How to Shuck
Before opening oysters, scrub them with a stiff brush and rinse well. Then determine which way is up: The top shells of oysters tend to be flatter than the more bowl-shaped bottom shells. For serving on the half shell, open the oyster with its top shell facing up, and leave the oyster in its bottom shell.
Use an oyster knife, which has a thick handle for easy gripping and turning. Its wide, dull blade is strong enough to lever open the shell. (Although similar to clam knives, oyster knives are stubbier.) Stainless-steel oyster knives will not transfer any metallic flavor to the oyster.
1. For protection and a better grip, use a folded cloth or an oven mitt to hold the oyster in one hand. (Right-handers should hold the shell with their left hand, and vice versa.) Position the shell so the rounded edge points out toward the space between your thumb and your fingers and the hinge end points toward you.
2. Holding the oyster knife in your other hand, insert its tip into the dark, rounded spot at the oyster's hinge. (The shell's ridges and dark rays emanate from the hinge.)
3. Twist the knife sharply to break the hinge.
4. Once the shell opens, slip the knife carefully up along the inside surface of the top shell, severing the adductor muscle that grips it. Take care not to cut the oyster itself or to spill its liquor.
5. Lift the top shell away and discard.
6. Carefully cut the muscle under the oyster to loosen it from the bottom shell. Remove any small particles of shell.
There are a few ways to open a large number of oysters quickly for use in a recipe. Do not try to use these methods for raw oysters on the half shell, because they will be partially cooked and thus very unpleasant.
The first way is to steam them for about 1 minute. Use very little water, so the liquor that drains from the open oysters will not be overly diluted.
Another trick is to spread the oysters in a large, shallow baking dish and heat the oysters in a 375°F oven just until they open, 1 to 2 minutes. Or, you can microwave them on high for about 1 minute.
Adapted from Williams-Sonoma Kitchen Companion: The A to Z Guide to Everyday Cooking, Equipment and Ingredients (Time-Life Books, 2000)