The production of whiskey is considered very interesting and fully understood, and factors like whiskey barrels that create the interaction between the oak and the whiskey play very important roles. For your information, the new spirit of whiskey gains character and color from the oak wood, that the whiskey barrel is made of, of which the spirit is stored into, thus the quality of the whiskey barrels is carefully monitored.
There are some barrels that were used for spirits like oloroso for its maturation, fino or amontillado sherries, bourbon and oak. Read more about Red Head Oak Barrels
So that there is a continuity of the whiskey and attainment of a certain character of the spirit, the master blender has to make a careful selection of type of whiskey to be used for maturation.
Be informed that a new make spirit can only be defined legally as scotch whiskey only after at least maturation of three years. Note however that many scotch whiskey are made to mature for longer period of time, like five, fifteen, twenty and twenty five years and some even longer. https://en.wikipedia.org/wiki/Distilled_beverage
It is claimed that the cool, clean air of Scotland that penetrates into the porous oak material of the barrel, and how the interaction between the wood and the spirit that contributes to the smooth and golden character of the creation of the distillery.
Know that part of the content of whiskey in a cask would evaporate each year and is said to be lost to the heavens leading to the term “angel’s share”.
Among the most questions asked in the industry is that why is whiskey barrels made of oak is used by whiskey makers. The unique physical and chemical nature of oak, its physical strength brought about by its wide radial rays that give strength once formed into a cask, and its purity as a wood with the resin canals that allow strong flavors to reach a mature whiskey, are among the reasons why oak wood is a preference for whiskey barrels. More info at this site
Not only that, there is a transformation happening to the oak as a result of the heating and seasoning treatments during the process of coopering that leads to the result of a pleasant tasting lactones of oak.
Know that there are three effects on the spirit that happen when whiskey barrels are produced from oak wood.
The number one effect of an oak whiskey barrel is it acts as an additive, meaning the aroma and taste of the spirit are enhanced from the desirable elements present in the wood. Vanillin, oak lactone, toastiness, wood sugars and color are among the additives components of oak.
The second element of oak wood is that it acts as a medium that would remove elements that are not needed to make a new whiskey, such as sulphur compounds and immaturity.