Had to try this on nitro. The beer is expressed totally differently this way, with the wine notes and other sour flavors coming to the forefront. It's still rather opaquely roasty, although it doesn't come across as ashy as with CO2. Didn't sense much bourbon. The nitro does give this a bit of a weird, vegetal overtaste which prevented me from falling in love, but it made me wonder how this version would age.