When discussing the legs or tears of a wine, I often joke that “alcohol and sugar contribute to fat legs in women and in wine.” It usually gets a laugh, but more importantly it makes people remember the note. So what do we mean by the “legs” of a wine? Basically, the legs of a wine refers to the tearing effect on the side of a glass of wine due to surface tension. Here’s the Skinny Science you need to know:
If water molecules had it their way, they would travel up the sides of your glass the minute you turn off the tap. But they don’t, and for good reason. The attraction between each water molecule within the water is stronger than the attraction with the glass. So the water stays put. This is called surface tension. In the case of wine, the alcohol reduces this tension and permits the wine to cling to the sides of the glass as we swirl. With more swirling, the alcohol begins to evaporate, the tension increases again, and the tears are pulled back down into the glass – with the help of gravity.
To see the legs, tilt your glass back and forth a few times. Then hold the glass straight up under good light. You should see streaks or tears of wine forming on the sides of the glass. If the wine is has alot of red extracts, such as California Zinfandel, you might even see light red to pinky color in the tears. (Hold a white sheet of paper behind the glass and you will see what I mean.)While legs are NOT an indication of QUALITY. They can tell us something about the wine.
1) Wines with thicker legs tend to be higher in alcohol.
2) Typically, wines with more alcohol are crafted in warmer regions. Stained tears confirm a warmer climate where grape can fully ripen and offer extra color and extract. Good clue for blind tastings.
3) The higher the alcohol, the fuller the body so we can anticipate the body of the wine from the legs.
4) Sugar also increases the viscosity of the wine creating fat legs to move slowly down the glass. Dessert wines always have thicker legs.
Who said science wasn’t fun? Cheers.