ow is Buffalo Trace made, anyway? Rye, barley and corn go into every bottle of it, and this bourbon follows a tried-and-true fermentation and distillation process. Buffalo Trace Bourbon is aged in new, charred oak barrels for at least eight years to give every bottle its distinctive taste. The centuries-old aging warehouses only add to the flavor. Every bottle of Buffalo Trace is 90-proof. That makes it ideal for sipping slowly or mixing into your favorite cocktail.