Have you ever swirled a glass of red wine and seen clear streaks on the side of your glass? Or maybe heard someone comment on the “legs” or “tears” of a wine? We know it can’t walk or cry, so what does this mean?
Here’s a bit of wine trivia for you to impress your friends and family – it is a phenomenon called the Gibbs-Marangoni Effect.
This visual experience of “legs” or tears” running down the side of your glass relates directly to the viscosity, the state of being thick, sticky, and semifluid in consistency, due to internal friction.
Higher viscosity is found in wines that are higher in alcohol, higher in sugar, or both.
The Gibbs-Marangoni Effect is caused by fluid surface tension created from evaporating alcohol in the glass. As you swirl or take a sip, some of the alcohol becomes volatile and is released into the air in the glass. Ethanol, the alcohol in wine, has a tendency to evaporate from the wine where the surface fluid comes into contact with the inside surface of a wine glass
While temperature and humidity can affect the phenomenon, generally the “legs” or “tears” indicate a higher level of alcohol. It is most evident in red wine because of the color and because red wines tend to be higher in alcohol. Remember, you may also see this in a sweet wine and a wine with high alcohol and high residual sugar like a port.
Here’s quick video to help you understand this concept. Wine + science!
