#39;s for the bourbon die-hards among us. The Whiskey Bros are back in February for a class on barrel proof, or cask-strength bourbon. (This means the whiskey is bottled straight from the barrel. The resulting dram is extremely flavorful, with a much higher proof - typically in the 120-130proof range.) Most whiskeys are watered down out of the barrel to reach the more typical 80-100proof range. Not these puppies! Some would argue that barrel proof bourbon is the purest drinking experience you can have.