The Common Marinade Mistake That Leads To Chewy Shrimp

Steak and poultry marinades usually contain an acid component (like citrus juice or vinegar), a fat component (like oil or dairy), salt, other seasonings, and sometimes even something sweet to balance it all out. The acid helps tenderize the meat, and the fat aids with the distribution of fat-soluble flavors into the meat while helping to retain moisture. However, marinate your meat for too long and the acid is in danger of breaking down the proteins too much so they become mushy or stringy.

But this all works a little differently with shrimp, where you need to be even more careful with an acidic marinade. While an acid-heavy marinade will still break down the proteins in shrimp, it creates the opposite result, texture-wise. Rima Kleiner, a registered dietitian and blogger, touched on this dynamic when explaining to Mashed why shrimp tastes better at a restaurant: "Acid breaks down the proteins in shrimp, which can make the shrimp tougher if in vinegar or citrus juice for too long."

Acids create a chemical reaction in proteins called denaturation — basically meaning that it changes the shape of the protein compound. In shrimp this means the protein bonds tighten, water is expelled, and the shrimp's exterior becomes tough and chewy, even more so when placed under (or above) heat.

When shrimp is denatured in citrus juice or vinegar, it is, essentially, "cooked" without using any heat. That's how shrimp ceviche is made, after all, and there's nothing wrong with that. However, to avoid unwanted chewiness, Rima Kleiner recommended limiting the marinade time to half an hour or less in the fridge. This will ensure that the acid doesn't penetrate the proteins too thoroughly, still leaving plenty of moisture for cooking.

If you'd rather skip that step, you can certainly cook your shrimp with no acid whatsoever, using just olive oil, herbs, and a good bit of salt to help the flavor penetrate. That said, shrimp recipes can lack oomph without a decent dose of citrus. Some swear by a dry brine "pre-marinade" of salt and baking soda to retain moisture and keep the shrimp nice and crispy. But the easiest way to get the desired flavor may be to forgo the marinade altogether and just cook the shrimp in citrus directly. You can create a sauté sauce with lemon juice, orange juice, garlic, and onion, then add your raw shrimp once the sauce has cooked down a bit. This way you'll get all the beautiful citrus flavor, without tempting denaturation, before the shrimp has hit the heat.

Similarly, you can add a couple tablespoons of citrus juice as the shrimp is cooking or simply give it a good squeeze of lemon right after it goes on the plate. Just remember: When using citrus with your shrimp, don't let it soak too long or you might as well make a ceviche.