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."

21 of 55 comments (clear)

  1. Now that I know the theory by cristiroma · · Score: 5, Funny

    Allow me to practice ...

  2. 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

    1. Re:late to the party by NatasRevol · · Score: 5, Funny

      Yeah, but the new research had to make sure it wasn't the Coriolis force!

      --
      There are two types of people in the world: Those who crave closure
    2. Re:late to the party by Geek70 · · Score: 3, Funny

      The underlying principle in science is to form a model and then test for confirmation or error. Clearly these dedicated professionals were testing in the name of science in case other forces were involved! In fact, I should do my part and run some tests of my own. I might also test some principles regarding gravity while I'm at it....

    3. Re:late to the party by camperdave · · Score: 2

      It's easy to see why this would be so in Australia. They're on the bottom of the world, and bubbles go up.

      --
      When our name is on the back of your car, we're behind you all the way!
  3. 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)
  4. Is it replicatable? by chill · · Score: 2, Funny

    I believe this study will end up receiving more than its fair share of replication and confirmation studies.

    In fact, I can see several follow-up studies on if (and possibly why) this is specific to stout. How about a nice lager "control group" for the lads at table 3?

    --
    Learning HOW to think is more important than learning WHAT to think.
    1. 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.

    2. 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

    3. Re:Is it replicatable? by Mindcontrolled · · Score: 2

      Fortunately, Budweiser is not representative. Lager comprises the Bavarian pale lagers, including Maerzen, i.e. the Oktoberfest beer. Heck, bock beer is a subcategory of Lager - not exactly incredible weak there...

      --
      Ubi solitudinem faciunt, pacem appellant.
  5. Mythbusters by goodmanj · · Score: 4, Interesting

    Mythbusters (accidentally) did it first.

    http://www.youtube.com/watch?v=q4YeP7e0tPE&t=190

  6. party pooper by G3ckoG33k · · Score: 4, Funny

    That's an astout observation!

    Hence, no stout for you, mister. ;)

    1. Re:party pooper by Hognoxious · · Score: 3, Funny

      You sound bitter.

      --
      Confucius say, "Find worm in apple - bad. Find half a worm - worse."
  7. I thought... by bobbied · · Score: 2

    I thought it was just a side effect of drinking the stuff.... Like the floor smacking me in the face... Hey, bar-keep! Keep'm coming until the bubbles start sinking...

    --
    "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
  8. DO NOT by Fned · · Score: 4, Funny

    ...I repeat DO NOT touch a pint glass and an anti-pint glass during a toast.

    That is all.

    1. Re:DO NOT by Eli+Gottlieb · · Score: 2

      They'll annihilate each other, leaving you with nothing but a piece of bread.

    2. Re:DO NOT by idontgno · · Score: 3, Funny

      Only after a rather stout explosion, though.

      --
      Welcome to the Panopticon. Used to be a prison, now it's your home.
  9. Location, location, location by Anonymous Coward · · Score: 2, Funny

    Guiness is brewed in Ireland. The bubbles are made in Australia. When the can is opened the bubbles attempt to to up, but they are from Australia so they head the wrong way. Another pint of your finest, barkeep!

    1. Re:Location, location, location by digitig · · Score: 2

      The bubbles are embarrassed at being full of nitrogen instead of carbon dioxide (as beer bubbles should be) and are trying to hide?

      --
      Quidnam Latine loqui modo coepi?
  10. Negative ninety-nine bottles of beer on the wall. by neoshroom · · Score: 5, Funny

    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

    Just don't drink too many anti-pints of beer. I tried it once and woke up with a hell of a hangunder.

    --
    Big apple, new Yorik, undig it, something's unrotting in Edenmark.
  11. Re:Math by idontgno · · Score: 3, Funny

    Science. It works, bitches.

    --
    Welcome to the Panopticon. Used to be a prison, now it's your home.