The vanilla compounds from the spirit barrel combine with the fruity esters from the Belgian yeast, and in the case of this particular beer, some tropical fruit and citrus notes from the hops that we chose for the whirlpool addition.  The furan compounds in the bourbon barrel will give some light caramel and toffee notes to the beer, and a slight perceived sweetness.  All this combines to give a flavor profile that is a little reminiscent of a white wine.  There is also some significant bourbon flavor, but the synergistic effect that that you would find with a more malt forward beer like IRS (Stone Imperial Russian Stout) aged in bourbon barrels and Double Bastard Ale aged in bourbon barrels is not a big part of the flavor profile in this beer, but still plays a role. The white wine flavor is something we have been pleasantly surprised by with a few Belgian Yeast and Bourbon Barrel experiments.