One explanation for why the bourbon and whiskey from Kentucky (and really, is there any other kind?) is so good? The water:
Kentucky’s water is special. It flows through limestone, which makes it high in magnesium and calciumâ€”minerals that also contribute to the magnificence of the state’s racehorsesâ€” and low in iron. These characteristics are good for fermentation and for the eventual flavor of the whiskey.
Also, by legislation, whiskey must be aged in a barrel for 2 years before it can be referred to as bourbon.