How to cook fish and shellfish with a moist-heat preparation
Poaching. Fish is a delicate food suitable for poaching. The lower water temperature of 160° to 180°F (71° to 82°C), which keeps bubbles small and clinging to the sides of the pan, protects the delicate flesh of fish. If a whole, drawn, or dressed fish is being poached, it can be wrapped in cheesecloth to hold it together. The liquid may be a court bouillon or a fumet. Although fatty fish such as salmon can be poached, best suited for this method are white, lean fish such as cod, pike, haddock, flounder, sole, whiting, red snapper, halibut, and bass. Sole fillets are thin enough to make paupiettes, or rolled fillets.
When poaching fish, the water should never be allowed to boil. Boiling causes flavor loss and toughens the fish, while low temperatures retain maximum flavor and moisture. A well-seasoned poaching liquid is also important. Seasonings and/or chopped vegetables such as tomatoes or shallots add flavor, texture, and color. The poaching liquid is often reduced and sometimes thickened for use as a sauce. The fish is placed in the middle of a baking or frying pan and cooking liquid is added until it covers up to an eighth to a quarter of the fish’s thickness. Some recipes call for covering the entire fish in liquid, but too much liquid may dilute delicate flavors. On the other hand, too little liquid will evaporate and cause the fish to dry out during cooking.
Fish fillets can be poached in an oven set at 350°F (180°C) or in a pan on top of a range set at poaching temperatures. The pan can be covered to trap more heat and moisture and to prevent volatile flavor compounds from escaping. This technique, when using only a small amount of liquid, is more akin to steaming, another moist-heat method.
Simmering. Simmering uses slightly higher temperatures than poaching-180°F (82°C) to just under boiling, where gentle bubbles rise but barely break the surface. This method is most often used to cook shrimp, even though the expression “boiled shrimp” is commonly used for the outcome of this process. Shrimp are often simmered and then chilled, shelled, and deveined for shrimp cocktail. Lobster, crab, and crayfish may also be simmered. The live lobster, crab, or crayfish is killed by inserting it headfirst into boiling water that has been salted with 2 teaspoons per quart. Prior to placing crayfish in the water, the middle tail fin must be grabbed, twisted, and pulled to remove the stomach and intestinal vein. Lobsters will curl their tails when first dropped into the water, which may cause toughening. It is prevented by killing the lobster with the point of a sharp knife inserted directly between the head and the shell. A more expensive technique involves submerging the crustacean in a container of beer or wine, which inebriates it and causes it to relax. Once the shellfish is submerged, the water is brought back to a boil and then immediately reduced to a simmer. Heating time averages 5 minutes per pound for a lobster; a whole crayfish takes less than 7 minutes. When done, the crustacean is immediately removed from the water to prevent further cooking, drained well, and served at once with clarified butter and lemon. Lobsters are often split in half at restaurants for the diners’ convenience.
Steaming. Fish can be steamed in the oven if they are tightly covered in a baking dish, aluminum foil, or parchment paper, or in a pan on top of the range. When fish is wrapped with parchment paper, along with seasonings and aromatic vegetables if desired, and cooked in the oven, this is known as cooking en papillote. When the fish is done, the parchment envelope puffs up, turns brown, and provides a dramatic presentation. Each person may then be served a portion still wrapped in its own paper package, making for a novel dining experience. Fish may also be cooked in foil envelopes, although these are generally removed before the fish is served at the table. Regardless of the way it is accomplished, steaming heati the .fish in its own juices, which locks in the flavor and aroma.
Steaming can also be used to prepare lobster tails, clams, and mussels. Frozen lobster tails are thawed and “saddlebacked,” which involves splitting the tail by cutting through the hard top shell and pulling the meat out so it lies on top. The tail is then seasoned and steamed shell-down in a covered pan for a few minutes. Clams and mussels are steamed by placing them in a covered pot with a small amount of liquid on the bottom. Steaming clams or mussels just until the shells open does not kill microorganisms, so it is important to steam them for about 5 minutes or to a temperature of 145°F (63°C). Pressure steaming is not recommended because it tends to toughen both fish and shellfish.
At a clambake, clams are actually steamed rather than baked. A hole a foot deep and 3 feet wide is dug into the sand and lined with smooth, round rocks. This serves as the base of a fire that will be kept going for two or three hours after the rocks and/or embers have been heated hot enough. The embers are raked over the rocks and removed, and soaked seaweed is placed over the rocks to a depth of about 6 inches. Chicken wire mesh is laid over that to serve as a platform for a layer of hard-shell clams, which are then covered with sweet potatoes, followed by broiler chickens cut into quarters. partially husked corn, and then a layer of soft-shell clams. The whole pile is splashed with a bucket of seawater, covered with a wet tarp, and allowed to “bake,” or rather steam, for about an hour. Doneness of the clams is tested by checking to see if their shells have opened. The chickens take longer and thus need to be tested for doneness separately.
Microwaving. Almost any form of fish can be microwaved. If it is commercially frozen, the defrosting instructions on the package should be followed. In general, instructions call for arranging fish fillets or steaks or small fish in a single layer, with thicker portions toward the outside of a microwave-safe dish. Desired seasonings and dots of butter are added before covering with plastic wrap to trap the moisture. Poaching can also be done in the microwave oven.