Definition - What does Surfactant mean?
Surfactants are complex organic molecules consisting of both hydrophilic (soluble in water) and hydrophobic (insoluble in water, but soluble in fats and lipids) groups. These molecules can decrease the surface tension of liquids and increase the rate at which the liquids spread. The presence of surfactants in the surface of a wine has two major effects; it limits the production of aromatic compounds and determines the rate of production, quantity produced and stability of mousse.
WineFrog explains Surfactant
The presence of protein and glycoprotein in the surface of wine leads to the production of surfactants. Various aromatic compounds which give odor to wine are present in the bubbles in the surface of wine. These compounds give wines their individual fragrances and help distinguish wines, however, accumulation of surfactants can prevent the release of aromatic compounds and decrease the aroma of wine.
Surfactants are primarily composed of lipids and protein. They occur naturally in the lungs and are vital in stabilizing the alveoli, but they can also be synthesized artificially. Surfactants are able to form bonds with both water and heavier liquids, like oil, and fat enables them to form similar transition mediums between various liquids as well.
The nature of surfactant present in wine also determines the production and durability of mousse or foam. Surfactants with higher quantity of ester can increase the mentioned characteristics of mousse while the higher amount of free fatty acid can have a decreasing effect.