Beer is built not to spill, as bubbles stop drink from sloshing out of glass

Science discovers why you end up with coffee down your shirt far more than beer

A bartender serves beers (Adam Berry/Getty Images)

The foam on the top of beer keeps it from sloshing out of its glass — and that could be why coffee gets spilt so much more often, and why getting lattes might fix that problem.

Scientists, who noticed that beer seemed to be good at staying in its glass if it wasn’t full, mixed water with chemicals that give it a froth. The mix — made of glycerol and surfactants — allowed researchers to change the size of the bubbles and the thickness of the foam, reports the New Scientist.

They found that it was the foam that was keeping the drinks from sloshing out of their glass, by filming the mixture as it was jolted around, and then analysing the videos. Researchers posted videos of the different liquids sloshing around (demonstrated using Guinness, Heineken and freshly-brewed coffee).

They found that 0.3 centimetres of foam stopped much of the sloshing, and 3 centimetres of foam stopped it entirely.

“We conclude that it is much easier to carry beer than coffee,” the researchers said in their submission to the ‘Gallery of Fluid Motion’, a website run by the American Physical Society containing examples of similar experiments as well as artistic takes on fluid motion.

The discovery could be used to keep hazardous fluids from getting spilled, the New Scientist said.