Research reveals why single fermentation beers sometimes lack the thick, stable foam of other pub favourites
A flat pint of beer with no head is a common gripe among pub-goers. And while the bar staff’s pint-pulling technique is often assumed to be the cause, scientists have discovered that the stability of beer foam is also highly dependent on the chemical makeup of the brew.
Triple fermented beers have the most stable foams, the study found, while the froth created by single fermentation beers, including lagers, are inherently more likely to collapse before you have time to take the first sip.
“We now know the mechanism exactly and are able to help the brewery improve the foam of their beers,” said Prof Jan Vermant, a chemical engineer at ETH Zurich, who led the study.
The research began as a “typical Friday afternoon project”, Vermant said. “We decided to study beer and found this really rich physics going on.”
