Both are amazing brews. Nocturnum is the pink elephant, Tremens is the pimp alligator.
Tremens is light typical looking Belgian Whit.
Nocturnum is much darker.
I am on the proverbial fence, I am drinking a pint of Nocturnum right now - chilled to perfection, and am loving it. Even though I typically only care for the typical belgian whits.
Opinions?