The Complete Handbook of Mayonnaise

Chapter 1: Understanding Mayonnaise

Mayonnaise is an emulsion. This single fact—understood and applied—explains nearly everything that matters about how mayonnaise behaves, why different products perform differently, and how to work with it reliably in any setting from a restaurant kitchen to a commercial production line.

An emulsion is a stable mixture of two substances that normally do not mix. Oil and water are the classic example: left alone in a jar, they separate into distinct layers. Mayonnaise forces them to stay together. It does this by introducing a third ingredient—the emulsifier—that has one end that attracts to oil and another end that attracts to water. In mayonnaise, that emulsifier is egg yolk. The egg yolk contains lecithin, a natural compound with exactly these two-faced properties. When you blend egg yolk with oil and water (along with acid and salt), the lecithin molecules arrange themselves at the boundary between the oil droplets and the surrounding water phase, holding the droplets in permanent suspension. The result is a thick, stable, pale yellow condiment.

This is not a trivial accomplishment. The oil content in standard mayonnaise is roughly 70 to 80 percent by weight. That means you are suspending an enormous amount of oil—far more oil than water—in a relatively small amount of emulsifier. The fact that this works at all, and that it stays stable for weeks or months in a refrigerator, is a direct result of the chemistry of emulsion formation and the properties of the egg yolk.

Why does