Mount

To mount a sauce (French: monter au beurre) is to incorporate small pieces of cold butter into a warm sauce, usually off the heat or over very gentle heat, to add richness, gloss and a smoother texture. The butter is whisked or swirled into the liquid so that its fat disperses into a fine emulsion.

How to mount a sauce with butter

1. Reduce and season the sauce before adding the butter.
2. Remove the pan from direct heat or lower the heat substantially.
3. Add small pieces of cold butter gradually while whisking or swirling the pan.
4. Continue until the sauce becomes glossy and lightly thickened.
5. Serve promptly; avoid boiling after mounting.

Common applications

Mounting is used to finish pan sauces, fish sauces, reductions and some vegetable preparations. It is also associated with finishing beurre blanc, although beurre blanc is a butter emulsion built through its own specific method.

What can go wrong?

Excessive heat can cause the butter emulsion to separate and release fat. Adding too much butter at once can also make it difficult to create a smooth, stable finish.

Chef’s tip: Use cold butter cut into small cubes and incorporate it gradually. Once mounted, keep the sauce warm but do not let it boil.

Key distinction: Mounting with butter is a finishing technique that enriches and emulsifies a sauce; it is not the same as thickening with a roux or starch.