Secret to keeping drinks cool could have global implications

UW scientists have provided fresh insight into an issue that has vexed civilization since the beginning: how to keep a drink cold on a hot day. It turns out that condensation on the outside of a canned beverage can provide more heat than the surrounding air, meaning your drink would warm more than twice as much in humid weather as in dry heat.

“Probably the most important thing a beer koozie does is not simply insulate the can, but keep condensation from forming on the outside of it,” explains Dale Durran, UW professor of atmospheric sciences. Durran is co-author of results published in Physics Today that give the exact warming for a range of plausible summer temperatures and humidity levels. For example, on the hottest, most humid day in Dhahran, Saudi Arabia, condensation alone would warm a can from near-freezing temperature to 48 degrees Fahrenheit in just five minutes.

The phenomenon at work—latent heat of condensation—has implications beyond keeping you refreshed on a summer day. The concept is central to research on water vapor, heat transfer and global climate change being conducted by co-author Dargan Frierson, UW associate professor of atmospheric sciences. “We expect a much moister atmosphere with global warming because warmer air can hold a lot more water vapor,” Frierson reports.