Have you ever heard of “the angels’ share”?
It is an expression used to describe the alcohol that evaporates from barrels during maturing. The story goes that a priest coined the expression after finding that his barrel of maturing wine had lost some of its contents even though it was perfectly sealed. He concluded that the angels had taken their share. In order to make up for the loss and prevent the wine from oxidizing, the barrels are topped up every couple of weeks.