WeeklyDelight
Cooking guide

How to Rescue a Split Sauce

A split sauce has not failed for good. The fat and the liquid have separated, and in most cases they can be brought back together.

Mayonnaise, aioli, hollandaise, béarnaise and beurre blanc are emulsions: tiny droplets of fat held apart in a small amount of liquid, with egg yolk or reduced butter solids keeping them suspended. They split when the droplets merge, which happens for two common reasons: the fat went in too fast for the yolk to take it, or the temperature went wrong, too hot for an egg sauce (the yolk sets and stops working) or too cold for a butter one.

The rescue

  • Take the pan off the heat at once if it is a warm sauce.
  • Put a fresh egg yolk in a clean bowl. For a sauce served without further cooking, use a pasteurised yolk (British Lion-stamped in the UK), as the recipes here do.
  • Whisk the split sauce into the new yolk a drop at a time, as slowly as you added the oil or butter the first time. Once it thickens, you can add the rest a little faster.
  • Do not add the new yolk to the split sauce; the order matters, because the yolk has to be in charge of a small amount of fat at the start.
  • If an egg sauce has scrambled into curds, the yolk has set; a fresh yolk may help, but a sauce with visible cooked egg is better started again.

Several cooks also suggest whisking a teaspoon of water into a sauce that is just starting to look greasy, before it fully splits. That is a common kitchen remedy rather than something this site has tested.

Stopping it happening

  • Start the oil or butter literally drop by drop, then a thin stream once the sauce thickens.
  • Keep hollandaise and béarnaise warm, not hot: over barely simmering water, never boiling.
  • Have the yolks and oil at room temperature for mayonnaise.
  • For carbonara, take the pan off the heat before the egg goes in and loosen with pasta water; the aim is a sauce, not scrambled egg.

Recipes that use this