Getting a pint with heads is a common cause of annoyance for pub-goers.
However, a new study suggests that the more foam a beer contains, the more flavorful the drink.
In laboratory tests, scientists in Japan found that a distinctive layer of foam makes the beer up to twice as aromatic and serves as a “tempting appetizer” to the beer’s overall flavor.
Aromatic substances are concentrated in the millions of individual bubbles in the creamy foam layer of the beer.
As each one collapses, flavor components are released into the atmosphere along with carbon dioxide, resulting in an enhanced taste perception.
Beer drinkers are often upset when they think their beer has too much foam – but new research suggests it enhances the taste
The study was led by researchers from Kyushu Sangyo University in Fukuoka and Japan’s Asahi Brewery.
“Beer foam plays a new role as a flavor carrier and specifically promotes the release of some characteristic aroma substances,” it says.
“Beer foam can promote the release of specific and attractive flavors that encourage beer drinking,” their article states.
“Foam acts as an efficient gas exchange surface, directing aroma to the drinker’s olfactory sensors.”
“It offers the drinker the first tempting impression of the taste quality, freshness, refreshment and wholesomeness of the beer.”
Whether fruity, malty or earthy, thanks to the olfactory receptors in the nose we can perceive the nuanced flavors of beer.
Meanwhile, the taste buds on our tongue recognize the “taste” of the beer – whether it is sweet, sour or bitter.
Typically, a beer contains hundreds of flavor compounds that are released through fermentation during the brewing process.
The scientists previously recorded aromas from the beer and frothed it using ultrasound waves (pictured).
Bettors may want to get their money’s worth by insisting on very little foam – but this may come at the expense of less flavor (file photo).
The science of beer foam
Beer is made through a fermentation process in which sugars in malt grains are converted into alcohol and carbon dioxide (CO2), the gas into beer bubbles.
Beer bubbles are important sensory elements of beer tasting because they carry flavors and aromas.
When you open a beer bottle, the sudden drop in pressure causes dissolved CO2 to escape from the beer.
Most of this CO2 escapes in bubbles that form on the sides and bottom of a glass, where microscopic cracks and imperfections serve as a starting point for the gas to accumulate.
When the CO2 reaches a critical volume at a nucleation point, a bubble separates from the glass and hurls itself toward the head of the beer.
Examples include isoamyl acetate, a compound that smells like banana or pear, and ethyl decanoate, which is said to have milk and fruit flavors.
For the study, the team used Japanese beer “purchased from the local Japanese market.”
Although three of the study authors were from Asahi, the brand of beer – and whether they used ale or lager – was not disclosed.
The beer was poured into a sealed glass cylinder, allowing flavors to escape only through a glass straw at the top, aided by an inward flow of nitrogen.
Aromas were monitored using a special mass spectrometer, an instrument that measures compounds in an air sample in real time.
The scientists previously recorded aromas from the beer and frothed it using ultrasound waves.
This ultrasound treatment mimicked the physical process a beer goes through when it is poured into a glass in a pub.
This allowed them to monitor aroma compounds inhaled through a drinker’s nose in both a foamed and flat beer.
Overall, the team found that the “concentration proportion of aroma components” was 1.3 to 1.9 times higher in foamed beer compared to beer without foam.
They also found evidence that the more “hydrophobic” or water-repellent a flavoring agent is, the more likely it is to be concentrated in the foam.
Aromas were monitored using a special mass spectrometer, an instrument that measures compounds in an air sample in real time
Researchers also say beer foam acts as a “lid” to prevent gaseous carbon dioxide from escaping and keep the drink fizzy
However, they admit that the lack of foam highlights hydrophilic flavors like malt and caramel in the actual liquid.
‘[We] “clarified a novel role for beer foam as a flavor carrier,” says their article. Published in Journal of the American Society of Brewing Chemists.
“Beer foam can promote the release of specific and attractive flavors that encourage beer drinking.”
The researchers cite a number of other benefits of beer foam, including acting as a “lid” that prevents gaseous carbon dioxide from escaping and keeps the drink fizzy.
“Creamy foam creates a unique mouthfeel on the upper lip when drinking and therefore probably helps make beer taste delicious,” they add.
They also say that the contrast between the foam and the color of the liquid is “a symbol of the beauty of the beer.”
Ireland is the true home of BEER! Scientists discover the elusive ancestor of the yeast used for lager in a Dublin forest
Scientists have discovered the ancestor of the type of yeast necessary for making lager – in Ireland.
Saccharomyces eubayanus is a little-known yeast species that gave rise to the yeast Saccharomyces pastorianus used today for brewing lager.
S. eubayanus was first found in the Patagonian Andes in 2011, but experts have found it in the wild for the first time in Europe, in the Dublin Forest area.
They now want to create a new beer using the rare “mother” yeast S. eubayanus that could create new flavor profiles never tasted before.
Yeast is one of the four main ingredients for making beer, along with water, grains and hops.