Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.
Dear Dr. Vinny,
What does it mean to say a wine has “legs”?
—Taylor, Winston-Salem, N.C.
A wine’s “legs,” also known as “tears,” are the slowly trickling drops of wine clinging to the side of a wineglass after it’s been swirled.
There’s actually some very cool physics at play when you see those cascading droplets of wine—and it’s similar to what’s happening when you see rain on a car windshield. For many years, legs were attributed to the Marangoni effect: As alcohol evaporates, the surface of the liquid is pushed up the sides of the wineglass, and then collects in “tears” that gravity pulls back down. But thanks to a team of UCLA mathematicians, we now know that the Marangoni effect is only part of the equation. The shape of the legs is caused by “reverse undercompressive shocks,” shock waves in which liquids move against the direction of the wave. (Read more about the science and check out a couple videos in our Unfiltered column.)
Outside of the physics lesson, there’s no existing scientific evidence that legs offer any indication of wine quality. The shape, speed and volume of the legs are influenced by many factors, including the sugar and alcohol content and the temperature of the wine, as well as the temperature and humidity of the room.
I hang out with my share of wine geeks, and I can’t remember the last time someone brought up the subject of “legs.” There was a time when some people believed that observing the legs could bestow some secret knowledge of a wine’s quality, but there’s no evidence to back that up, and assessing them has gone out of fashion.