Bourbon vs Whiskey? Bourbon isn’t not whiskey. Yes, its a type of whiskey. One of many. For instance, all bourbon must be distilled in the U.S. Not Kentucky specifically, but the rule has a lot to do with it and the South in general. Legally, it must be distilled from at least 51% corn. The rest can be any combination of rye, barley, and wheat but corn is a requirement. Bourbon must also be aged in new, charred barrels from American white oak.