Emulsions

Emulsions are molecular suspensions that can take one of two forms: fat surrounded by water or water surrounded by fat. A vinaigrette is a fat-in-water emulsion resulting in a translucent appearance and a silky mouth-feel; mayonnaise is a water-in-fat emulsion, resulting in an opaque appearance and a creamy mouth-feel. Fat-in-water emulsions are made by simple agitation, if the molecules fall out of suspension they can be re-emulsified by simply agitating again. Water-in-fat emulsions are more challenging because they require an additional emulsifier, like egg yolk, and if you’re not careful, your ingredients can fall out of suspension, leaving you with just some eggy, watery oil.