Slashdot Mirror

← Back to Stories (view on slashdot.org)

Mathematicians Show Why Bubbles Sink in Nitrogen-Infused Stouts

Posted by Unknown on from the don't-get-caught-in-the-beer-vortex dept.

SicariusMan writes "The age old question: do Guinness and other stouts' bubbles really sink, or is it an optical illusion? Well, some mathematicians have figured it out." Full paper via arXiv; From the article: "To analyze the effect of different glass shapes, the mathematicians modeled Guinness beer containing randomly distributed bubbles in both a pint glass and an anti-pint glass (i.e., an upside-down pint). An elongated swirling vortex forms in both glasses, but in the anti-pint glass the vortex rotates in the opposite direction, causing an upward flow of fluid and bubbles near the wall of the glass."

4 of 55 comments (clear)

  1. late to the party by Anonymous Coward · · Score: 5, Informative

    The Australians figured it out 12 years ago

    http://science.slashdot.org/story/00/01/11/2156213/why-bubbles-in-guinness-fall

  2. American fluid dynamicists did it first! by Colonel+Korn · · Score: 4, Informative

    Twelve years ago an almost identical paper was on the office wall of a chemical engineering professor I had in college. I'm mostly kidding with my subject line - I expect there's novelty in the new paper and just want to point out that this has been used as a model system (probably many times) before now.

    --
    "I zero-index my hamsters" - Willtor (147206)
  3. Re:Is it replicatable? by krotkruton · · Score: 3, Informative

    It's not because they're stouts, it's because nitrogen is used in making certain stouts (in this case, the title was better than the summary). Non-nitrogen stouts won't work. For example, Left Hand Brewery has a Milk Stout and a Milk Stout Nitro; only the Nitro has the cascade. Unless you find a nitrogen lager, there's really no experiment to be had.

  4. Re:Is it replicatable? by BattleApple · · Score: 3, Informative

    Boddington's pub ale uses nitrogen, and it exhibits the same behaviour as Guinness.. it's interesting to see the effect in a clear fluid