- Professor Abbott’s Five Foam Factors teach us that the conditions for producing superior latte foam are very specific.
- The two main protein types in milk are caseins and whey proteins.
- Casein acts as an emulsifier for homogenised fats.
- Whey protein is the principal surfactant in milk.
- Surfactants make milk foams more elastic by reducing the surface tension between the air and the bubble film known as the lamella.
Adsorption The process through which atoms, ions, or molecules spread across the surface of a material to form a film
Aeration level The proportional increase in the volume of milk expressed as a percentage after the introduction of entrained air; volume gains added to the milk as a result of condensed H20 also contribute to this volume increase.
Amphiphilic Quality of a molecule which has hydrophobic and hydrophilic components
Closed-cell foam A foam wherein each cell occupies a distinctly separate pocket, surrounded by solid material
Drainage The separation of the liquid and air fractions of a foam, promoted by gravity and capillary action
Hydrolysis The chemical breakdown of a molecule caused by an interaction with water
Hydrophilic The tendency of a substance to mix with or dissolve into water
Hydrophobic The tendency of a substance to repel or resist dissolution with water
Ionics Compounds that are joined together by ionic bonding and are soluble in water; non-ionics are compounds formed of covalent bonds that can’t be dissolved in water.
Lamella The film coating the outside of a bubble
Liquid fraction The proportion of the total volume of a foam which is occupied by fluid