“Ah, those wine legs indicate that this wine has a high amount of glycerine! It is, therefore, a grand wine!”

Spoken like a true wine bougie. But – is that even true?
Not quite. Like all wine myths, there is some truth to it. The legs of the wine, which unsurprisingly have a much more romantic name in French (“larmes de vin” – wine tears), and a somewhat austere one in German (“church windows” – because they resemble those arched windows typically found in Gothic churches), form because of the Marangoni effect: alcohol evaporates more quickly than water. The alcohol (ethanol) in wine crawls up the glass as it evaporates, but because there is a film of water on top, it is pushed up in a “church window” arch. Eventually gravity wins, the water’s surface tension is broken, and down runs the water, in “wine tears”. Now that we got the physics down pat, let’s just clarify this once and for all:
 Wine legs have nothing to do with the quality of a wine.

What wine legs really mean

First of all, wine legs indicate that there is indeed alcohol in the glass. The shape and consistency of the streaks tell us a lot about the ethanol content of a liquid, but do not allow any further statements about the quality of a liquid. More alcohol leads to thicker “tears” and pointed “church windows”, while a lower alcohol content leads to weaker tears and more rounded window arches. The Marangoni effect is also influenced by the shape of the glass: glasses tapered upwards (like German Schnaps glasses) increase the formation and adhesion of the legs.

But what about the glycerine?

As to glycerine. There is none in wine, simple as that. There is glycerol (which is an alcohol), but that has nothing to do with the Marangoni effect. So let your inner wine bougie shine and correct the non-savant confused bougies trapped believing this wine myth. But most of all: enjoy your glass of wine, Marangoni effect and all.