeness crab is significant -- do not discard it; it is the same quality as the leg meat and represents approximately 30-40% of the total edible meat in a whole Dungeness crab.

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Cracking Technique: Maximum Meat Yield

Legs

Use kitchen shears to cut along the length of each leg section (cut along one side of the shell, not through the middle -- cutting through the middle crushes the meat); open the shell like a book; the meat should come out in one piece. Alternatively, use a crab cracker to crack the shell at the joints and pull the meat out with a seafood pick. The goal is to crack the shell without shattering it into fragments that embed in the meat.

Claws

The claw has a movable finger and a fixed finger; crack the shell at the widest point of the claw (not at the tip) using a crab cracker or the back of a heavy knife; apply firm, controlled pressure -- too much pressure shatters the shell and drives fragments into the meat; too little pressure requires multiple attempts that also fragment the shell. Once cracked, pull the two halves apart; the meat should come out largely intact. Use a seafood pick to extract any meat remaining in the claw tip.

Body Chambers

The body meat is in small chambers separated by thin cartilage walls; use a seafood pick or small fork to extract the meat from each chamber; work systematically from one side to the other; the body meat is worth the effort -- it is identical in flavor to the leg meat and is often overlooked by home cooks who focus only on the legs and claws.

Saving the Shells for Stock

Crab shells (carapace, leg shells, claw shells) make an excellent seafood stock base. Rinse the shells; roast at 400°F (200°C) for 15-20 minutes until lightly browned (roasting deepens the flavor); simmer with onion, celery, carrot, garlic, bay leaf, and peppercorns in water for 45-60 minutes; strain. The resulting stock is the base for bisque, cioppino, and seafood pasta sauces.

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Species-Specific Notes

King Crab and Golden King Crab (Pre-Cooked Frozen Legs)

Pre-cooked frozen king crab and golden king crab legs require no cleaning. Thaw overnight in the refrigerator; reheat by steaming (5-7 minutes thawed), boiling (3-5 minutes thawed), or grilling (4-5 minutes per side, thawed only). To extract the meat: use kitchen shears to cut along the length of the leg; open the shell; the meat comes out in one large piece. King crab leg meat is the largest and most impressive of the commercial species -- a single leg section can yield 3-6 oz of meat. There is no body meat in pre-cooked king crab legs (the body is removed during processing).

Snow Crab (Pre-Cooked Frozen Clusters)

Pre-cooked frozen snow crab clusters require no cleaning. Thaw and reheat as above. Snow crab legs are thinner than king crab legs and the shell is easier to crack by hand -- grip the leg at a joint and bend sharply to crack the shell; the meat slides out. Kitchen shears work well for the larger sections. Snow crab clusters include a section of the body with the legs still attached -- the body section contains a small amount of additional meat that can be extracted with a seafood pick.

Dungeness Crab (Whole, Live or Pre-Cooked)

Follow the full cleaning process above. Dungeness crab has the most complex cleaning process of the three species but also the most rewarding body meat yield -- approximately 30-40% of the total edible meat is in the body. Dungeness Crab Meat (pre-picked) and Dungeness Merus Crab Meat (premium grade, leg section meat extracted intact) are available pre-cleaned and pre-picked for convenience.

Dungeness Crab Clusters | Dungeness Crab Meat | King Crab | Snow Crab Legs

Also see: How to Buy Crab Online: The Complete Buyer's Guide | King Crab Dipping Sauce Recipes

Watch seafood preparation videos on the Global Seafoods YouTube Channel

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Frequently Asked Questions About Cleaning and Preparing Crab

Do I need to clean pre-cooked frozen king crab or snow crab legs?

No -- pre-cooked frozen king crab legs, golden king crab legs, and snow crab clusters are fully processed at the processing facility before freezing; the gills, digestive organs, and internal matter have already been removed. They require no cleaning -- only thawing and reheating. The full cleaning process described in this article applies to live or raw whole crab (primarily Dungeness crab purchased live from a fish market or tank).

What is "crab mustard" and is it safe to eat?

"Crab mustard" (or tomalley) is the hepatopancreas -- the crab's liver and pancreas combined. It is the yellow-green substance found in the body cavity when you open a whole crab. It is edible and is considered a delicacy by many crab enthusiasts -- it has a rich, intensely flavored, slightly bitter taste. However, the hepatopancreas can accumulate environmental contaminants at higher concentrations than the muscle meat. In the absence of a specific shellfish safety advisory for your area, it is safe to eat in moderate amounts. During active harmful algal bloom events (domoic acid advisories, which occur periodically in California), discard the hepatopancreas.

What are the "dead man's fingers" and do I have to remove them?

"Dead man's fingers" are the gills -- the soft, feathery, grey-white structures arranged in two rows along the sides of the body cavity. They are not toxic but are unpleasant to eat (spongy, flavorless, and slightly bitter). Always remove and discard the gills before eating or serving whole crab. They are easy to pull away from the body with your fingers after the carapace has been removed.

How do I get the most meat out of a whole Dungeness crab?

Three tips: (1) do not neglect the body meat -- approximately 30-40% of the total edible meat in a whole Dungeness crab is in the body chambers, not the legs and claws; use a seafood pick to extract it systematically; (2) use kitchen shears to cut along the length of leg sections rather than cracking with a cracker -- cutting produces cleaner meat with fewer shell fragments; (3) crack claws at the widest point (not the tip) with firm, controlled pressure -- shattering the shell drives fragments into the meat and makes extraction difficult.

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