Building an emulsion · The World Table

On the Path of Study: Semester 9: Seafood Mastery

From the Lexicon, Emulsions

Fat and water convinced to coexist as droplets, held by an emulsifier (egg-yolk lecithin, mustard, starch, or sheer agitation): the physics behind mayonnaise, hollandaise, vinaigrette, beurre blanc, aioli, and glossy pan sauces. The universal method: add fat SLOWLY to the water phase while shearing hard; the universal failure: too fast, too hot, or too cold, and it 'breaks' into grease. The universal rescue: start fresh with a new yolk (or a spoon of water/mustard) and whisk the broken sauce INTO it. Pasta's starchy water emulsifying oil and butter into clinging sauce is the same trick; Italian kitchens just never named it.

Read it in the Lexicon →

How to tell it is going right

It visibly thickens as the fat goes in, heavier and more opaque than either part was alone, which is the emulsion announcing itself.
At no point is there a pool of free fat sitting ahead of the work: fat went in no faster than it disappeared into the body.
Glossy and homogeneous, with no slick floating on top and no visible droplets standing apart in it.
It clings: coating what it is put on and holding a line, rather than running off and splitting into a puddle at the plate’s edge.
It survives standing: minutes later there is no ring of weeping liquid underneath and no film of fat breaking out on the surface.

Where it goes wrong The fat went in faster than the shear could break it up, or the temperature drifted out of the range the method needs: it breaks into grease over a thin liquid, and whisking the broken thing harder does nothing. The rescue is a fresh base, with the broken sauce worked into it slowly, as if it were the fat.

A chosen film Make Homemade Mayonnaise with Master Chef Jacques Pépin Jacques Pépin Foundation Watch for: The moment the sauce seizes into thickness: watch how slowly the oil goes in at the start and how the stream can widen once the emulsion has taken, which is the single judgement that separates mayonnaise from a broken puddle of yolk and oil.