Poaching is a special cooking method similar to American style poached eggs, which means to cook in liquid just below the boiling point. In addition to eggs, a whole chicken can also be prepared through poaching. Poaching is especially good for cooking delicate fish or boned fowl in a clear soup, slowly simmering until the meat is tender.
Poaching is the process of gently cooking food immersed in liquid. It can be almost any food, and it can be almost any liquid. The process is most often used for delicate food such as fish, chicken breast, eggs and fruit that can be damaged easily during the cooking process. However, it is frequently used in Chinese “red-cooked” pork shoulder and chicken. It is extremely important that at no time should the liquid boil – keep it to a bare simmer.
Use a pot that is just large enough to hold the food (to minimize the amount of liquid used). There is a special long thin poaching pan for whole fish with a removable rack to lift the fish safely out of the poaching liquid. Filets of fish are traditionally poached in an oval, tin lined copper pan but any non-reactive pan will do fine. It is important that you use a pan made from a metal that will not react with acid, such as stainless steel or enameled cast iron when there is wine, tomato or citrus in the poaching liquid. Acid reacting with aluminum or unlined cast iron will discolor the sauce and give it a bitter metallic taste. The food is placed in warm poaching liquid and brought to a bare simmer that is maintained for the duration of the cooking process. The food is usually allowed to sit in the liquid for approximately 10-20 minutes to absorb all the flavoring, before being removed to serve.
Large fish such as salmon, arctic char, and ocean trout are generally poached in a court bouillon, a very light acidic liquid made with water, dry white wine, lemon or vinegar and some aromatic vegetables (onion, leek, carrot, fennel) and a herb bouquet (parsley, bay leaf, thyme). You can simply use salted water with some vinegar or lemon juice added. The acidity improves the texture of the fish. Poaching a large fish is very easy; it can be served hot or cold as part of a buffet with a variety of sauces or flavored mayonnaise.
Small pieces of fish or filets are generally poached in fish stock, white wine or a combination thereof that is then reduced and finished as a sauce. The filet should be started in cold liquid so that it will not cook unevenly. Boiling water will cause the outside of the fish to seize up and become overcooked before the center is cooked. Small fish and filets should be covered with well buttered waxed or parchment paper to retain moisture, and brought slowly to the barest simmer on top of the stove before being placed in a 325-degree oven to finish the very slow, gently cooking.
Filet of sole and flounder lend themselves well to poaching. The process is completed in about seven minutes and there are a large number of saucing suggestions. Escoffier has 80-some recipes for filet of sole. The filet is placed on a bed if vegetables and poached in a good fish stock that is then reduced and used to make a flavorful veloute sauce (see white compound sauce). Try tomato and shallot finished with parsley; mushroom and shallots finished with parsley.
Shrimp should be placed in cold court bouillon or water flavored with herbs and lemon juice, and brought slowly to a bare simmer. The shrimp should then be drained and quickly chilled and refrigerated until use.
Poaching is an excellent technique for chicken to be used in salads or as a filling for wraps; it retains moisture very well. Use chicken stock or water and aromatic vegetables and bring the chicken to a bare simmer. Turn off the heat and allow the chicken to sit until cool. Refrigerate until ready for use.