Distillation concentrates the aromas by extracting and filtering out the best volatile compounds from the wine
Alcohol is also found in combination with many other compounds and must therefore be isolated from them.
This operation is performed by distillation.
The principle of distillation is based on the differences in volatility of these compounds (their ability to evaporate depends on their boiling point: the most volatile compound has a lower boiling point than the least volatile).
Thus, the eau-de-vie contains only the volatile substances, which make up the main features of the bouquet.
During distillation, 3 important events occur :
- extraction of volatile substances (the quality of the other substances plays a part, since they represent 0.3 to 1% of the alcohol) ;
- filtering of volatile substances (rectification) : for a wine eau-de-vie, this simply means eliminating the unwanted volatile substances ;
In the end, it can be said that, alcohol (ethanol) is the vehicle that draws out the volatile compounds.