Getting Legs on Your Wine: Does it Really Happen?

A few weeks ago I attended a dinner party hosted by my wife’s employer who happens to be a successful facial plastic surgeon in the upscale city of Annapolis, Maryland. Immersed in a room that is occupied by many, many people with careers way more distinguished than my own, I’ve decided to lay back and let my wife do her rounds of mingling.  As I’m standing next to a window overlooking the Severn River (beautiful at sunset, I do recommend the view) I found a lot of these people swirling their wine glasses around.  Now, I don’t claim to be a wine enthusiast by any stretch of the word, my wife takes that role, but I have had a few glasses here and there.  I usually just drink it and not think too much about it, though I should put more thought into what goes into the wine.  (From what I understand wine making is a very precise and intricate process). However, I’ve seen this action done by people who know their wine and I’ve always wondered what the purpose was.   Is it a technique to “jumpstart” the wine?  Does it activate something in it? Or is it just a nervous twitch that people in uncomfortable situations tend to subconsciously do.
I asked my wife and she gave me a two part answer.  First she told me that wine, being somewhat organic in nature, needs to breath and the action of swirling allows the wine to open up and release flavor.  Ok, makes sense I suppose, but her second answer sounded a little less scientific.  She told me that legs are a sign of good wine.
Come again?
She proceeded to say that when you swirl the glass around, the wine will leave tear like residue on the on the glass resembling “legs”, thus indicating a high quality wine.  Ok gotcha, wait a minute.. Why would that indicate good wine?  This was the extent to which she could answer; she couldn’t get into the science of it.  So my inquiring mind needed to know what about leggy wine made it superior to its counterpart.  For the record, I tend to listen to whatever my wife says but sometimes it’s fun to call her on her bluff.
After a little bit of research and investigation I came up with some tasty nuggets.  The myth that “legs” or “tears” in wine indicate high quality is just that, myth.  They are in no way an indication of high quality product.  The reality is that “legs” or “tears” in wine are a product of the level of ethanol in the wine, higher levels of ethanol, roughly 12% or higher, will result in this effect.  There are physics and science that go into this explanation, which I will spare you and just give you meat and potatoes.  As you swirl your glass of wine around, the wine goes up the side of the glass.  The two primary components of wine are alcohol (ethanol) and water. Alcohol evaporates faster than water.  As it evaporates, gravity takes over leaving the remaining water to run down the glass in tears. The residue is observable because the differences in how light is refracted by both water and alcohol.  This effect is known as the Gibbs-Marangoni effect, and is named after two scientists whom investigated this phenomenon.
There you have it, this myth has been busted.  However, there is a sliver of truth to this.  Quality of wine is in the eye of the beholder (especially if the beholders make wine at home) and if you value a wine that’s a little more potent, than “legs”, can be one of your best friends.