No description required!! Ok, yeah there is!
Oak wood contains a large number of chemical compounds and almost every one of them can add a little something to the flavor profile and personality of wine, ale or spirit when kept in contact with it. The most recognizable of these are a wide range of vanilla, tea-like (tannins), caramelized sugars, toast, and tobacco flavors and complimenting aromas. Aging on wood also adds pigmented color elements and hydrolysable compounds, which contribute to mouth feel. Oak aging is an extremely complex subject involving a huge number of factors. Oak can impart varying degrees of flavor traits and qualities depending upon the barrel size and the way it was made. The type of oak used, sawn or hand-split, air-drying or kiln drying of the staves, and the use of boiling water, steam, natural gas, or wood fire to bend the staves. Skilled winemakers may use a combination of both new oak, for more intensity and old oak for elegance. Scotch whisky is aged in used sherry (sometimes in Port barrels) barrels. American Kentucky and Tennessee whiskeys owe their characteristic color and a great deal of their flavor to the use of heavily charred barrels. The charring creates a red layer of caramelized sugars between the charred and un-charred part of the barrel.
All barrels have one thing in common they are relatively porous. This plays a part in another aging factor, oxidation. This very gradual oxidation results in decreased astringency, increased color, stability and the formation of complex fragrances. As the wine, ale or whiskey ages, the barrels breathe. In the case of whiskey, somewhere between eight to ten percent of the alcohol volume will be lost to evaporation in the first year. Evaporation continues over subsequent years at a rate of four to five percent per barrel. A good whiskey is likely to lose approximately thirty percent of its original volume by the time it is ready for bottling.
The expression The Angel’s Share refers to the quantity of the whiskey or wine, which is lost to evaporation during the aging process. In grade school we were told that it was the angel’s job to look after all of us. In today’s perilous world, that must be hauntingly demanding work, which would certainly merit a few perks.