Phenomenica reports on a scientific breakthrough that will truly change the way we think. For centuries the philosopher prince has stared at his pint of stout and wondered why on earth do some bubbles go down towards the bottom of the glass instead of upwards to the light.
This conndrum has now been solved in a new study, mathematicians and it sems to be due to the glass.
Many stout beers contain nitrogen as well as the carbon dioxide that is present in all beers. Since 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 the world's greatest minds
Now the University of Limerick’s William Lee, Eugene Benilov and Cathal Cummins have discovered the simple answer to the problem – and a test that can be carried out by consumers as well.
The team had the idea that the relative density of bubbles and the surrounding liquid could be behind the phenomenon. “If you imagine your pint is full of bubbles, then the bubbles will start to rise... “Because of the sloping wall of the pint, the bubbles are moving away from the wall, which means you’re getting a much denser region next to the wall. That is going to sink under its own gravity, because it’s less buoyant, and that sinking fluid will pull the bubbles down...You’ll see sinking bubbles not because the bubbles themselves are sinking, but because the fluid is and it’s pulling them down with it,”
The same flow pattern occurs with other beers such as lagers, but the larger bubbles of carbon dioxide are less subject to that drag.
Cummins carried out calculations using a simulated pint and “anti-pint” – that is, the upside-down version of a pint glass – showing the effect at work; in the anti-pint, the bubbles rise as expected.
Well there you have it once more. Truly a wonderful discovery. I am a bit oworried by the concept of the Anti-pint. I wonder if it will cost £6.66
This conndrum has now been solved in a new study, mathematicians and it sems to be due to the glass.
Many stout beers contain nitrogen as well as the carbon dioxide that is present in all beers. Since 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 the world's greatest minds
Now the University of Limerick’s William Lee, Eugene Benilov and Cathal Cummins have discovered the simple answer to the problem – and a test that can be carried out by consumers as well.
The team had the idea that the relative density of bubbles and the surrounding liquid could be behind the phenomenon. “If you imagine your pint is full of bubbles, then the bubbles will start to rise... “Because of the sloping wall of the pint, the bubbles are moving away from the wall, which means you’re getting a much denser region next to the wall. That is going to sink under its own gravity, because it’s less buoyant, and that sinking fluid will pull the bubbles down...You’ll see sinking bubbles not because the bubbles themselves are sinking, but because the fluid is and it’s pulling them down with it,”
The same flow pattern occurs with other beers such as lagers, but the larger bubbles of carbon dioxide are less subject to that drag.
Cummins carried out calculations using a simulated pint and “anti-pint” – that is, the upside-down version of a pint glass – showing the effect at work; in the anti-pint, the bubbles rise as expected.
Well there you have it once more. Truly a wonderful discovery. I am a bit oworried by the concept of the Anti-pint. I wonder if it will cost £6.66
