Falling Stout Bubbles Explainedfrom BBC News Online

Have a question or want to show off your project? Post it! No Registration Necessary.  Now with pictures!

Falling Stout Bubbles Explainedfrom BBC News Online

Irish mathematicians may have solved the mystery of why bubbles in
stout beers such as Guinness sink: it may simply be down to the glass.
Simulations suggest an upward flow at the glass's centre and a
downward flow at its edges in which the liquid carried the bubbles
down with it.

But the reasons behind this flow pattern remained a mystery. Now a
study on the Arxiv server reports simulations and experiments showing
the standard glass' shape is responsible.

Many stout beers contain nitrogen as well as the carbon dioxide that
is present in all beers. Because nitrogen is less likely to dissolve
in liquid, that results in smaller and longer-lasting bubbles. But it
is the sinking bubble that has confounded physicists and
mathematicians alike for decades.



Site Timeline