July 19, 2018
Seafood soup of clams Paila marina in clay bowl

Clams: Rich in Iron and Vitamin B12

by Berkeley Wellness

For the most part, clams are caught in local waters. Easterners eat Atlantic clams, and Westerners enjoy Pacific varieties. Clams are harvested by digging them from the sand at low tide or are scooped from beds in deeper waters. They are similar on each coast.

Clams may be hard-shelled or soft-shelled. The edible portion consists of the muscles that operate the shell—the siphon, or neck, and the foot, which the clam extends from the shell to propel itself through sand. In general, clams are sweet and a bit chewy, though flavor and relative tenderness depend on the size and species.

In recent years, the danger of contamination has made it risky to eat raw clams. Raw shellfish may harbor various kinds of bacteria and other potentially harmful organisms. However, clams are popular and safe when baked, or in chowders and pasta sauces.

Clams: nutrition

Clams are a remarkably rich source of iron. These bivalves also supply other minerals, including selenium and zinc. In addition, clams are an excellent source of B vitamins in general, and they are an exceptional source of vitamin B12. A half dozen cooked clams has only 166 calories but supplies 40 times the required daily amount of vitamin B12.

For a full list of nutrients, see Clams in the National Nutrient Database.

Types of clams

Butter clams: Butter clams are small Pacific clams with a smooth shell. They are available primarily canned, especially as smoked clams.

Geoducks: Pacific geoducks are large soft-shelled clams weighing 2 to 4 pounds each, with sweet, tasty flesh. They can be shucked, chopped, and sautéed, and also make a tasty chowder.

Manila clams: These are very small West Coast clams sold as steamer clams.

Pismo clams: Large Pismo clams, found off the California coast, are scarce and delicious.

Quahogs: This hard-shelled clam is the largest eastern type, ranging from about 1 1/2 to 6 inches across. The clams called cherrystones and littlenecks are not different species, but just smaller-sized quahogs. Cherrystones measure less than 3 inches across and littlenecks about 2 to 2 1/2 inches. (There is also a West Coast clam called a littleneck, though it’s a different species.) Full-sized quahogs are sometimes called chowder clams, as they can be tough and are best cut up and cooked.

Razor clams: Long, skinny razor clams are named for their resemblance to an old-fashioned straight razor and the sharpness of their shells. They are commercially marketed on the West Coast, but not in the East. Razor clams are sometimes available in Asian and specialty seafood markets.

Steamers: A third type of eastern clam is the soft-shelled steamer, which has a long siphon that projects from a thin, brittle shell. As the name suggests, this type of clam—about 2 inches long—is usually steamed, but it can also be shucked and then sautéed or deep-fried.

Surf clams: Also called sea clams, skimmer clams, or chowder clams, surf clams are the most common eastern species. Large and comparatively tough, they are commonly cut up and used in recipes. Most surf clams are found canned.

Cooking with Clams

Clams are iron-rich shellfish ideal for chowders, pasta sauces, or simply steamed.

How to shuck clams

Unless you have experience shucking live clams, it’s safer and faster to have this service performed by the fish seller. If that isn’t possible, or you want to store the clams unshucked, then do it yourself. Be sure you have the right tools:

  • A clam knife is about the size of a paring knife, but has a stronger, wider blade and a rounded tip.
  • It’s not uncommon for the knife to slip while you’re applying pressure to open a shell, so wear a pair of rubber or work gloves to protect your hands.

To shuck clams, first discard any clams with broken or gaping shells as they have died and are not fit to eat. To prepare the remainder, scrub the shells and rinse under cold running water.

All clams should be rinsed—and preferably also swirled about—in several changes of cold water to loosen the grit they accumulate. Some people like to take this a step further and purge the grit by soaking clams in salt water, usually a gallon of cold water to which 2 teaspoons of salt have been added. You can also try using a cup of cornmeal instead of, or in addition to, the salt. Let the clams sit in this solution in the refrigerator for two to three hours.

Hard-shelled clams are easier to open if you place them in the freezer for 10 minutes beforehand.

Hold a clam in your gloved palm, rounded-side up, with the shell’s hinge toward your wrist. Working over a bowl to catch the juices, push the knife blade between the shell halves from the front. Twist the knife when it is well inside to separate the shell halves. Cut the muscles on each side of the hinge, then cut the interior muscles to free the clam.

When opening soft-shelled clams, you’ll also need to pull off the dark membrane that covers the edible “neck” of the clam.

Also see How to Buy Seafood.