How to Purge Crawfish

Co-authored by Dorrenda Smith

Last Updated: December 21, 2022 References Approved

Crawfish, sometimes called crayfish, are similar to lobsters but much smaller. As they make their home in the mud of freshwater bayous, they are often referred to as "mud bugs." Crawfish are most commonly found in Louisiana, and they are eaten there as a part of southern cuisine, or Cajun cooking. Crawfish are tender and have a salty-sweet mineral flavor, similar to crab. They usually boiled but they need to be cleaned first, which is referred to as purging. Purging helps rid the crayfish of impurities in their intestinal tract, such as mud and grass, to make them more palatable.

Method 1

Method 1 of 3:

Prepping Crawfish Before Cleaning

1
Keep the crawfish in the sack they arrive in if you are not going to cook them right away. Crawfish will die if stored in water for too long, so leave them in the air.
2
To store them for longer, briefly hose them down with water and place them in a container with ice. Live crawfish can be kept at 36ºF to 46ºF for a few days. Drain them as needed, so you aren't leaving them submerged in water.^{[1]
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- Be sure to remove the ice and let the crawfish return to room temperature before purging and cooking.
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3
Take the live crawfish out of the sack and put them into a large plastic tub or cooler. Make sure your container has enough room to thoroughly clean them. Also make sure they won't be able to somehow crawl out.

Method 2

Method 2 of 3:

Purging with Salt

1
Pour salt over the crawfish in the tub. Take your salt box or grinder and shake it liberally over them. Regular table salt will do—this isn't intended for seasoning. The bugs should go wild with discomfort when you do this.
- Salting is optional. Some cooks believe that salting may help clean the crawfish better by compelling them to essentially vomit and purge any mud and waste in their digestive system. However it also increases the risk of killing the crawfish during the purge.
2
Use large instrument to stir them up and then salt them again. You want to try to salt the whole batch evenly.
3
Pour fresh water over the live crawfish until they are just submerged. You can use another bucket or just fill their tub up with a hose. When this happens, the crawfish spit out the grime in their system, minimizing fishy taste and odors and reducing the size of their gritty sand vein.
4
Stir gently with a large instrument for about 3 minutes. The moving water will help wash the mud off the crawfish's shells and gills.
5
Pour out the salt water, keeping your crawfish in their tub. Try to drain the salt water completely.
6
Refill the tub with new fresh water, and stir. Check for any dead crawfish that float to the top—remove them and throw them away immediately.
7
Rinse them one more time. After giving it a stir, the water should be much less grimy than in previous rinses. If you are satisfied with the cleanliness, you are done purging.
8
Drain the water and proceed to boil your crawfish.

Method 3

Method 3 of 3:

Purging Without Salt

1
If you choose not to use salt, simply fill up the tub with water and let the crawfish sit in the water for 5 to 10 minutes. You can give them an occasional stir to help loose dirt and grime.
2
Pour out the grimy water and refill the tub with new fresh water. Let the live crawfish sit for another 5 to 10 minutes.
3
Check for dead crawfish floating on the top and remove them immediately. Crawfish are best if you boil them live.^{[2]
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4
Drain the container again and fill it one more time. Give them a last stir and check the muddiness of the water. It should be reasonably clear now.
5
Drain the water and boil your mud bugs!

Expert Q&A

Question

How should crawfish look when cooked?

Dorrenda Smith
Personal Chef
Dorrenda “Renny” Smith is a Personal Chef and the Co-Founder & CEO of The Crain Experience. With almost 15 years of experience in the food industry, she specializes in creating soul food with a healthier spin. Chef Renny and her partner provide event catering, event planning, and restaurant and food truck consultations.

Dorrenda Smith

Personal Chef

Expert Answer

The crawfish will turn a very bright vibrant red color. At that point, you will see the tails curled up and they're done—it usually takes five minutes for them to actually be cooked. But in order to absorb the flavor they have to sit for at least 30 to 45 minutes.
Question

The song says, "struped and cleaned before your eyes." Is "struped" another word for purging?

Community Answer

Thy lyric is actually "stripped and cleaned." Never heard purging called anything but purging.
Question

What is the cooking time for crawfish?

Community Answer

Boil the crawfish for 15 minutes. Then turn the heat off and allow the crawfish to simmer in the liquid for an additional 15 minutes.

Warnings

Purge crawfish right before boiling; if you do it any earlier, they will die.

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Crawfish need air to stay alive; do not let them sit in water for too long.

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Do not eat crawfish that have died before cooking; they will not taste good.

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Some cooks argue that adding salt does nothing to make purging more effective, but it is traditional in many methods.^{[3]
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