Emulsion
An emulsion is a stable mixture of two liquids that don't normally mix, usually oil and water, held together by an emulsifier.
Origin
Emulsions are behind vinaigrette, mayonnaise and hollandaise. Egg yolk contains lecithin and acts as an emulsifier; mustard can also bind dressings. The result is a creamy, glossy texture that doesn't separate straight away.
How to
Work the oil in drop by drop at first, then in a thin stream, whisking constantly. Make sure the ingredients are at a similar temperature. This spreads the fat into fine droplets.
Common mistake
Add the fat too quickly and the emulsion breaks and separates. If that happens, slowly whisk the broken mixture into a fresh egg yolk or a teaspoon of water.
Related recipes
Salsiccia Pasta with Fennel, Lemon and White Wine, Romana parmesan croutons and chicken? - The caesar salad
Related terms
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