Guinness bubbles

[denni89627]

How is it that the bubbles in my favorite beverage sink, unlike any other beer. After a couple minutes of research I found that the bubbles rise in the center of the pint glass but they fall along the edges which is what you see. I understand this principle with heat convection, but not with bubbles!!!! What's going on here?

All wrong answers owe me a fresh pint. (for experimental purposes):rofl:

[Mk]

Why do raisons do the same thing when champagne is poured into a glass with raisons in it?

[denni89627]

Yeah but raisins are heavier than the champagne......
The bubbles seem to go down way after the pour, when i can't imagine there is still that much turbulence in the beer.

[GOD__AM]

If bubbles rise to the top it creates a current moving up in the beer. For there to be a current going up there must be an equal current flowing down.

[josh_einsle]

here is a page by the group in Stanford who along with researchers in Edinburgh who did the experimental work which
a) demonstrates that the bubbles really do go down due to a drag force as mentioned by GOD_AM.
b) links to an article to the researcher who devised the mathmatical model explain the mechanism involved.

what i think is great is that this is not a property of guiness inherently, it is a property of any draught fow beers.... which i always take an oportunity to order just because most tend to be tasty and are so much fun to watch....

so here is the link with out further ado:
http://www.stanford.edu/group/Zarelab/guinness/index.html