Everything You Need to Know to Buy Better Shrimp

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[Photograph: Vicky Wasik]

Shrimp has been the most popular seafood in the US for years—it represents more than a quarter of the seafood eaten in this country. It's also one of the most varied categories: You can find dozens of different species of shrimp, each boasting multiple names and preparations. You can buy them with the head on or off, the shell on or off, the vein removed or intact, tail-on or tailless. Some are available pre-cooked; others are frozen, fresh, or previously frozen. Then there's the matter of shrimp vs. prawns, just to further muddy up the waters (and many species of shrimp, for what it's worth, prefer muddy waters).

For such a beloved ingredient, shrimp can be fantastically confusing, and what information we do get on labels doesn't offer much help when it comes to shopping for the best shrimp. You'd be very much forgiven for wondering just what the difference is between the dozens of possible permutations. And there are some serious sustainability issues at work, as well—your seafood aisle selection can have a real impact on local economies and entire marine environments.

So here is a deep dive into what all this shrimp talk really means, with tips on how to help you figure out exactly what shrimp to buy.

The Quick Version

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We recommend buying individually frozen (IQF), head-off, peel-on shrimp for most preparations. If you're looking for sustainably farmed or fished shrimp, go for freshwater varieties or seek out labels of approval from independent groups like Marine Stewardship Council, Aquaculture Stewardship Council, and Naturland.

Shopping for Shrimp

Pick Your Size

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A shrimp's size is measured by the number of individual shrimp it takes to make up a pound. A label of 16/20 means that there are between 16 and 20 of these shrimp in a pound. Sometimes you'll see a letter U as well, like U10, which means fewer than 10 of those shrimp make up a pound.

The main takeaway? The smaller the number, the bigger the shrimp. While labels like "medium" or "jumbo" aren't regulated and thus can vary greatly from seller to seller, here's a general guide when picking shrimp for a recipe that doesn't specify shrimp size by count number:

Shrimp Sizing Chart

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Shrimp Label Shrimp Per Pound
Small 51 or greater
Medium 36 to 50
Large 26 to 40
Jumbo 16 to 25
Colossal Fewer than 15

Check for Freshness

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Shrimp are highly perishable, so it's important to know how to pick out the freshest shrimp available, not just for taste and texture but also for safety. First off, you don't want any shrimp that smell like ammonia—this is a telltale sign of spoilage, and it's worth asking your fishmonger if you can take a sniff before buying. You'll also want to avoid shrimp that are limp, slimy, or falling apart, all of which are signs of decay.

A more advanced sign if you're buying head-on fresh shrimp: look for black spots on the head first, then the body. "That's a pretty good indicator that it's not at peak freshness," says Davis Herron, the retail director at The Lobster Place, one of New York's best seafood markets. The black spots are called melanosis; it's the result of the same oxidation process that turns your apples and avocados brown. In other words, they don't definitively mean that your shrimp is bad, but they do indicate that the shrimp could be fresher.

In most cases, you're better off buying frozen shrimp, even when "fresh" shrimp are available. Read on to see why.

Frozen or Fresh

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The vast majority of shrimp sold in the supermarket or at the fishmonger were deep frozen at sea and delivered to the retailer in that state. That display of "fresh" shrimp you see at the counter? Those are the same bags of frozen shrimp you find in the freezer that have simply been allowed to thaw out in the store before going on display. There's no way to know how long they've been there defrosted, so you're better off buying the frozen shrimp and defrosting them yourself at home where you have more control over the process and can guarantee that your shrimp don't spend too long out of the freezer before being cooked.

The one exception to the always-buy-frozen rule is when you have access to live shrimp, either fresh from the ocean, or stored in tanks at the shop. In those cases, cook the shrimp as soon as possible after purchasing for best flavor and texture.

Block or IQF?

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Shrimp tend to be frozen either in large five pound blocks or by using the IQF (Individually Quick Frozen) method. We recommend opting for the second. IQF shrimp tend to show less damage during freezing. They also make it easy to thaw only the shrimp you need for a single meal at a time.

If you're buying from a grocery store freezer, take a peek in the little transparent plastic window at the shrimp within. Any freezer burn? Move on to the next bag. Freezer burn indicates that the shrimp have either partially thawed before being refrozen, or have been poorly handled during their freeze, both of which are bad for texture and flavor.

How to Thaw Frozen Shrimp

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Frozen shrimp should always be thawed before cooking. To thaw frozen shrimp take them out of their bag and place them in a bowl under cold (not warm) running water. They'll be good to go in just a few minutes. If you don't want to let the water run, place them in a bowl of cold water and let them rest until defrosted (it'll take about twice as long using this method). For most recipes, it's a good idea to thoroughly dry your shrimp on paper towels before proceeding.

Heads and Shells

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For super-fresh or live shrimp, "I like the head on because it gives you a few more options," says Herron. "A lot of people will grill them head-on, then take the heads off, and there's this great sort of bitter juice that comes out of the head once it's been cooked—it's not for everybody, but it's great in stocks and sauces." We even like the heads all fried up.

That said, shrimp heads can also have negative effects on quality. As Kenji notes, "Shrimp heads contain powerful enzymes that start to break down shrimp flesh as soon as they die. Within hours, head-on shrimp will become noticeably mushier. Headless shrimp, on the other hand, have their heads removed before shipping, which means that their bodies retain their fresh, briny crunch. Unless you can get your shrimp live (a possibility if you live near a good Asian market), you're better off going with the headless version."

Assuming you're buying headless shrimp, you're encountering either shell-on, EZ-peel, or entirely peeled shrimp.

  • Shell-on shrimp are what we recommend. Shelled shrimp are often mangled and unappetizing. Shell-on shrimp also tend to be much cheaper. Finally, those shells pack a sweet, flavorful punch, whether you grill the shrimp directly in the shell, or use the shells to add flavor to the final dish like in this Spanish-style shrimp.
  • EZ-peel shrimp are already split and deveined—you'll be able to hold onto those flavorful shells and they'll make your job that much easier. That said, they come with a price bump and a little less control over your final product—the machines used to split and devein the shrimp tend to create a deeper gouge than you'd make working carefully at home. If you're making something where the shrimp's appearance doesn't matter—dumplings, for instance—go for it. But if you want a good looking array for something like shrimp cocktail, you'll probably want to peel 'em yourself. In either case, be sure to hold onto your shells: they can be simmered with aromatics to make a flavorful seafood stock, sauce, or oil.
  • Pre-peeled shrimp are at the top of the ladder in terms of ease of preparation, but also in price. Moreover, they tend to be overhandled and mangled, making them unsuitable for most recipes. We don't recommend buying them.

To Devein or Not to Devein

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The "vein" of a shrimp is actually its digestive tract, typically a thin, dark tube of, well, shrimp poop. It's not necessarily risky to eat it, but it's also not something we'd recommend, as it could contain sand (which has an unpleasant texture) or could taste bitter, and it's easy enough to get rid of it. There are a few methods to devein a shrimp. The first and easiest is to just ask your fishmonger to do it. No tools are required for this method.

But it's pretty easy to do it yourself, as well. You can, with a paring knife, make a shallow incision right through the shell on the shrimp's back, from its head to its tail, and then pick out the vein. Or you can do what Herron recommends and grab a shrimp deveiner, a curved plastic tool that costs fewer than five dollars on Amazon and will both peel and devein for you in the blink of an eye.

On Pre-Cooked Shrimp

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Just don't. "Pre-cooked" shrimp should almost universally be labeled "overcooked" shrimp. They're usually rubbery and bland, and since they're already cooked, offer no room for flavor improvement and will end up dry when added to dishes. Leave them be.

Additives

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Shrimp are occasionally treated with chemical additives designed to increase their thawed shelf life or to get them to suck up and retain excess moisture so that they can be sold as larger shrimp. Check your label and make sure that it lists only "Shrimp" before purchasing.

Types of Shrimp

Brown, White, and Pink Shrimp

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Domestic brown shrimp

When most Americans think of shrimp, they're envisioning brown, white, or pink shrimp.

  • Brown shrimp mostly come from the Gulf of Mexico, though they're found down the entire Atlantic coast. They like it warm, so they're found in shallow waters, and tend to be fairly small with a purple-ish coloring on the tail. Firm in texture, their flavor isn't the strongest, though they're thought to have a distinctive mineral-y iodine shrimp flavor.
  • White shrimp tend to be a little more tender and sweet. With a slightly lighter color and a green-hued tail, they're found along the Atlantic and Gulf coasts in shallow, muddy waters. There's also a good number of white shrimp imported from Latin America—especially Mexico and Ecuador—Thailand, and China, all with varying levels of sustainability ratings (see the seafoodwatch reports for more details.)
  • Pink shrimp are some of the tastiest shrimp you can find, mild and sweet without the distinctive ammonia taste some of the brown and white shrimp have. Just don't expect a vibrantly hued patch of shrimp at the market—pink shrimp can range from white to gray in color. You can recognize them by dark blue coloring on the tail; they usually also sport a spot on either side of the body, about three quarters of the way to the tail.

Tiger Shrimp

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Found mostly in Asia, especially in Thailand, Vietnam, Taiwan, and China, tiger shrimp have telltale brown striping on their bodies. There are currently non-native tiger shrimp populations found off the Eastern coast of the United States as well. They can get enormous in size, up to a foot long, and are the most commonly farmed shrimp in the world. Farmed or fresh, they can have a distinctly shrimpy flavor, though you might want to check seafoodwatch for reports on its environmental impact in Asian farms. You'll frequently find them frozen in five-pound blocks in Asian markets.

Spot Prawn

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[Photograph: Shutterstock]

Generally, among English-speakers, the word "prawn" is used more in the UK, Europe, and Australia, while the word "shrimp" is more common in North America. Some people may have the mistaken impression that a prawn is necessarily a bigger creature than a shrimp (possibly due to the other meaning of the word shrimp). In reality, there's no rhyme or reason to nomenclature beyond regional preference.

Yet for whatever reason, even in the US, the spot prawn is always referred to as a prawn and not a shrimp. It's found along the Pacific coast from Alaska down to Mexico, and is a delicacy in British Columbia and the Pacific Northwest. A fairly large shrimp, at up to a foot long, spot prawns are prized for their sweetness and tenderness.

Rock Shrimp

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[Photograph: Shutterstock]

Rock shrimp are deepwater residents, growing tough and hardy in the cold waters off the Atlantic coast from Virginia down to the Gulf. A few species also live off the Pacific coast. They don't look at all like their warm water cousins, boasting a very hard (dare I say rock-like) shell and segmented flesh that looks more like a lobster tail than anything else. It tastes, not surprisingly, kind of like lobster, more firm than other varieties of shrimp, but also more sweet. It's excellent in preparations that typically call for lobster, and a whole lot cheaper to boot. It's pretty much impossible to remove that tough shell without a dedicated machine, so it's usually sold pre-peeled.

Labeling and Environmental Impact

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There are dozens of commonly sold varieties of shrimp, and, crucially, almost no enforced rules about what a fishmonger, packager, or retailer has to reveal about them. "All of the seafood that's sold in the US is supposed to be labeled with the country that it's from, whether it was farmed or wild," says Santi Roberts, the science manager at the Monterey Bay Aquarium Seafood Watch program and the most widely accepted guide to sustainable seafood.

"But there are a lot of loopholes," he elaborates. For example, any shrimp that's "processed" is completely exempt from Country of Origin and farm vs. wild labeling requirements. The majority of shrimp qualify for that exemption: If a shrimp has been deveined, peeled, frozen, beheaded, packaged, or cooked, USDA regulations do not require that you, the consumer, know where it's from or how it was caught.

That's why, he says, if you're concerned about the environmental impact of your purchase, you'll want to do some research before buying shrimp. Some methods of shrimp fishing can be extremely destructive—otter trawls are known to damage the ocean floor, often catching and killing endangered species in the process.

Meanwhile, the majority of imported, farmed shrimp is typically raised in ponds, which can absorb chemicals from its surroundings and release pollution. Shrimp sometimes escape the ponds and wreck the native populations, can use large amounts of water, and even spread disease. There are exceptions, such as some recirculating systems, that are just fine. But make sure these are labeled specifically as raised in a recirculating system if you're looking to support those operations. Seafood Watch also likes the newish Selva verification, which is visible as a label.

On the whole, freshwater shrimp tend to be more sustainably farmed or caught than ocean shrimp. To purchase accordingly, you can look for certain labels: independent regulatory groups will slap labels on shrimp they approve of, so look around for names like the Marine Stewardship Council, Aquaculture Stewardship Council, and Naturland.

These quality groups are not to be confused with various promises from the seller of the shrimp, like "sustainable," "natural," or "organic," the latter of which has virtually no weight at all; the USDA does not have official organic standards for seafood. Descriptions like those have no legal or regulatory weight behind them, meaning that anyone can claim them and nobody's checking. There are also no rules about how a seller has to identify the type of shrimp; a common species like Litopenaeus vannamei could go by names ranging from Pacific shrimp to white shrimp to whiteleg shrimp to just "shrimp." It could come from Mexico or Thailand or Venezuela or China. At the end of the day, stick with labels stating that an independent organization has examined and approved of the shrimp if you want its provenance, sustainability, and authenticity assured.