Any beverage left to age in wooden barrels will ultimately lose some of its volume to evaporation through the porous wooden staves. Whether wine or whiskey, its producers affectionately and poetically refer to this sacrifice as the “angels’ share”. However, there is one region in particular for which the turn of phrase is known—Cognac. The wines of Cognac are distilled into a clear, harsh spirit called eau-de-vie, or “water of life.” What transforms the spirit into Cognac is long aging in oak. Left in barrels for years (often many decades), the water in the Cognac gradually evaporates, as does up to 5 percent of pure alcohol, which the vignerons call “la part des anges.” Given the vast number of barrels in the Cognac region, it’s estimated that about 32 million bottles’ worth of the brandy evaporates yearly.