Eight years, if I remember correctly.
They are the exact same whiskey except for the type of cask used. The great difference in the TTB designations is a function of the peculiarities of the rules. Because it is aged in used cooperage it can't be called straight and can't even be called 'rye whiskey,' and so the only prescribed designation that allows you to say 'rye' is 'whiskey distilled from rye mash.'



