Booze boffins solve stout's dark mystery

THE bubbles in a pint of Guinness really do go down instead of up, according to Edinburgh University scientists.

With just about any other pint of beer, the bubbles can be seen to obey the normal laws of physics and rise to the surface to form a frothy head.

But in Guinness the bubbles appear to be cascading down the side of the glass.

Scientists found that the visible outer bubbles are dragged down by circulation flow and drag.

Dr Andrew Alexander, senior lecturer in chemical physics at Edinburgh University, who led the research, said they captured the bubbles going down using a camera which uses 4,500 frames a second and a zoom lens.

He said: "The circulation cells in the glass provide the same effect like you see in a tornado."