Thanks a lot for your replies; quite interesting indeed, it had crossed my mind that it may be Perique-related, but I'd assumed it would require far more pressure than merely pressing in the leaves and screwing them tight with the lid. Don't get me wrong, I love the flavour, it's only regrettable that differences in strain don't quite shine through. Doesn't make much of a difference which leaf I use, they tend to have minor differences only. Side by side, you'd never know which strain it is. Could also be my palate's a bit dead, so perhaps my assessment isn't saying much. I guess it makes sense that it's Perique and/or pressure related; last year, there were many crystals forming on there which someone had identified as sugars coming out of the leaf; also, there was some weird stuff forming on some leaves after they'd finished fermenting, which retrospectively felt and looked a lot like yeast. It definitely wasn't mould, never knew what it was, though, but it does make loads more sense now. Does this also explain why really badly cured leaf turns out fine as well? Put some in there that were pretty green, and they got out without any hint of burnt hair or anything. I presume the colour can be attributed to the water. When I set out to grow my own years ago, I'd never have thought growing and especially finishing tobacco would be such a science
My intention is to make cigar tobacco, though since I supply all of my family (parents and girlfriend), it's fairly exclusively used for dark cigarette tobacco (manage to get the odd cigar, or rather cigarillo, rolled here and there, but spatial constraints mean I need to be very conservative with how many I make if I want them the baccy to last till the next growing season). That being said, one of the perks of this approach is that it can go straight from the jar into the fag (after drying, obviously) and it already tastes great. Dunno whether it gets much better with time since regrettably, I've never been able to store them for any significant period of time. To complicate matters, the only place I can cure is in the basement, which worked wonderfully last year due to extraordinarily high temperatures, but this year, coupled with more rain, it just screams mould. Since it's a small room, I have to hang them in bunches of 30 leaves, which doesn't help much with the mould issue, but is still loads better than any barns I've hung them so far, which have led to losses of up to 80-90% of my harvest. Simply storage of dried baccy seems to work fine, however. Oh well, I've put up a fan in there, hope that helps things a bit.
EDIT:
Forgot to add the rope tobacco. Looking at the finished product, it is quite reminiscent of what's coming of of my jars, not quite as dark perhaps, but close. Forgot to further mention that I do all my curing without the midrib due to its tendency to a) catch mould and b) snap easily when forcing it into the jar.