A glass of beer isn't complete without a frothy head of foam, caused by bubbles of carbon dioxide rising to the surface.
Unlike the bubbles in most other carbonated drinks, each beer bubble is coated in proteins, forming a protective film that increases the bubble's lifespan.
These proteins come from the malted grains used in the brewing process.
Researchers have recently demonstrated that the proteins in beers with longer fermentation times, such as many Belgian ales, are especially effective at stabilising bubbles, resulting in longer-lasting foam.
A beer with a higher protein content, such as wheat beer, is also likely to have a thicker and more stable head. Cheers!
This article is an answer to the question (asked by Stan Parker, Plymouth) ‘Why do some beer foams last so long?’
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