The chowder clam, the cherrystone, and the littleneck are all the same bivalve species: Atlantic hard-shells, or quahogs (KO-hogs). They are distinguished by size, and the chowder is the largest (because it's the oldest, harvested at up to eight years of age), measuring more than three inches across. Too tough to eat raw, it turns soft and juicy when chopped and used in chowder or stuffed clams.
This Atlantic clam, a staple of New England clam shacks, is knows as a "soft-shell" because its oval-shaped armor (one-and-a-half to three inches in diameter) is more brittle than a quahog's. Once it's out of the water, its "neck" (actually, two siphons used for breathing and eating) protrudes through a gaping shell, so it's more perishable as well. That's why steamers are always cooked before eating.
A cherrystone clam, five to six years old and two to three inches in diameter, is the middle child in the quahog family. Smaller ones (sometimes called topnecks) can be enjoyed raw on the half shell, and larger ones are delicious steamed or grilled. Fun fact: Native Americans made wampum out of quahog shells, which led to the bivalve's Latin name: mercenaria, or "hired for wages."
Measuring from one to two inches across, the littleneck is the smallest quahog. Like chowder and cherrystone clams, it's mild and briny, but its size means it's the most tender (and prized) of the lot; the plump, juicy meat is excellent raw or cooked. Raw clams, by the way, are easiest to open after you chill them for a few hours; the cold relaxes the muscle that keeps the shell shut tight.
5. New Zealand Cockle
The cockle is not, strictly speaking, a true clam but a close relative. Since you'd use it as you would a littleneck or a Manila (linguine, anyone?), it makes sense to include it here. The cockle we commonly see in American fish markets is imported from New Zealand. It's harvested year-round but is at its briny-sweet best right now, while it's winter in the Southern Hemisphere.
This sleek, sharp-edged Atlantic soft shell is named for its resemblance to an old-fashioned straight razor. (Another of its monikers is "jackknife.") Like a steamer, it can't close its shell completely when out of water, so it's eaten when cooked; you may well have enjoyed razors in black-bean sauce at a Chinese restaurant. The Pacific razor, a different species, is longer, wider, and more strongly flavored.
Native to the western Pacific Ocean, the Manila was accidentally introduced to the Pacific Northwest in the early 20th century. Less than two inches in diameter, it has a higher ratio of meat to shell than similar clams, since its shell is thinner. As such, it offers a bit more nutrition, too: Clams are a good source of protein, iron, vitamin B12, potassium, selenium, and omega-3s.
Watch our Kitchen Conundrums expert Thomas Joseph demystify how to buy, clean, and store clams. Now you’re ready to host a clambake!