The beer is not sour. I have made 5 gallons this way so far. I brew a gallon at a time and bottle with 3/16 of a cup of honey for in bottle fermentation. I really dont think that you are right about the culture just being bacteria two hearted. One sheet layer of cheese cloth is really quite thin...
I have been making my own sour dough bread from base malt wheat that I get from my local brew store. I make my starter with only malt that I mill with my Vitamix blender "dry container" and water. I wild ferment the starter by mixing table spoon for table spoon malt flour and water and let sit...