Shelf · Sauces & emulsions · Low heat
Mounting with butter
Whisking cold butter, a cube at a time, into a warm reduction off the heat, so the sauce thickens and turns glossy.
- The temperature band
- The liquid · 60 to 70 °C
Why it works
Cold butter melts slowly enough that its fat disperses into droplets rather than pooling, and the milk solids it carries hold those droplets suspended. That suspension is what makes the sauce cling to food instead of running off it.
The tell
The sauce thickens slightly, turns opaque and satiny, and coats a spoon in an even film with no oily rim at the edge.
- Split
- Coming together
- One sauce
How it fails
Above about 70 °C the emulsion breaks and the butter separates into a greasy slick — take the pan off the heat first, and never let it return to a simmer afterwards. A broken sauce comes back: whisk it, off heat, into a spoonful of fresh cold cream or a fresh reduction.
In the app, the card opens on the recipe step that names it, with the tell drawn.
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