I love Bourbon, in case you are new and have not figured that out yet I figured I better lay that out here right now.  One of the things I love is seeing what effect aging has had on a decent bourbon.  Is it best after four years or six?  Does the recipe have enough sugar to hold up to the barrel and come out better after ten or twenty years than it was when it was meant to be bottled at four?  What different flavors and smells are added or removed with time in supposedly "identical" barrels?