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."

Comments

Now that I know the theory

[cristiroma]

Allow me to practice ...

late to the party

[Anonymous Coward]

The Australians figured it out 12 years ago

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

Re:late to the party

[NatasRevol]

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

Re:late to the party

[Geek70]

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....

American fluid dynamicists did it first!

[Colonel Korn]

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.

Mythbusters

[goodmanj]

Mythbusters (accidentally) did it first.

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

party pooper

[G3ckoG33k]

That's an astout observation!

Hence, no stout for you, mister. ;)

Re:party pooper

[Hognoxious]

You sound bitter.

DO NOT

[Fned]

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

That is all.

Re:DO NOT

[idontgno]

Only after a rather stout explosion, though.

Negative ninety-nine bottles of beer on the wall.

[neoshroom]

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.

Re:Is it replicatable?

[krotkruton]

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.

Re:Is it replicatable?

[BattleApple]

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

Re:Math

[idontgno]

Science. It works, bitches.