Characteristics of Shellfish

Abundant, versatile and masterfully prepared with little more than good olive oil and sea salt, shellfish exemplify elegant simplicity. Knowing the characteristics, varieties and best uses of shellfish give you the fundamentals you need to make the most of these gems of the sea.

Shellfish are classified in two groups: mollusks, which consist of clams, mussels, scallops and oysters, and crustaceans, such as lobsters, prawns, crabs and shrimp. Unless you live on the coast, less-common varieties of shellfish -- such as whelk, periwinkle and conch -- take a little work to track down, but their special flavors and textures make the effort worthwhile.

Shellfish work with nearly every cooking method -- steaming, poaching, grilling, frying and roasting each produce different results. Gentle, moist-heat cooking techniques, such as steaming and poaching, best preserve the subtle flavor and delicate texture of shellfish. However, several preparations -- such as lobster thermidor -- rely on high, dry heat for caramelization.

To make a simple lobster thermidor, simmer lobster tails until just cooked through, about eight minutes. Next, split the tails in half lengthwise, scoop out the flesh and saute it until caramelized. Mix the flesh with bechamel sauce, sauted onions and Parmesan cheese. Return the flesh to the tail shells, sprinkle with panko breadcrumbs and dot with butter. Bake the tails in a 350-degree-Fahrenheit oven until golden brown.

Shellfish work with several seasonings and flavoring elements, particularly citrus and floral herbs. Fresh shellfish usually needs only a touch of sea salt, freshly ground black pepper, olive oil and freshly squeezed lemon juice to accent its subtle sweetness, but several traditional spice blends are available for specific preparations, such as seafood boils and clam bakes. Herbs and spices to try with shellfish include thyme, parsley, dill, smoked paprika, lemon balm and sage.

Market forms of shellfish include shucked, live-in-the-shell, Individually Quick Frozen, or IQF, and peeled-and-cleaned. IQF shellfish are flash frozen immediately after being shucked or peeled and cleaned. Peeled-and-cleaned shrimp have the intestinal vein and head removed and the shell peeled. Live shellfish are usually sold to seafood markets within a few hours of harvesting.

When purchasing live shellfish, check for quality -- clams', scallops' and oysters' shells should close when tapped; a lobster's tail should curl when touched; crab's legs should move. Pat thawed shellfish dry with a paper towel prior to cooking; the excess moisture from melting ice crystals create steam and prevents browning. Frozen and shucked clams, oysters and scallops are ideal for cooking but not raw consumption.