Coffee flavors don't usually crack tanks. I think it is mostly cinnamon and some acidic fruit flavors, probably a couple others. Replacing the plastic in the tank could work but would probably be more trouble than it is worth. I lost a T3 not long ago due to a crack in the tank where it is glued to the metal piece at the bottom. I tried gluing it but never did get it to stop leaking and just tossed it. I really got to work at not dropping everything all the time.