Emulsions

An emulsion is a uniform mixture of two substances that are normally unmixable. A familiar example of an emulsion in the kitchen is mayonnaise, which is a mixture of oil and vinegar. Most of the emulsions we are concerned with in the kitchen are mixtures of fat and water. However, emulsions can be mixtures of any two substances. For example, when we cream together butter and sugar until light and fluffy, we create an emulsion of fat and air.

In an emulsion of two liquids, one of the liquids is said to be in suspension in the other. This means that one of the liquids is broken into tiny droplets and mixed evenly throughout the other liquid. The liquid that is broken into droplets is called the dispersed phase, while the liquid it is mixed in is called the continuous phase (see Figures 6.1 and 6.2).