What does it mean to devein a shrimp? How is this done?--Zack
Along the back of a shrimp, on the outside curve, there is a black line running from head to tail. To some people the term deveining may be confusing, as this line is actually the intestinal tract of the shrimp and not a vein at all. On larger shrimp (or prawns) this tract may have bits of grit that are unpleasant to bite down on. For this reason, the digestive tract is usually removed. On small or medium shrimp, there is less chance of grit, but some people like to remove the vein for aesthetic reasons.
While there are any number of gadgets from plastic hooks to electric processors available to the home cook, unless you are doing hundreds of shrimp all you really need are your hands, a sharp paring knife and a large bowl of ice cold water. If the shrimp have their heads on, the first step is to twist them off. Set those aside for future use, or discard them. Heads and shells can be used to make a stock for dishes such as shrimp bisque.
Now take the shrimp, one at a time, and peel the shells off. To do that, hold the shrimp in one hand, and with the fingers of the other hand pry the shell away from the belly and peel around to the other side. The shell has a space just near the legs to make this easy. If you want tail on shrimp, leave the tail and the last ring of shell before it in place. Sometimes some of the legs will remain behind, so pull those off.
Next, hold the shrimp in one hand, and with the other hand use the paring knife to follow along the back right over top of the digestive tract from head to tail. It will take a little practice to learn how deep you need to cut, but once the tract is exposed, you can use the edge of the knife blade to scrape out the tract. Rinse the shrimp in the cold water to remove any last traces. I also always swish the knife in the water to take off any bits that may have stuck to it, too.
If you are butterflying the shrimp for the dish you are making, go back and deepen the same cut until it goes about three quarters of the way through the flesh, them spread the shrimp out so that it lies flat. Some recipes may also suggest lightly pressing or pounding the flesh to get lie even flatter.
This process is really quick and a few dozen shrimp can be done in no time.