Surfactants in Milk Foam

Surfactants in milk are what allows a barista to produce a long lasting and glossy foam that is ideal for pouring latte art. A surfactant is a compound that lowers the surface tension between two substances.

To make a perfect latte, you need a foam that is long lasting and the best way to stop a bubble from bursting is to wrap it up in a surfactant. In milk foam chemistry, the name for this wrapping process is adsorption. In other words, where a substance adheres to another one and makes a film across it.

In coffee beverages, surfactants make bubbles less likely to burst because they reduce the surface tension between the milk and the air. The principal surfactant in milk foam is the protein β-lactoglobulin. This very elastic whey protein contributes to the production of extremely long-lasting foams. The key word when it comes to producing great latte foam is ‘elasticity’.

This video and dozens more like it forms part of Barista Hustle’s Milk Science course and certification. In this online course and certification we explore the science and mechanics of perfect milk foams. We examine the physics of milk steaming and how milk foams hold together.

If you enjoyed this video and want to learn more about how the right barista technique can help you produce ultra glossy foams, just follow the link below.