Few foods have as much to gain from the grill as seafood. Shellfish, in particular, can come off the grill spectacular, provided you know what you're doing. When it comes to shellfish, timing is everything. Sea scallops, for instance, can go from perfect to rubber in a matter of seconds. But don't let the challenge scare you off. The smoky grill flavor can turn even relatively inexpensive shellfish into a five-star gourmet meal.
First of all, let's clarify what we mean by shellfish. Of course, you'd think that these are fish with shells. Unfortunately, it isn't that simple. Shellfish fall into two main categories, crustaceans like crabs, shrimp and lobster and mollusks like clams, oysters, and squid. Squid (eaten as calamari) along with octopus is a subcategory of mollusks called cephalopods.
What Type of Heat to Use When Grilling
To get the benefit of grilling the meat of shellfish, it needs to be exposed to the direct heat and flame. For instance, when grilling shrimp you need to remove the shell or you might as well boil them. Out of the shell allows the meat to soak in that grill flavor. Similarly, clams and oysters will simply steam in their shells and won't gain the smoke flavor. Of course, some things are just easier in the shell so don't worry about removing or cracking every shell.
As a general rule, shellfish, like all fish, should be grilled over a medium-high to high heat. You will want to cook it fast to keep in the juices and avoid drying out the meat. Small items, like medium shrimp or scallops, should be placed on skewers (we prefer bamboo because it holds better) or cooking in a grill wok or similar grill-safe cookware.
Timing of Grilling Shellfish
With a hot fire and the food secure for the grill, the next challenge to grilling seafood is the timing. If you overcook the shellfish, it will become tough and rubbery. Of course, this is the challenge no matter how you prepare it. The flesh will become opaque and lose its shiny surface. Generally, you should get just a touch of browning from the heat. With shrimp, the entire surface will turn pink. This is the time to take it off the grill. It's better to remove and check than to wait too long.
Grill Directly on the Grate or Use a Grill-Safe Pan?
The great thing about grilling mollusks is the ease. Placed on a hot grill, they will cook up a matter of minutes. This is a great way to serve up an appetizer without leaving the patio. Everyone will be so impressed and you can quickly turn to other dishes while these little treats quickly disappear.
You will want to grill clams, mussels, or oysters on a grill-safe pan or even a piece of aluminum foil (punch a couple of holes in it). The direct flame can burn the shells and that tends to be unappealing. Squid, or in this case calamari while still being a mollusk is a different fish altogether. It is grilled much more as you would shrimp.
When selecting mollusks in the shell make sure that the shells are closed tight or snap shut when tapped. Clams, oysters, and mussels in the shell need to be rinsed in cold water to remove any sand. Always grill on a medium-high to high heat.
How to Grill Each Type of Shellfish
Clams need only be washed off in cold water and put right on the grill. Close the lid for a couple of minutes and then wait for the shells to open. When they do, remove and serve.
Mussels require a little more preparation. The shells need to be cleaned of beards before they hit the grill of they just might catch on fire. Once cleaned they cook just like clams. Remember to be ready to serve these little morsels before you put them on the grill.
Oysters grill just like clams with one exception. Because of the shape of oysters, you will want to grill them with the cup side down to hold in the juices. There are products on the market to help you grill things like this. Great Grate is a specially designed grill topper that holds oysters and mussels in the perfect position to get them cooked without letting the juices escape.
Scallops are generally bought out of the shells. These are wonderful grilled because of the direct access that the meat has to the smoke. However, they can quickly overcook and dry out. Place on skewers, grill on medium-high heat and keep some melted butter handy to baste them right before you remove them from the grill. Like all shellfish, you will want to serve these morsels right from the grill.
Typically when grilling crustaceans you will want to remove or crack the shells. This not only allows for even cooking but will introduce the smoke flavor into the meat.
Crab comes in a variety of shapes and sizes. The most important difference is between hard and softshell. Softshell crabs can be cleaned and grilled directly. They will be done when the leg meat is opaque. It usually takes about 10 minutes on a medium-hot grill flipping once. Hardshell or live crabs need to be similarly cleaned. The best way to prepare live crabs is to first throw them headfirst into boiling water. To clean a crab, flip it over and pull the triangular tab from the bell and lift off the shell. Clean out the entrails and gills. Wash and drain. Grill shell off. You can replace the shell (thoroughly cleaned of course) after cooking.
Crayfish come in about 400 varieties. These small lobster-like creatures are a delicious treat grilled. Throw live crayfish into boiling water headfirst. Remove and cut in half lengthwise, right down the middle. Start at the head with a sharp knife and cut through to the tail. Remove the intestinal tract (it looks like a thin vein running the length of the crayfish) and the sandy sac just behind the eyes. Crack the claws and rinse completely. To grill, place the cut side up on the grill. Baste with melted butter or another marinade. Turn when the shell turns bright red and complete cooking. The meat will turn white. It's important to remove when just done. It's best to use an instant-read thermometer. The temperature of the meat should reach 165 F. Test in at least two places.
Lobsters are prepared in much the same way as crayfish. Because of the larger size, a lobster will take a little longer to cook but should be done in about 10 to 15 minutes. Place halved lobsters shell side down until the entire shell is bright red. Turn and continue cooking until meat is white and the meat reaches a temperature of 165 F.
Prawns and Shrimp
Prawns and shrimp are very similar but are different. Many people believe that any large shrimp is a prawn. In fact, most stores sell them this way. A prawn is actually very similar to a tiny Maine lobster having claws and a similar body structure. However because of the similar sizes you grill prawns and shrimp in much the same way. To get the grill flavor on shrimp and prawns, you need to remove the shells (and devein while you're at it). Very large shrimp or prawns can go right on the grill, but you will want to tread smaller ones onto skewers. These cook fast on a hot grill so keep a close eye on them. When the skin turns pink on the downside flip and continue until they are uniformly pink. Remove and serve. This is another dish that you want to take straight from the grill to the plate.