Butter Mounting

Butter mounting (French: monter au beurre) is the technique of whisking cold pieces of butter into a warm sauce just before service to create a glossy, lightly thickened emulsion. The butter adds richness, rounds the flavour and gives the sauce a smooth finish.

How to mount a sauce with butter

1. Prepare and reduce the sauce to the required flavour and consistency before adding butter.
2. Lower the heat or remove the pan from direct heat.
3. Whisk in small pieces of cold butter gradually, allowing each addition to emulsify before adding the next.
4. Keep the sauce warm but avoid boiling after the butter has been incorporated.
5. Serve promptly for the best texture and sheen.

Where chefs use butter mounting

The technique is common for finishing pan sauces, jus and reductions. It is related to the emulsification used in beurre blanc, although beurre blanc is built around an acid-and-wine reduction with a larger proportion of butter.

Why temperature matters

The sauce must be warm enough to melt and disperse the butter, but excessive heat can break the emulsion and cause the fat to separate. If the sauce is too hot, cool it briefly before whisking in the butter.

Example: reduce red wine and stock in a pan after searing a steak, then whisk in cold butter off the heat for a glossy finishing sauce.

Chef’s tip: Mount the sauce close to service and avoid holding it hot for long periods. Butter mounting is a finishing technique, not a substitute for reducing and balancing the sauce beforehand.

Key distinction: Butter mounting finishes a prepared sauce by emulsifying cold butter into it; it is not the same as thickening with roux or beurre manié.