Legs

What does it mean to say wine has “legs”? The phenomenon known as “legs” (also known as “tears”) manifests itself as a ring of clear liquid that appears near the top of a glass of wine after it is swirled. Droplets form from this ring of liquid and flow in rivulets back into the wine.

Try it for yourself. Fill a wine glass one quarter full and, holding it by the stem, gently move the glass in a circular motion so that the wine swirls up the sides. Now hold the glass up to the light and look for several streams of clear liquid running down the inside of the glass. The liquid may flow down in a fairly even sheet, or it may pull into more concentrated rivulets. These rivulets are what is referred to as the legs of the wine.

It is widely held that the presence and thickness of the legs relates to either the sweetness, viscosity or quality of the wine. None of these is correct. Legs form because of the alcohol content of the wine. The higher the alcohol content, the better legs a wine will have. The legs are produced by the effects of surface tension, adhesion and evaporation. The alcohol, because it has lower surface tension, crawls up the inside of the glass. As the alcohol evaporates, the water concentrates and surface tension pulls the remaining liquid together into droplets. These droplets running down the inside of the glass are the legs. This was first explained by James Thomson in an 1855 paper, “On certain curious Motions observable at the Surfaces of Wine and other Alcoholic Liquors”.


Because a wine’s body is affected by the alcohol content, there is some relationship between legs and body, but there are so many other factors involved that legs are not a reliable indicator of quality. That being the case, you might ask why wine connoisseurs still swirl their wine? Because swirling helps to release aroma molecules from the wine which in turn helps them to better smell and therefore to taste the wine. They also just like looking at the legs, even if they know they don’t mean anything!


Images from the Journal of Nature Science and Technology