Bourbon is distilled from a fermented mash of grain, of which at least 51% must be corn. It is bottled between 80 and 125 proof and must be aged at least 2 years in new, charred white-oak barrels (charred to add color and possibly some flavor). Only limestone-filtered spring water may be used to lower alcohol proof. Sour mash is used in most bourbon. It is the residue from a previous mash run, allowed to sour overnight and then added to a new batch of mash, similar to the process for making starter for sourdough bread.
Corn spirits were made as early as 1746, and a distillery was established in Bourbon County in 1783. Elijah Craig is often credited with development of the distinctive taste of bourbon. Craig, a Baptist minister from Royal Springs, Virginia (now named Georgetown, Kentucky) began making his spirits in 1789. It was Dr James C. Crow, a physician and chemist, who introduced the scientific methodology and quality control to Kentucky whiskey making in the 1820s. He also in