While preparing the emulsions, often conflicting natural components have to be combined into a consistent and stable blend of ingredients in two or more phases. Each component (esters, solvents, polar oils and fats, water, etc.) has its own properties which are sometimes conflicting to one another and usually do not mix or blend with one another. To make the two components compatible, emulsifiers are used. Emulsifiers act as an interface between all the conflicting components in a formula.
An emulsifier is a molecule with one oil-friendly (lipophilic) end and one water-friendly (hydrophilic) end. In this way droplets of oil are surrounded by the emulsifier molecule, with the oil core hidden by the water-friendly tails of the emulsifier. Depending on the emulsifier's properties and chemistry, the reverse will also be true. A classic natural emulsion is milk, which is a complex mixture of fat suspended in an aqueous solution. This would be the curds and whey from the fairy tale where curds are the solid oil part and whey is the liquid water part.