Keep it Fresh
Just like any seafood, the most important thing to remember when buying shellfish is this: the fresher, the better.
- If possible, shop at a fish counter that's always busy--this way, you can be assured the fish hasn't been sitting around long.
- Seafood should smell fresh and briny, not distinctly "fishy."
- Look for clean ice surrounding the fish. The care fishmongers put into clean fresh ice is a good indicator their commitment to quality seafood.
Clams, Mussels, and Oysters
Along with smelling fresh, the shells on clams, mussels, and oysters should be tightly closed. If there is a slight opening, give it a tap: if the shell quickly closes, it is still alive--if not, discard it. Store live shellfish in the refrigerator, covered with a wet towel to keep them moist. Allowing them to breathe will assure they stay alive and fresh until cooking time.
Shrimp and Prawns
Shrimp can be found raw or cooked, peeled or unpeeled, and in a variety of sizes. Normally, the size is expressed by the number of shrimp per pound, such as 18/20 or 12/14. If you’re buying raw shrimp, freshness is again the key. Unpeeled shrimp are more work to eat, but the shells impart more flavors to the finished dish. If you purchase unpeeled shrimp, save the shells in the refrigerator or freezer and use them to make a shrimp stock or shellfish court-bouillon.
Crab and Lobster
Crab and lobster can be found either alive, for steaming or boiling at home, or already cooked. Whole, cooked crab is common, as is lump crabmeat. Live crab and lobster should be kept in the refrigerator, still wrapped from the fishmonger, until ready to cook. For crab, follow the recipe for boiled lobster but shorten the cooking time to 5 to 10 minutes depending on the size and type of crab.
With scallops, the freshness rules still apply, along with determining whether they are "wet packed" or "dry packed." Wet-packed scallops are treated with a chemical that allows them to retain more water. Try to find fresh, dry-packed scallops. They will taste fresher, cook more easily, and have none of the residual chemical flavor often noticed in the wet-packed variety.