Do you know what wine tears are?
During wine tasting, it's very common to swirl the glass to smell the aromas. When this happens, the wine's famous "tears" are created on the sides of the glass.
When swirling the glass, a liquid film forms on its walls. Then, through capillary action (when liquids travel through small surfaces), the wine rises, forming rivulets that then descend through the bowl.
Because alcohol is more volatile, it evaporates faster. Therefore, this thin, more watery layer, which has a higher surface tension, begins to run off like tears. This explains why the alcohol concentration is noticeable. The higher the alcohol volume, the more abundant the streaks are.
It is through the quantity of these "tears" that run down the glass that the observer can draw conclusions about the alcohol content and body of the drink. To know if the wine is more or less full-bodied, the characteristic to pay attention to is the speed at which they fall. If it is slower and more prolonged, the conclusion is that we have a drink with more body.
