I think bourbon-whiskey is made with different ingredients (mixed corns, rye, and malted barley) and then fermented. Once the fermentation is done they have what is called "distiller's beer" and then they run it into the distiller.
The first run is called "low-wine" and is run again and yields "high-wine" or "white-dog" or "green-whiskey"
The yield from that run is water clear. The color and much of the flavor comes from the aging time in charred oak barrels. The longer it sits in the barrels, the more flavor is leeched from the wood, yadda yadda. Under the law, to be labeled and sold as "straight bourbon" it has be aged in new, charred oak barrels for at least two years.
That's about what I know of bourbon-whiskey. The process and definitions are different for Tennessee whiskey, Canadian Whiskey, Rye Whiskey, Blended Whiskey, etc.
cheers,
Oskaar