The movement of wine between arches and tears.

How many times have we found ourselves staring at the wall of a glass just poured with wine. We are captivated by the slow flow and try in various ways to interpret those strange drops that fall abundantly forming perfect arches. It is at this point that we start making assumptions, giving explanations; and we always find the coolest person of the evening who explains everything to us… and maybe they really know. But why do the arches form on the wall of the glass? Why are the tears more or less slow? Why are the arches in spirits so narrow and in wines instead wider? What determines these phenomena?

In wine, there are two fundamental components derived from the fermentation processes known as alcohol and glycerol. They are two compounds that are chemically defined as organic because they come directly from nature and are not synthetic. Ethyl alcohol is formed from the transformation of sugars by yeast; glycerol is a by-product of fermentation and is linked to the concentration of glucose. If this is in high quantity, it is released more significantly into the wine. In fact, the concentration of glycerin in sweet wines is high, and the same applies to wines derived from grapes that are dried.

Well, we can get an idea of the composition of the wine from the glass.
In fact, the arches and their width are determined by the alcohol that evaporates and thus lifts the veil of the falling liquid. Glycerin, on the other hand, is the main component of the tears; the more viscous and slower they are, the greater the concentration of this compound. 

Imperceptible arches: alcoholic concentration 11 – 12.5 % Vol.
Tall and wide arches: alcoholic concentration 13 – 16% Vol. (low glycerin concentration).
Tall and narrow arches: alcoholic concentration 13-17% Vol. (high glycerin concentration)

Therefore, remember that:
- if the arches are tall but wide, the wines will be alcoholic without a great body;
- if the arches are tall but narrow, the wines will be alcoholic with a nice structure and consistency on the palate (an Amarone, a Barolo, a Brunello behave like this!).

Fabio De Vecchi