Poaching

What it is

Cooking food submerged in liquid held in a narrow, gentle window below the simmer — roughly 70–82 °C (160–180 °F) — where the surface is still and barely steaming, with at most the occasional bubble. The most delicate of the immersion techniques, reserved for foods that toughen, dry out, or fall apart under harsher heat: eggs, fish, poultry breasts, fruit.

The science

Poaching is precision protein management. Most of the foods we poach are governed by denaturation thresholds in exactly this temperature band. Egg-white proteins set across 62–80 °C; fish myosin denatures around 40–50 °C and the flesh is cooked through by 50–60 °C; chicken breast is safe and still juicy held around 65–70 °C. The danger of higher heat is the albumin/moisture squeeze: as muscle-fiber proteins (and the connective tissue around them) heat past about 60–65 °C, they contract and physically wring water out of the meat — which is why boiled chicken breast and fish are dry and tough while poached ones stay succulent. By holding below the temperature where this contraction turns violent, poaching cooks the protein just to set while retaining its moisture. The gentleness also keeps fragile foods physically intact: no churning to shred a fish fillet or shred a poached egg into wisps.

How it's done

Bring the poaching liquid to temperature and hold it there (a thermometer earns its keep here). Deep poaching fully submerges the food — a whole fish in court bouillon, eggs in acidulated water, a chicken breast in seasoned stock — for even, gentle cooking. Shallow poaching cooks the food partially submerged in a small amount of flavorful liquid in a covered pan, often in the oven, so the lower half poaches in liquid and the upper half cooks in the trapped steam; the liquid is then frequently reduced into a sauce (a cuisson). For eggs, a swirl of the water and a splash of vinegar (which speeds white coagulation) help the white gather around the yolk.

When to use it

For anything delicate and lean that you want tender and moist: eggs (poached, for eggs Benedict), fish and shellfish, chicken and turkey breast for salads and slicing, sausages (gently, so they don't split), fruit, and quenelles. Choose poaching over simmering/boiling whenever the food is lean, fragile, or prone to drying — and over sous-vide when you want simplicity and a flavored liquid that doubles as sauce.

What goes wrong

Letting the liquid creep to a simmer or boil (toughened, dry, or shredded results — the most common error by far). Unseasoned poaching liquid leaves bland food, since poaching seasons gently. Poaching eggs in water that's too hot or unswirled gives ragged whites; very fresh eggs poach far more neatly because their whites are tighter. Overcrowding drops the temperature unpredictably. Forgetting carryover — pull poached food a touch early.

Court bouillon, and why each component matters — A court bouillon ("short broth") is the classic aromatic poaching liquid for fish and shellfish, and each part does a job: water is the medium; acid (white wine, vinegar, or lemon) firms and brightens the fish flesh by lightly denaturing surface proteins and balances richness; aromatic vegetables (a mirepoix of onion, carrot, celery, often leek) lend savory depth; a bouquet garni (thyme, bay, parsley stems, peppercorns) layers herbal complexity; and salt seasons throughout. Unlike a stock, it's quick to make — simmered briefly to marry flavors, then used at poaching temperature. The result both cooks and seasons the fish, and can be strained and reduced into a sauce.

Regional & cultural variations

French cuisine is the great codifier of poaching: poché, the court bouillon, the shallow-poach-and-reduce cuisson method, quenelles poached to set. The British poached salmon with hollandaise is a banquet classic. Chinese 白切鸡 (bai qie ji), "white-cut chicken," poaches a whole bird gently (often by submerging, killing the heat, and steeping) for silky, just-set flesh — a benchmark of restraint in Cantonese cooking. Italian bollito misto, despite its name ("mixed boiled"), is really a gentle simmer/poach of mixed meats. Middle Eastern and South Asian cuisines poach fruits in spiced syrups (below).

Cultural & historical context

Poaching is a technique of refinement, associated historically with court and haute cooking where delicacy signaled sophistication — the gentle handling of expensive, perishable foods like fresh fish and the demonstration of a cook's control over heat. It rose to prominence in the codified French kitchen but the underlying restraint — cooking a chicken by steeping it off the heat — appears independently in Chinese culinary tradition as a mark of skill.

Reference notes

Child of Simmering; sibling to Coddling (its egg-specific extreme) and Poaching Fruit. Cross-link to court bouillon, to protein denaturation temperatures, to sous-vide (the modern precision-temperature descendant), to eggs Benedict and bai qie ji, and to the fish and poultry ingredient families. Contrast deep vs. shallow poaching directly in the next entry.