The lobsters sold in the United States are either cold-water lobsters or warm-water lobsters, and, although they taste similar, there is a big difference. Cold-water lobsters, sometimes known as Maine lobsters, are dark, usually black or brown but sometimes greenish, and have two large front claws. Many come from Maine, but some come from the cool waters farther down the coast.
Warm-water lobsters, sometimes called Florida lobsters, spiny lobsters, or rock lobsters, usually come from the Caribbean or the Gulf of Mexico. Spiny lobsters don’t have the big meaty claws of the cold-water specimens, and they tend to be tan or orange. They look more like humongous shrimp with really thick antennae. Use warm-water lobsters when you only need tails.
You want a cold-water lobster for this recipe because you want the toothsome claw meat.
Cold-water lobsters usually weigh 1½ to 2 pounds. A typical 1½-pound lobster will have less than 1 pound of raw tail and claw meat. Pick an animal that is lively—walking or swimming. A listless specimen with a curled tail and meat visible between the tail and the upper thoracic carapace is a bad choice. Don’t worry if there is a little green algae in the lobster tank.
Live cold-water lobsters will have rubber bands on the large front claws. Leave them on until after the animals are dead unless you type with only two fingers like me. Always grasp a lobster from above by the solid shell on the upper half, never by the tail. There are some sharp edges on that tail that can gash you, even when the lobster is dead.
You should cook a live lobster the same day you get it, although it will stay alive and fresh in the fridge for 2 to 3 days if it has been handled well. Never submerge a saltwater lobster in fresh water. This will kill it. If you have to keep it a day or two, put it in a pot so it does not crawl around in the fridge, put about ¼ inch of water in the bottom to keep it moist, and cover it with a damp cloth or newspapers. Lobsters can breathe air, so they will be fine. Do not cover with ice.