Science of why a tapped beer bottle foams

Discussion in 'Beer News' started by Ranbot, Oct 25, 2013.

  1. Ranbot

    Ranbot Nov 27, 2006 Pennsylvania

    Scientists in Madrid have figured how the oldest beer drinking prank works.

    http://physicsbuzz.physicscentral.com/2013/10/the-physics-is-clear-on-foamy-beer.html?

    Copied from link above:
    A team of three international scientists has explained the physics behind why beer in a bottle transforms into an overflowing mass of foam when the bottle receives a vertical tap on the mouth, as shown in the video. They will present their work and its applications outside of the bottle at the 66th Annual Meeting of the APS Division of Fluid Dynamics.



    The act is colloquially referred to as “beer tapping”: Someone hits a beer bottle on the head, often with the bottom of their own bottle, and within seconds the victim of the prank is left with a small amount of flat beer and a bottle dripping with foamy bubbles of carbon dioxide.

    Javier Rodríguez-Rodríguez, assistant professor at the Fluid Mechanics Group of Carlos III University of Madrid and lead author of an abstract about the research, and his colleagues were at a bar discussing the process behind this phenomenon when they realized they did not fully understand it. And according to their unsuccessful search for a solution online and through scientific databases, neither did anyone else.

    Through experimentation and computational simulations, they determined that the process starts with a series of waves and ends up fizzing all over the place.

    The initial tap to the bottle sends a shock wave through the glass to the bottle’s bottom. The energy from the wave transfers to the beer inside sending a second shock wave up toward the beer’s surface. It then bounces back again and keeps moving back and forth through the liquid until its energy dissipates.

    The wave motion and changing pressure knocks free tiny gas pockets trapped inside microscopic imperfections in the glass bottle. The pockets implode and create clouds of smaller bubbles from the dissolved carbon dioxide in the beer. Though these bubbles can quickly grow up to three times larger than their original size, that alone is not what makes the bottle overflow with foam.

    Individual plumes of bubbles float up through the beer, building up speed as they get bigger, until they burst out of the bottle’s top in a shower of foam. All of this happens within a matter of a few seconds and once the first tap is initiated is difficult to prevent.

    From the time of the tap to the first implosion of a single bubble, about one millisecond passes – too short for human reaction to kick in. However, you can keep the bubbles from growing and creating plumes by quickly plugging the bottle with your thumb until the carbon dioxide has a chance to dissolve back into the liquid – much like re-capping a soda bottle if it starts to spew everywhere upon opening. Although, that may take longer than you’re willing to wait.

    The team’s work is one piece of a larger ongoing research topic on carbonated beverages. In 2011, William Lee at the University of Limerick in Ireland, along with two colleagues, published a study on the “Bubble nucleation in stout beers”. And in 2005, Gérard Liger-Belair and two colleagues at the Laboratory of Oenology and Applied Chemistry in France published a study investigating bubble behavior in a glass of champagne.

    “We have observed such kind of uncontrolled bubbling production in sparkling wine and champagne. Uncorking the bottle may sometimes lead to such kind of phenomena,” said Liger-Belair who was not involved with Rodríguez's study.

    As Rodríguez and his colleagues delved deeper into the problem, they realized that the process that makes beer bottles foam might also have applications outside of bubbly beverages.

    “Recently, we have started working with an oil company,” Rodríguez said. “The dynamics of bubbles of a soluble gas, say carbon dioxide, in response to large amplitude pressure waves is of interest for the oil industry.”

    Another application might explain the physics behind underwater mud volcanoes.

    “There are natural phenomena called mud volcanoes in which an underwater volcano erupts, but instead of lava, it produces large quantities of mud. We have reasons to think that a mechanism very similar to the one occurring in beer bottles is behind these volcanoes,” Rodríguez said.
     
  2. pixieskid

    pixieskid Jun 4, 2009 Germany

    This is what scientists in Madrid care to study... :confused:
     
    ONovoMexicano likes this.
  3. Ranbot

    Ranbot Nov 27, 2006 Pennsylvania

    I know it's a little ridiculous, but...
    It's not always clear what scientific research is or isn't valuable until you do it.
     
    dvelcich, rlcoffey and jRocco2021 like this.
  4. rgordon

    rgordon Apr 26, 2012 North Carolina

    Damn. I'm glad that is finally understood. We will never know exactly how much this truly means.
     
    ONovoMexicano likes this.
  5. CraftBeerMe

    CraftBeerMe Nov 13, 2011 Virginia

    I'm glad that scientific discovery started at a bar...
     
    ONovoMexicano likes this.
  6. 1fJef

    1fJef May 4, 2013 Maryland

    Now if scientist could just figure out why scientist study "why tapped beer foams"-Id be happy
     
    Wylde likes this.
  7. 77black_ships

    77black_ships Dec 4, 2012 Belgium


    THIS. People always complain about research even things like Hadron Collider.
    People experimented 1500+ years with steam engines before coming up anything useful, people criticized them & their pointless toys. Lasers were considered completely pointless for decades etc. etc. etc.
     
  8. 4DAloveofSTOUT

    4DAloveofSTOUT Nov 28, 2008 Illinois
    Beer Trader

    I think its cool that they actually did a study on this "phenomenom". And in all honesty I find it very amusing, to the point of it gave me a really good laugh. OP this was a great read!
     
    ONovoMexicano and Ranbot like this.
  9. hopfenunmaltz

    hopfenunmaltz Jun 8, 2005 Michigan

    Some U of M Physics grad student came up with the idea for the bubble chamber, used for tracking sub-atomic particles, while drinking beer in a bar.
     
    cavedave, ONovoMexicano and NWer like this.
  10. OldhouseRecs

    OldhouseRecs Aug 3, 2012 North Carolina
    Beer Trader

    I just read a paper in some immunology journal and in the notes section they wrote that the idea for the paper came from discussions at the beer tent of a scientific conference. Alcohol brings out some great ideas.
     
  11. MostlyNorwegian

    MostlyNorwegian Feb 5, 2013 Illinois

    Some of the best ideas have come from answering the silliest of questions.
     
    jRocco2021 likes this.
  12. flying_dutchman

    flying_dutchman Oct 15, 2013 Ecuador

    how about instead of calling it a prank, which would imply that it is in some way funny, call it what it is... the biggest d*ck move ever and a crime against beer. :p

    flying_dutchman
     
  13. otispdriftwood

    otispdriftwood Dec 9, 2011 Colorado
    Beer Trader

    If this was something taught or shown in high school physics class, maybe I would have enjoyed it.
    As for those who think this was a needless waste of time, the article does point out that it may have other applications so it pays to read it through.
     
  14. Ranbot

    Ranbot Nov 27, 2006 Pennsylvania

    Haha...yeah fountains of beer in the classroom would definitely get the kids attention! However, wave propagation through different media and reflection off non-uniform surfaces is the stuff people earn their PhD's from, and probably way beyond high school teaching. Still, it could be a good way to introduce kids to wave forms and get them thinking about the larger implications of them.
     
  15. cavedave

    cavedave Mar 12, 2009 New York
    Beer Trader

    I could see this leading to many useful ideas. For instance, the first that comes to my mind, more creative and effective ways of exacting revenge.
     
  16. BruChef

    BruChef Nov 8, 2009 New York

    Until we figured out how fun it was to tease our pets and annoy our classroom teachers.
     
  • About Us

    Your go-to website for beer (since 1996), publishers of BeerAdvocate magazine (since 2006) and hosts of world-class beer events (since 2003). Respect Beer.
  • Return of the Belgian Beer Fest

    BeerAdvocate Brings its All-Belgian Fest to Portland, Maine on September 17, 2016. Tickets are on sale now.

    Learn More
  • Get the Mag

    Become a BeerAdvocate magazine print subscriber today.

    Subscribe