If the sleeves of your business shirts are all covered in coffee stains, it may be time to start drinking more lattes. A new study reveals why lattes, cappuccinos and other foam-laden coffee drinks are less prone to spillage than a plain cup of joe.
In studying the physical dynamics of sloshing liquids, researchers found that five layers of foam bubbles limited the height of waves ten-fold as compared to plain liquid (like black coffee).
"What we observe in our cups of coffee, this happens every time you're carrying liquids in a container that's partially filled," study co-author Emilie Dressaire, an assistant professor of mechanical and aerospace engineering at New York University, told Popular Science.
Researchers also found the foamy head of a beer has advantages similar to those of the milk bubbles that sit atop espresso
"While I was studying for my Ph.D. in the south of France, we were in a pub, and we noticed that when we were carrying a pint of Guinness, which is a very foamy beer, the sloshing almost didn't happen at all," Alban Sauret, a researcher at the French National Center for Scientific Research (CNRS), said in a press release.
But more than just keeping the skin of caffeine fiends burn-free or keeping beer off the bar counter, the research may also have industrial applications -- like subduing the sloshing of oil and other potentially dangerous substances during transportation on trucks, ocean tankers or trains.
"The potential applications are much bigger than just beer," Sauret said.
The new study was published this week in the journal Physics of Fluids.