• Spain's news in English

Scientists unlock mystery of foaming beer

George Mills · 21 Jan 2014, 14:03

Published: 21 Jan 2014 14:03 GMT+01:00

It all started in a bar: that's how scientists from Madrid's Charles III University (UC3M) have described the beginnings of their year-long study.

The clashing of base of one beer bottle against the neck of a second bottle got researchers talking about why the beer frothed up.

When no one could provide a convincing reason, the team took their research back to the laboratory.

Using lasers, high-speed photography and bottles of the Spanish beer Mahou, the team — together with scientists at France's Jean le Rond D’Alembert Institute — discovered that knocking two bottles together caused a mini-explosion of carbon dioxide.

Usually carbon dioxide is released very slowly but when bottles collide, this happens in a fraction of a second.

This process involves three separate phases. First, the sudden vertical impact on the mouth of a beer bottle causes a compression wave that spreads through the glass towards the bottom. 

When this wave reaches the bottom of the bottle, it rebounds as an expansion wave that travels to free surface, where it bounces back again.

Next this chain reaction leads to the collapse of air pockets, or bubbles, in the beer, and this creates a cloud of tiny 'daughter' bubbles that expand much faster than their 'mothers' due to their smaller size. 

Lastly, those bubbles expand rapidly and race towards the top of the bottle because they are lighter than the beer that surrounds them. This explosive forces results in the froth.

"These clouds of foam look like the mushroom cloud of a nuclear explosion," Javier Rodríguez, a professor of UCSM's Department of Thermal Engineering and Fluids told Spanish science news agency SINC.

But the research isn't just a novelty.

Story continues below…

"One of the applications of this project is the prediction of the quantity of gas which is produced after the eruption of a volcano," explained Daniel Fuster from the Jean le Rond D’Alembert Institute.

The study could also help improve the design of ship propellers and anti-shock structures for buildings.

"This is one of the big advantages of basic research. You learn about physics on the cheap with systems as simple as a bottle of beer and later this helps you understand and try and solve large problems," said Rodríguez of the study.

George Mills (george.mills@thelocal.com)

Your comments about this article

Today's headlines
'Sulking Ronaldo has to live with being subbed': Zidane
Ronaldo celebrates a goal before he was substituted in the game against Las Palmas. Photo: Desiree Martin/AFP

Real Madrid coach Zinedine Zidane insisted Cristiano Ronaldo has to learn to live with being substituted after the Portuguese striker sulked off the field.

Basques and Galicians vote to unblock Spain's deadlock
Socialist leader Pedro Sanchez arrives in Galacia on Sunday for the vote. Photo: Miguel Riopa/AFP

Spain's Basque country and Galicia go to the polls Sunday in regional elections that may help unblock the long-lasting national political paralysis.

 Spanish cinema breaks taboo and talks ETA
A still from Justin Webster's documentary The End of ETA. Photo: The End of ETA

Documentaries on terror group ETA have been screened at San Sebastian film festival and met with applause, as the taboo fades.

 Spain's Socialists in crisis as political blockage takes toll
Pedro Sanchez has repeatedly said he won't support Rajoy. Photo: AFP

Spain's nine-month political paralysis is taking its toll on parties, and none more so than the Socialists who are facing a crisis, with talk of an imminent "coup" against leader Pedro Sanchez.

National anthem: Could Spain finally sing with one voice?
Spanish athletes have had to hum awkwardly for decades. Photo: AFP

Spain's parliament is being asked to consider a solution to one of nation's most enduring and embarrassing problems; what words to sing with the national anthem.

Spain's ten greatest parador hotels to visit this autumn
San Estevo parador in Galicia. Photo: rutea.es

Autumn is the perfect time to explore Spain's hidden corners and parador hopping is the best way to do it.

Spain's Basques go to polls as memories of violence fade
Basque regional president nationalist Inigo Urkullu (L) and Basque Nationalist Party-PNV's president Andoni Ortuzar (2nd L) in Bilbao. Photo: AFP

Could the results of the Basque elections have an impact on the national political deadlock?

Spanish parents call strike over too much homework
Do Spanish children get too much homework? Photo: AFP

Spanish parents have called for a “homework strike” to protest at the amount of extracurricular work they are expected to do with their children.

Family seeks funds for mother injured in Spanish bus crash
Julie Ann Fiegert was returning from a holiday of a lifetime. Photo: GoFundMe page

The family of an Australian woman left fighting for her life after a bus accident in Spain are trying to raise money for her medical expenses.

Second headless bison found at Spanish nature reserve

A mystery surrounding goings-on at a nature reserve in Spain deepened Thursday as a second European bison was found decapitated just days after staff discovered the headless body of the herd's dominant male.

Seven reasons why autumn is the very best season in Spain
Spanish study finds four types of personality. Which are you?
New search underway for civil war grave of poet Lorca
Bison found decapitated on Valencia nature reserve
Forgotten Voices: What Brits in Spain think about Brexit
One dead and 14 injured in blast at Spanish resort
Game of Thrones want extras 'with muscles' to film in Spain
Sponsored Article
Why Jordan is the ‘Different’ East
Thousands march in Madrid to push for bullfighting ban
Spanish team invents hands-free 'penis bidet'
In pics: Devastation caused by Costa Blanca wildfires
Pregnant woman in niqab attacked by two men in Spain
Spanish café offers cut-price coffee to those with manners
What's on in Spain: September 2016
'We drank from animal troughs to survive'
Forest fires threaten Costa Blanca resort of Jávea
Loyal dog mounts vigil at hospital doors for sick owner
Five reasons why Spain's Socialists won't back Rajoy
It's a girl! Rare giant panda cub born in Madrid zoo
La Tomatina: Everything you need to know about epic fiesta
Shocking video shows torture of young calf during fiesta
Police launch appeal for Costa Blanca hit and run driver
What political deadlock? Spain economy forges ahead
Eight reasons to spend your gap year exploring Spain
jobs available