Notice that Pickerell's definition of bourbon doesn't include any aging requirements. Even though there is no minimum, it's a common preconception that bourbon must be barreled for at least two years. Pickerell has dispelled this theory, even amongst fellow distillers, by creating a dummy brand of whiskey he dubbed White Dog. Made just like Maker's Mark, Pickerell barreled his fake label, rolled it down the barreling line and emptied it. Technically White Dog is bourbon, even though the clear spirit spent less than a day inside a barrel.
There are labeling standards for bourbon, however. At two years the label can use the state's name in which it was distilled and be called straight, ie. Kentucky Straight Bourbon. After four years of aging the label does not need to have the state's name imprinted on it.