awesome post! I have nothing for you but awesome post.
I have yet to make a sour, although it is coming up very soon. I actually cultured something from the skin of a plum and have been feeding it small wort starters for a couple months now. I see yeast like activity for sure with some other interesting smells along with it. nothing bad so far and no mold (yea!)
but it's worth trying. what I did was make up three jars with some 1.030 wort and I put a grape from my backyard in one, left one outside overnight and put the plum skin in the third. the outside one grew mold almost immediately
. The grape one was promising at first but then turned to nail polish remover
The third one smelled kind of nice so I put it in the fridge and took it out again the next time I had a little wort left over to feed it. I was going to do a third sparge on my last batch and pitch it into that but I got lazy cause it was late. Next time!