ETH: Secret of beer foam stability revealed
Keystone-SDA
After seven years of research, specialists at the Swiss Federal Institute of Technology Zurich (ETHZ) have unveiled the secret of beer foam stability.
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The results were published in the journal Physics of Fluids.
In their study, the team led by Jan Vermant showed that Belgian triple-fermented beers have the strongest foam, while bottom-fermented lagers are characterised by the rapid dissolution of their foam.
Until now, it was believed that it was the barley malt proteins, responsible for viscosity and surface tension, that determined the firmness of the foam. The study shows, however, that this only applies to lagers, where a higher protein content ensures greater stability.
In multi-fermented beers, however, another physical phenomenon comes into play: the Marangoni effect, which points to surface flows generated by variations in tension that help to strengthen the bubbles.
A key role is played by the LTP1 protein, which changes structure at different fermentation stages to form membranes or fragments that further stabilise the foam. The research was conducted in collaboration with one of the world’s largest breweries, which aims to improve the quality of its products. “We now know the mechanisms precisely and can support the industry,” said Vermant.
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Translated from Italian by DeepL/mga
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