This is absolutely vital research

 

Can't pass this article up;  researchers worked for years to figure out why the head (foam) on top of beers lasts longer for some kinds of beers -- particularly higher alcohol content Belgian Tripel beers.

OK, that sounds frivolous, maybe. But a good beer is much appreciated by discerning beer drinkers, and the foam is part of both the entertainment and the enjoyment. And underlying the seeming frivolity is some really fascinating chemistry and physics, which could be useful for other, perhaps more important, processes and phenomena.

So let's dive into the glass or mug, as the case may be.

Why Belgian Beers Lasts So Long
The Belgian researcher and his team put seven years of work into the subject.  (And I hope they enjoyed it, too.)

"In this study, the materials scientists showed that when it comes to the Belgian ales studied, “Tripel” beers have the most stable foam, followed by “Dubbel” beers. The head is least stable in beers without intense fermentation and with the lowest alcohol content (“Singel”)."

But WHY? you are certainly asking.

"In lager beers, surface viscoelasticity is the decisive factor. This is influenced by the proteins present in the beer, as well as their denaturation: the more proteins the beer contains, the more rigid the film around the bubbles becomes and the more stable the foam will be.

The situation is different with “Tripel”-style beers, where surface viscoelasticity is actually minimal. Stability is achieved through so-called Marangoni stresses – forces that arise from differences in surface tension."

(Really cool video demonstrating Marangoni effects)

So you can read the article or the paper (reference below).

Reference: Chatzigiannakis E, Alicke A, Le Bars L, et al. The hidden subtlety of beer foam stability: A blueprint for advanced foam formulations. Phys Fluids. 2025. doi: 10.1063/5.0274943.

I'll finish with Nicola Cavanis and beer.

Nicola:

Beer (a Belgian Tripel):