🍷 Tears of wine

Tears of wine, or legs, are drops that run down the side of a glass after the wine is swirled. A film is left on the glass, and clear trails slowly crawl down it. Many people think they are a sign of quality, but in fact they are not.

The cause is alcohol. Alcohol evaporates faster than water, especially at the glass wall where the wine is a thin layer. Surface tension of the liquid there becomes higher, and the wine is pulled upward. It then gathers into drops and runs down. This effect is named after the Italian physicist Carlo Marangoni.

Tears are tied to wine in general and to alcohol in wine. The more alcohol, the more visible the tears, so strong wines show more of them. But you cannot judge a wine's quality by them: they only say something about strength and sugar. Good wines can have barely visible tears and ordinary ones thick tears. Germans call the effect church windows, and the French call it tears.