Many American regional dishes usually have more than one school of thought behind them... such as the ever controversial BBQ. To a lesser level, the Louisiana crawfish boil is another (because most people will only ever come in contact with the New Orleans version). I am not referring to the subtle differences between one cook and the next, but the larger aspects that differentiate bayou Cajun crawfish from the New Orleans city boil. On a larger level, this controversy extends to Cajun food itself. The first adjective that is typically uttered after the word Cajun is 'spicy.' Nothing could be further from the truth. Think about hot spicy 'cajun' food, and the only place you will see that is in New Orleans. Blackened fish... New Orleans. Gumbo pots with everything but the kitchen sink in them... New Orleans. I've seen many of my local dishes bastardized in almost every New Orleans kitchen I've worked in. Crawfish is at the top of that list. In the city, people boil them in pots filled to the top with water so spicy they keep most noses at bay from the fumes and the overuse of spices raises the question that one may as well be cooking shoe soles. The original flavor of the crawfish is not coaxed out... but dragged out, beaten to death, and buried in cayenne.
Now it may seem dated to even post on cajun food. In my lifetime, the trend has been abused to the point that you can find a 'cajun' item on every menu across the US. 'Cajun Chicken Sandwich'... what in the hell is that anyway? The perception is that you can rename everything with the 'cajun' adjective just by sprinkling cajun seasoning on it... sometimes even after cooking. In that respect, I offer no apologies to Chinese and Italian Americans who lament that the American versions of their base cuisines resemble no likeness to their original dishes. However, I feel your pain probably moreso.
On the upside... with crawfish, I do respect both city-fied and country versions. I was 'born on the bayou,' but did live in New Orleans for quite some time. The bayou school of cooking is much more deeply embedded within my soul. No matter where I go, or how much I learn, or how many different hydrocolloids I can gel carrot juice with... I cannot escape it. Gumbo juice is my mother's milk.
Lets walk through the cajun crawfish method. The first misconception is the word 'boil' (on the bayou pronounced 'bawl,' and in New Orleans pronounced 'berl). Although they may actually boil in New Orleans, on the bayou the amount of water in the pot is kept very low... thus, creating more of a uniform atmosphere of flavored steam within the closed pot (yes, you cannot properly do this without a lid). When you ponder it, it really makes no sense to start with so much water when the shellfish will give off their own liquids during the cooking... you always get more than what you started with.
First, clean those suckers. They're not called 'mudbugs' for nothing. They live in the mud. If you've never seen a crawfish hole, it's a hole in the ground with an elevated 'levee' of mud packed all around it.
How do you clean them... just put them in a tub (we use a number 3 tub), and fill it with tap water until the crawfish are submerged. We used to pour a box of salt into the water with the belief that it caused the crawfish to 'spit up' whatever mud was inside, but this has been scientifically proven untrue. Just a few minutes in clean water to rinse the outsides is enough. Drain them off afterward.
With about 8 to 10 inches of water in a large stockpot (for a 35# sack), bring it to a boil. At this point, there should be nothing else added to the water. Once a boil is reached, drop in your potatoes. Traditional accompaniments in the boil are red bliss potatoes and corn on the cob. Let the potatoes cook for about 15 minutes depending on the size. Afterwards, add in 1 box of salt and drop in the whole onion, garlic, lemon, celery, (mushrooms if you want them), bell peppers, and wait for steam. With the lid on, once you see steam time it out for another 8 minutes. My uncle Chunky picks his bell pepper and lemon at peak season and freezes them for crawfish and crab season. I believe that this freezing also breaks down the cell walls of the plants and allows for their preserved flavor to more easily dissolve into the water. Chunky also uses 'lingerie nets' with zippers to hold the potato and corn. By doing this, they can be plucked easily from the water and re-added on top of the crawfish... keeping them from getting crushed under the weight.
Now, add in the crawfish. A large pot usually holds anywhere from 30 to 40 pounds. Pour about 2 1/2 cups of liquid Zatarains crab boil, dump the crawfish, and pour another box of salt over them. Put the lid securely back on. Chunky used to use a DIY contraption that was essentially a bar with a valve screw attached. This was used to lock the lid on creating a pressure-cooker effect. It works fine without it.
Once the crawfish are covered in the pot, wait until steam is visibly wafting from under the lid. Time out 8 minutes from this point. Begin to check for doneness by scooping out 1 or 2 crawfish and tossing them into some cool water. The flavors must be present but will not be strong at this point. You are essentially checking the texture for doneness.
Chunky, sometimes being a one-man show, devised a pulley mechanism for lifting the basket out of the pot. There is, however, a very important step which must be carried out before this. Once the crawfish are ready, open the lid and use a hose to fill the water level up to the top of the crawfish. The pulley system makes it easy to raise and lower the basket a few times in a dunking effect. This is very important. The tap water drops the temperature of the water a bit (but not too much). The cooler water forces the flavors into the crawfish. After a few dunks, let the crawfish sit in the water for no more than 5 minutes. Raise them out and drain. Without any culinary school training, my uncles had all discovered this 'method' years ago to 'force' the flavor quickly into the crawfish. I still use it to this day to cook shrimp for cocktail (throwing the shrimp and their cooking liquid into a bucket and dropping ice directly on top). Harold McGee meets Justin Wilson. As foods cool, they absorb whatever liquid is in contact with them (like bacon that's not removed immediately from its rendered fat making very greasy bacon).
Raise the crawfish out of the pot for a minute and let them drain, then eat. We typically make a sauce for crawfish and crab that consists of mayonnaise and ketchup mixed with a variety of other ingredients. It's funny that once moving to South Florida, I've discovered that Argentinians and other South Americans make a very very similar sauce called 'salsa golf.' On the bayou, we simply call it 'dip,' and anyone will know exactly what you are talking about when you ask for it. Make sure you have ample old newspapers saved up to line your tables.
On a side note, cooking crabs is done the exact same way... except that you will start with a little over half the water you would start with for crawfish. Also, because they are bigger in size, time out 12 minutes after seeing steam before tasting.
As a side note... Chunky saved all of the shells afterward to bury for compost in his garden. After tasting the field peas (similar to a crowder pea) and cucumbers growing there, I can't argue with the idea. This is what real cajun food is all about. How mislead the rest of America was all this time about our cuisine. Also when examining the difference in approach between cajun country and New Orleans city cooking, it makes sense that people on the bayou, who are much more closer to the origins of their food, would respect it just a little more and cook in a way that brings out that flavor instead of covering it up.