ETH Zurich researchers uncover the secret to lasting beer foam

Researchers at ETH Zurich, led by Professor Jan Vermant, have uncovered the complex physics behind the long-lasting foam on certain beers, particularly Belgian ales. Their seven-year study revealed that foam stability varies significantly among beer styles: Tripels exhibit the most durable foam, followed by Dubbels, while Singels have less stable heads. The team also found that some Swiss lagers can rival Belgian ales in foam longevity, though the underlying mechanisms differ. Contrary to previous beliefs that protein layers alone determine foam stability, the researchers showed that factors like surface viscoelasticity and the specific arrangement of proteins around bubbles play crucial roles, varying by beer type. In Belgian Singel beers, proteins behave like particles forming a stabilizing suspension, whereas in Dubbels, proteins create a net-like membrane that strengthens bubbles. For lagers, the elasticity and rigidity of the bubble film are key. Beyond brewing, these insights have broader applications, such as improving foam management in lubricants for electric vehicles and developing sustainable surf