How do I check that clams are alive?

Name: Cioppino (Fisherman's Stew)
Prep time: 45 min
Cook time: 60 min
Total time: 105 min
Ingredients: ¼ cup + 2 tablespoons extra-virgin olive oil, (divided); 2/3 cup finely chopped shallots, (from about 3 shallots); 3 cloves garlic, (minced); 1 cup white wine; 1 (28-oz) can crushed tomatoes; 2 (8-oz) bottles clam juice; 2 teaspoons sugar; 1¾ teaspoons salt, (divided); ½ teaspoon crushed red pepper flakes; ½ teaspoon dried oregano; 7 sprigs fresh thyme, (plus 1 teaspoon fresh chopped thyme); 1½ lbs firm-fleshed fish fillets, (such as halibut, cod, salmon, snapper, etc., cut into 2-in (5-cm) pieces); 3 tablespoons unsalted butter; 1½ lbs (about 18) littleneck clams, scrubbed (see note); 1½ lbs extra large raw shrimp, (peeled and deveined); Fresh chopped Italian parsley, (for garnish (optional))

Question

Accepted Answer

First, make sure all of the shells are tightly closed. If any clams are open, gently tap them against the countertop; if they are alive, they will close their shells. Discard any clams that do not close their shells or that have cracked or chipped shells.

Ingredients

Instructions