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Mathematicians Show Why Bubbles Sink in Nitrogen-Infused Stouts

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."

55 comments

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

    Allow me to practice ...

    1. Re:Now that I know the theory by Anonymous Coward · · Score: 0

      I've tried drinking Guinness upside-down. Fun but messy.

      Even more fun and more messy was the Guinness on the train returning from Belfast to Dublin.

      With the train underway, an accomplice pours drink from out of window at beginning of the carriage, while we took turns sticking our heads out of a window a few meters further down. Not much beer drunk, and had to be quick to avoid the trees.

      The joys of junior cup rugby (15 years old), and now we learn it was all in the name of science.

      I'll drink to that.

  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 _anomaly_ · · Score: 1

      So? If you were in a position to justify such an experiment, wouldn't you do it, without any regard to prior studies? Count me as one vote for the "best experiment subject of the year" award.

      --
      "I have no special gift, I am only passionately curious." - Albert Einstein
    3. Re:late to the party by buchner.johannes · · Score: 1

      Link (in there) doesn't work anymore, and I can't find it.

      --
      NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
    4. Re:late to the party by ae1294 · · Score: 1

      The Australians figured it out 12 years ago

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

      Yes but the math starts getting real dense midway in just about the time the author starts using 'yourmothersawhore' as a delta function. The last few pages seem to be completely unrelated work on chaos theory but I'm not sure that was intentional.

    5. 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....

    6. 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!
    7. Re:late to the party by Anonymous Coward · · Score: 0

      The work was done by Clive A.J. Fletcher, University of New South Wales, Centre for Advanced Numerical Computation in Engineering and Science (CANCES)

    8. Re:late to the party by Anonymous Coward · · Score: 0

      Did anyone else just feel very old? A link to a 12 year old story on slashdot?

  3. Re:Wow! Such a thing! Allow me to violate... by Anonymous Coward · · Score: 1, Insightful

    Violate THIS!

    C'mon, Slashdot, is it that hard to outright block messages that contain specific URLs?

  4. 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)
    1. Re:American fluid dynamicists did it first! by r_batty_00 · · Score: 1

      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 believe you are referring to Md Nurul Hasan Khan. In 1999 he published a paper proving Guinness bubbles fall. As far as I know he was the first.

      http://www.smh.com.au/articles/2004/03/19/1079199418340.html

  5. 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 Anonymous Coward · · Score: 0

      +1 for Left Hand Milk Stout

      -Cheers

    4. Re:Is it replicatable? by treeves · · Score: 1

      Next study: helium-3 infused stouts vs. non-helium-3 infused stouts.

      --
      ...the future crusty old bastards are already drinking the Kool-Aid.
    5. Re:Is it replicatable? by zippthorne · · Score: 1

      the category of ale encompasses many beers, including stouts like Guinness.

      It does not, however, encompass lager, which if Budweiser is representative, is a category of beer whose terrible flavor is only mitigated by its incredible weakness.

      --
      Can you be Even More Awesome?!
    6. 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.
    7. Re:Is it replicatable? by BattleApple · · Score: 1

      An ale is still not always a stout. If a stout is basically an ale made with roasted malt, the question could be it's something to do with the malt and not the yeast.

      Bud is disgustingly weak as far as flavor, but higher alcohol content than I thought. (5%abv) I always thought it was around 3 or 4. I'll stick with my 8 - 12% IPA's

  6. Mythbusters by goodmanj · · Score: 4, Interesting

    Mythbusters (accidentally) did it first.

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

  7. 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."
    2. Re:party pooper by BluBrick · · Score: 1

      Lager men than he would overcome that character defect.

      --
      Ahh - My eye!
      The doctor said I'm not supposed to get Slashdot in it!
  8. 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
  9. And no wonder by Anonymous Coward · · Score: 1

    Australians do not like any confusion or doubt when it comes to beer. Mind you, apparently they initially thought it happened because Guiness comes from the North.

  10. 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.
    3. Re:DO NOT by ae1294 · · Score: 1

      Do not touch pint glass with anti-pint glass in remaining space/time...

    4. Re:DO NOT by sharkey · · Score: 1

      Do not cross the stouts?

      --

      --
      "Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
  11. Messy experiment by Anonymous Coward · · Score: 0

    I ran the experiment using an anti-stout glass but my results differed from the theory in original paper - instead of the bubbles rising, they ran all over the floor.

    1. Re:Messy experiment by rickb928 · · Score: 1

      Bubbles got feet!

      --
      deleting the extra space after periods so i can stay relevant, yeah.
  12. 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?
    2. Re:Location, location, location by Anonymous Coward · · Score: 1

      Qantas entanglement.

  13. Math by pcjunky · · Score: 1

    Their answer is "because the math says so"?

    1. Re:Math by idontgno · · Score: 3, Funny
      --
      Welcome to the Panopticon. Used to be a prison, now it's your home.
  14. Re:Wow! Such a thing! Allow me to violate... by Anonymous Coward · · Score: 0

    I got buddies who died face down in the much

    Guess it was
    *sunglasses*
    just too much for them.
    *The Who*

  15. Beer... by Anonymous Coward · · Score: 0

    just wants to be free*.

    * Free as in information - uuuurrrrrp! ('scus me! And CO2).

  16. 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.
  17. Re:Wow! Such a thing! Allow me to violate... by couchslug · · Score: 1

    "I'll have you know the Supreme Court has roundly rejected prior restraint."

    Unless Slashdot is now the US government, that decision doesn't apply.

    --
    "This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
  18. Re:Wow! Such a thing! Allow me to violate... by Jeremiah+Cornelius · · Score: 0

    It'll grow your dingus, massage your warbles and drink your sploodge!

    --
    "Flyin' in just a sweet place,
    Never been known to fail..."
  19. Re:Wow! Such a thing! Allow me to violate... by j00r0m4nc3r · · Score: 0

    It does all three things??

  20. Re:Negative ninety-nine bottles of beer on the wal by CCarrot · · Score: 1

    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.

    Hangin out on the Disc again? Bugarup. Millenium hand and shrimp, I says! :)

    --
    "I love animals! Some are cute, others are tasty, what's not to like?" - Betsy Schroeder, Jeopardy contestant
  21. Beer research?.. Really by Anonymous Coward · · Score: 0

    Come on.. Really? and they got someone to fund this beer research? Damn, those guys are smart!

  22. Yup by Anonymous Coward · · Score: 0

    and a dupe at that

  23. This could put Ireland back into recession by tackledingleberry · · Score: 1

    At the end of the paper they tantalisingly open the door to the possibility that there might exist a glass which would allow Guinness to settle more quickly. If such a glass were discovered, Irish barmen (well, all barmen really) would be able to pull pints more quickly. This means that fewer barmen would be required to man a bar so barmen would lose their jobs, increasing unemployment and probably plunging the country (perhaps the world) further into recession. Risky research.

    1. Re:This could put Ireland back into recession by Palamos · · Score: 1

      All pints of Guinness can be pulled quickly almost independently of the shape of the glass, the current two-stage pouring process was introduced as a marketing ploy some decades ago to make the beer somehow special. I'm not denying that the beer is special, only that it needs to be poured in any special way.