Purging Crawfish With or Without Salt: LSU AgCenter Study Finds the Answers
To purge, or not to purge crawfish...that, as they say, is the question. And, if you do purge your crawfish, what's the best way to do it? Purge with salt?
There are a whole lot of questions and opinions when it comes to purging crawfish. Rejoice because the LSU AgCenter might finally have the answers for us.
What's the Best Way to Purge Crawfish?
Apparently, it's all about the crawfish's hindgut, what's in it, and what's the best way to get it out. Many people swear by purging crawfish for a period of time in a saltwater bath while others swear by just keeping the crawfish in regular unsalted water. Yet many people don't even bother purging their crawfish at all and toss 'em in the pot.
The above photo from lsuagcenter.com shows a purged crawfish using the commercial method on the left and an unpurged crawfish on the right.
W. Ray McClain, John J. Sonnier, and Anna McClain with the LSU Agricultural Center have used the good ole scientific method to determine the best purging method to make the crawfish get their hindgut as empty as possible.
From lsuagcenter.com -
Cooks will often empty the entire sack of crawfish into the pot, perhaps after a cursory wash. Others will first empty the sack of live crawfish into a tub of water for a more thorough wash. Many households will routinely add one to two pounds of salt in the wash water with the intent of 'purging' the digestive tract before cooking. This practice is based largely on hearsay or tradition, often passed down from generations.
Here are the four methods of crawfish purging LSU AgCenter used -
1. No washing
2. Crawfish purged in a saltwater bath
3. Crawfish purged in freshwater
4. Crawfish subjected to a commercial purging for 24 hours
Before we go any further, you may be wondering what exactly commercial purging entails.
LSU AgCenter defines a commercial crawfish purging as a water bath lasting anywhere from 12 to 24 hours.
After using all four methods to purge crawfish, they got real scientific to examine the results. "Hindgut content was collected by dissecting the crawfish and flushing the intestine with distilled water over a pre-weighed aluminum pan".
It's also important to note they used farm-raised crawfish for all four purging methods.
So, what did they find out with their crawfish purging study?
The number one overall finding won't surprise you. LSU AgCenter utilizing any of the four purging methods, for even as little as 10 minutes, is going to help with a cleaner boil. In their fancy words, all four of the purging methods "aid in removing mud and debris from the exterior of the animal as evident from the immediate increase in turbidity of the wash water."
Basically, using the water to wash off mud, sticks, crawfish bait, etc. is obviously beneficial. Imagine how dirty the boil water can be if you don't even at least rinse the crawfish with a hose?
The LSU AgCenter reports "10-minute water baths, with or without salt, resulted in from 17 percent to 26 percent less gut content weight than non-washed specimens."
Should You Purge Crawfish With Salt?
Can you handle the answer?
The LSU AgCenter says no, you should not purge your crawfish with salt. They also say yes, you should purge your crawfish with salt.
Their findings actually show the results were so little, that it doesn't seem to matter if you purge with salt or not. The report says "salt provided no significant advantage in this study despite the numerous claims that continue to be made to the contrary."
OK, so the salt purging debate that has divided families and friends for centuries is neither right nor wrong...kind of.
According to the study's findings, the absolute best thing you need to purge your crawfish the best way possible isn't something you can buy.
If you've got the time, you can get a fantastic purge. Time is the number one thing you need for the best crawfish purge possible.
The LSU AgCenter reports "conventional commercial style purging for 12 hours or longer is the only known way to significantly reduce the size of the hindgut in cooked crawfish"
They also note that purging crawfish this long isn't really practical for home boiling.
Oh, let's talk about the salt again. Salt becomes a bad method of purging when you combine it with time. If you purge crawfish in saltwater for any extended period of time, especially 12 to 24 hours, the salt is definitely going to kill them.
The takeaway? Purge your crawfish in regular old water for as long as you can.
Yep, they sure can. Sure, they live in water, but in a situation where you're purging them in an ice chest full of water, they don't have the ability to crawl out of the water for oxygen. According to bluecrayfish.com, crawfish "will drown if they are kept in water that is significantly over their head for 3-6 hours without supplemental oxygenation."
If you're planning on purging your crawfish for an extended period of time, you're going to drain the water every now and then to make sure they don't drown. It takes a crawfish anywhere between 3 to 6 hours to drown without sufficient oxygen. If you're purging crawfish in something you won't be able to drown, so make sure oxygen is getting into the water. Maybe a couple of fish tank air pumps could do the trick if you plan on purging your crawfish for an extended period of time.
Read the LSU AgCenter's full study over lsuagcenter.com.