Oh, I don't mind things slipping off on an interesting tangent, I'm a bit of master of thread-jacking myself
I certainly didn't know that thing about lead as a sweetener in wine, so now I've learned something new.
But back OT, I figure we've ignored something basic. This is a magical world, with sun magic (among other things). In the real world, creating UV rays isn't too hard, just look at those people who grow pot in their basement under sunlamps. So why can't the Dwarves, and in our case, particularly the Luichurp, just magic up a suitable source of sunlight to power the photosynthesis in a vast network of underground fields? I was thinking I'd maybe use that little idea for a flavour text on the Kazad.