Ozwald wrote:That would be more of a cleaning issue, but it's left me rather puzzled. If there was a trace of yeast left in there from a previous batch I would expect that there would be other crap left behind as well. Namely, bacteria as it tends to be much more resilient than yeast. Did you try a forced ferment or leaving a bottle out warm?
I haven't done either yet, but I could give it a shot. If I go the route of leaving a bottle out warm, how long I should leave it out and what should I be looking for afterward? I'm guessing the off flavors would get more intense?