Two preparations that exist at opposite ends of the Maillard browning scale for butter — and that demonstrate, together, the full flavour arc that butter undergoes as heat transforms its milk solids. Beurre noisette (hazelnut butter — named for its colour, not its flavour): butter cooked until the milk solids turn a deep gold and the smell is of hazelnuts and caramel. Beurre noir (black butter): the same process continued past the hazelnut stage to a dark, almost-burnt colour, then deacidified with capers and vinegar. Both are sauces in themselves — immediate preparations, finished in seconds, served at the moment of completion.
**Beurre noisette:** - Unsalted butter in a small, light-coloured saucepan (to track colour accurately). - Medium heat. The butter melts, foams (water evaporating), the foam subsides, and the milk solids at the base of the pan begin to colour. - The correct colour: deep gold — the exact colour of a blanched hazelnut. - Remove from heat immediately at correct colour. Add a squeeze of lemon juice — the acid stops the cooking. - Pour immediately over the dish or pass through a sieve. **Beurre noir:** - The same process continued until the solids are dark brown — one stage past noisette, not actually black (black = burnt = bitter = wrong). - Off heat: add a tablespoon of red wine vinegar or sherry vinegar — it produces a violent, fragrant sizzle. - Add drained capers. - Pour immediately. - Classical application: skate (raie au beurre noir), brain preparations, poached eggs. Decisive moment: Colour management for both — and the speed of the deceleration. Butter at the correct noisette colour is 10 seconds from correct to burnt in a hot pan. Once at the correct colour: remove from heat immediately, add the acid (lemon juice for noisette, vinegar for noir). The acid stops the Maillard reaction by pH change. Without the acid: the residual heat of the pan continues the browning for 30 seconds after removal from the heat. Sensory tests: **Sight:** Light-coloured pan is not a preference — it is a requirement. The milk solids colour from white to gold to brown in the base of the pan. In a dark pan, this progression is invisible until it is too late. **Smell:** Beurre noisette at the correct point smells of hazelnuts, caramel, and a faint toasty note. One additional 10 seconds: the smell tips from pleasant-nutty to sharp-burnt. Trust your nose.
Jacques Pépin's Complete Techniques