Cooking analogies work well when we picture our own bodies as the morsels to be cooked. When I teach students how to poach, I tell them to picture themselves slipping into an unbearably hot bathtub. Their flesh will tighten for a while and then relax. If the water is too hot, they will be flung about by the bubbles and the heat will be too much of a shock to the system, rendering them dry and stringy. Too cool, and it’s a glorified hot tub; they will be raw indefinitely.
Our previous Cooking School columns — simmering, stewing, and braising — were focused on breaking down tough cuts of meat through slow, moist cooking where tough connective tissue turns to luscious gelatin. Poaching is, to some extent, the converse. Tender, delicate items — eggs, shrimp, scallops, chicken breasts, fish fillets, ripe fruit — are warmed just until they reach desired doneness. Where the other methods break tough textures down, poaching builds them.
Poaching works best with delicate, tender foods. The food is immersed in water, or better, a flavorful liquid like stock, juice, milk, vegetable puree, or just about anything. Often the poaching liquid is acidic for flavor and to help with protein coagulation. The classic French poaching liquid is the court bouillon, made with water, wine, lemon, and vegetables like celery, onion, and mushrooms. The best poaching liquids can later be used as a sauce or reused for poaching something else, picking up flavor from each additional item.
Back to the bathtub. A good hot bath is warmer than body temperature, up to a maximum of about 120°F. Hot food held in a steam table has a minimum temperature of 140°F. Poaching is the next level up — about 160°F. When you observe water at that temperature, it is quaking slightly with small bubbles rising up but not really breaking the surface. Chefs sometimes say, “when the water smiles, it is ready.” Chefs also say less poetic things. Above the poach is the simmer, where bubbles lazily break the surface, starting around 180°F and, of course, above that, the boil at 212°F.
When protein-rich foods like poultry, fish, and shellfish cook in the poaching liquid, the protein denatures, losing its structure. This is true for all proteins, but is best visualized in an egg where you can see it happening before your eyes. When the egg enters its bath, the proteins in the whites are intact and organized, allowing you to see through them. As the heat destroys the integrity of the cells, the proteins form a messy web, turning the translucent egg white opaque. You can see a similar transformation in a white-fleshed fish like flounder, a prime candidate for poaching.
Low-temperature cooking is all the rage in culinary circles for good reason. Poaching just until the food meets culinary and food safety guidelines allows it to retain a lot of moisture and lose relatively little flavor to the liquid (using a barrier like plastic helps in that area and will be discussed in the next Cooking School.) The cooking liquid (eau de cuisson in French) can then be served with the food, reduced to form a sauce, or reused.
Because of its simplicity, poaching, variously called, can be found in nearly every culture. Recognize it as tender items, gently cooked, in flavorful liquid. Because it doesn’t have the flavor impact of a grilled or braised item, a good poach is underappreciated but can go far beyond eggs at brunch. •
Recipes by Ally Zeitz