Stock — The Foundation of Professional Cooking
Stock is bones, mirepoix, water, and time — the clear, deeply flavoured liquid that underpins every sauce, soup, braise, and risotto in professional cooking. It is not broth (which includes meat and is seasoned for drinking) and it is not bone broth (a modern marketing term for long-cooked stock). Stock is unseasoned, gelatin-rich liquid designed to be a building block, not a finished product. White stock: raw bones, cold water start, 4–6 hours for chicken (Gallus gallus domesticus), 8–12 hours for veal or beef. Brown stock: bones roasted at 220°C (425°F) until deeply caramelised, mirepoix roasted alongside, then simmered 8–12 hours. The cold-water start is where the dish lives or dies. Proteins in the bones are soluble in cold water; as the temperature rises slowly, these proteins denature, coagulate, and float to the surface as grey scum. Starting with cold water and bringing it to a simmer gradually extracts the maximum amount of protein and gives you the opportunity to skim it away, producing a clear stock. Dumping bones into boiling water shocks the proteins, which fragment into tiny particles that remain suspended — producing a permanently cloudy, muddy-tasting stock. Quality hierarchy for bones: 1) Veal bones (especially knuckle joints) — the gold standard. Young animals have more collagen than older ones, and veal knuckles are almost pure collagen. A properly made veal stock gels solid at refrigerator temperature, a quality called body that no other bone matches. 2) Chicken carcasses and feet — feet are collagen-rich and produce excellent body. Carcasses from roasted chickens give darker, more flavourful stock. 3) Beef marrow bones and oxtail — richer and more assertive than veal, used for brown stock and demi-glace. 4) Fish bones (sole, turbot, halibut — flat white fish only) — 20–25 minutes maximum. Salmon and oily fish bones produce bitter, fishy stock. The mirepoix (2 parts onion, 1 part carrot, 1 part celery) goes in during the last 45–60 minutes for white stock, or is roasted and added at the beginning for brown. Adding vegetables at the start of a 12-hour simmer extracts their flavour in the first hour and their bitterness for the remaining eleven. Skimming: every 20–30 minutes during the first 2 hours, then hourly. Use a ladle, not a spoon. Skim from the edges where the scum accumulates. Never stir the stock — stirring emulsifies the fat and breaks up the scum, reincorporating impurities. The simmer should show lazy bubbles breaking the surface every few seconds, never a rolling boil. Boiling agitates the fat into permanent emulsion, producing cloudy stock.