Briny, succulent, and sweet, clams make great party fare. A heaping platter of steamed clams takes only minutes to prepare and is perfectly suited to picnic-table dining with no fancy accoutrements other than melted butter and cold beer. The only real trick to clams is knowing what’s what at the seafood counter.

Clams are separated into two categories—softshell and hard-shell. The name “soft-shell” is a bit of a misnomer, since the shells aren’t truly soft, but they are thin and brittle. These clams have a dark, hose-like protuberance that keeps the elongated shells from closing tightly. This neck (or foot, as it’s sometimes called) is used to siphon and release ocean water and earns these clams the nicknameslongneck clams or pisser clams. Because soft-shell clams gape open, they’re highly perishable and should be cooked within a day of purchase. Soft-shell clams also tend to collect more sand and grit than other clams, and many recipes will instruct you to first soak them in a bowl of cold salted water for a few hours to purge the sand.

Soft-shell clams are never eaten raw, and the most common way to prepare them is by steaming or frying, hence their other nicknames,steamersandfryers. When steaming, most cooks skip the soaking step and simply serve the steamed clams with a bowl of clam broth (the liquid they were cooked in) for dipping to rinse off any grit.

Hard-shell clams come in many shapes and sizes.On the Atlantic coast where clams reign, the most common variety of hard-shell clam is thequahog(pronounced KWAH-hahg) with its thick, tough, pale-colored shell. Quahogs are sold according to size, and their size determines how they’re best eaten. The largest of these are sold aschowder clams, and are best used for just that—chopping up to add to chowders and stews. Chowder clams can be as big as your fist and weigh anywhere from 5 ounces and up (a single chowder clam often weighs over 1/2 pound). Because of their size, they tend to be tough and not as sweet as smaller varieties.

Cherrystone clams下一个尺寸的圆蛤类,小于3-inches across and in the 2- to 4-ounce range. These are sweeter and more tender than larger clams and are excellent for stuffing and broiling. They are sometimes eaten raw, although some people consider cherrystones just a bit too large to be eaten on the half shell.

Littleneck clams,named for Littleneck Bay on Long Island, are the smallest, most delectable, and most expensive of the quahog clams. Measuring 1-1/2 to just over 2 inches across and weighing a mere 1-to 2 ounces each, these tender little clams are the best for eating raw, steaming whole, or adding whole (steamed in their shells) to dishes such as pasta sauce or seafood stew.

Mahogany clamsare another variety of hard-shell clam, easily recognizable by the reddish-brown color of their shells. Commercially known asocean quahogs, they can grow quite large, but most are harvested in the 1 1/2- to 3-inch range and can be used anywhere you’d use cherrystones or littlenecks.

Surf clams or hen clamsare a large variety of hard-shell clam with very pale, triangular shells, but they’re rarely sold retail in their whole form. Because of their size and subsequent toughness, surf clams are most often processed and sold in cans and frozen as chopped clams.

When buying live clams,tap the shells to detect some movement—a retraction of the neck for soft-shell clams or the snapping closed of the shells for hard-shells. If the clams don’t respond, they’re dead, or dying, and should not be eaten. Store clams in an open bag in the refrigerator.