have a wonderful characteristic. Cooked for just a moment, scallops always stay tender. (Unfortunately, when they're overcooked, they become rubbery.) Their tenderness is surprising, because in America we only eat the muscle. (Europeans savor the roe, which is discarded here.) The muscle becomes disproportionately large because of the way scallops travel through the water, moving their shells together, expelling a jet of water.
At the market you'll basically find two kinds of scallops, large sea scallops
caught miles out at sea that are available year-round, and tiny bay -- or Cape -- scallops that live in shallow coastal waters and are available during the winter months in the north.
Bay scallops will never get as large as sea scallops because they're an entirely different kind of scallop. The famous Cape Cod scallops inhabit waters that are continually flushed with high tides, which helps keep the water clean. For some reason, the sugar content of scallops seems to be higher when they are traveling through unpolluted waters. When you cook Cape scallops. they brown quickly and taste almost sugary. As they get older, they lose that sweet flavor and take longer to brown, one way to tell how fresh they are. Scallops from other parts of the country never brown as fast, and never seem to have as much flavor.
Similar to other shellfish, bay scallops are now being grown commercially. It makes sense to grow scallops commercially because if they are not harvested after a couple of years, they die.
Many supermarkets sell Calico Bay scallops, found in Florida's waters and shipped around the country. We don't use them in our restaurants because they are already slightly cooked by the time they reach the customer. These scallops are so tiny that in order to open them easily, the processors steam them for a few moments which causes the scallops to lose some of their juices and flavor.
Try to buy fresh scallops, which a far preferable to the frozen kind. If you live in an area where the markets stock only frozen scallops, cook them while they are still partially frozen. Once they thaw out completely, the scallops have lost too much of their juices. One caution: some purveyors soak shucked scallops in water or a phosphate solution. This increases volume by almost a third and whitens the fish, but diminishes the flavor.
Scallops cook almost immediately which makes them a boon for the busy cook. But cook them barely at all, otherwise they'll become tough and rubbery. Tiny bay scallops are most at risk for poor cooking procedures.