We now know what causes wine ‘legs’ to drip down inside a glass

By Layal Liverpool

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The drops that run down the inside of a glass after wine is swirled – called “legs” or “tears” – are caused by a shock wave interrupting the ring of fluid that sticks to the glass.

We know that a film of wine can flow up the side of a glass after swirling because the alcohol in wine evaporates faster than the water, creating a difference in surface tension that drives liquid upward. But exactly what caused wine tears to form was a mystery until now.

Hangjie Ji at the …