Rescuing a broken sauce
Hollandaise and mayonnaise hold tiny fat droplets in water, with the lecithin in egg yolk keeping the droplets apart. Too much heat tightens the yolk proteins, and adding fat too fast overwhelms them. Either way the sauce separates.
Rebuild the emulsion
Put a fresh egg yolk, or a spoonful of warm water, in a clean bowl. Whisk it smooth, then drizzle the broken sauce in a little at a time while whisking hard. This rebuilds the emulsion from scratch.
Test yourself
Questions from the interactive lesson, with the answer and the why.
A hollandaise turns greasy and curdled-looking over the heat. Why?
It got too hot and the yolk proteins tightened. Tight proteins squeeze out the fat, and the sauce splits.
True or false: A broken hollandaise can't be rescued and must be thrown out.
False. A fresh yolk or a little water lets you rebuild the emulsion from the broken sauce.
What went wrong? You pour the whole broken sauce into a fresh yolk in one go and whisk hard. It stays split.
The fat went in too fast for the yolk to coat it. Droplets need time to be coated, so feed it in slowly.
Fill the blank: To stop mayonnaise breaking, add the oil ___ while whisking hard.
To stop mayonnaise breaking, add the oil slowly while whisking hard. Slow addition gives lecithin time to coat each droplet.
Why can a spoonful of warm water rescue a split sauce?
It lets the whisk break the fat into fresh droplets. More liquid gives the emulsifier room to rebuild the emulsion.