I just brewed a no boil Berliner Weisse ten days ago. I let the wort spontaneously ferment for two days beore adding #1007 German Ale. The OG was 1.031, close to target. Yesterday a new fermentation become very active. The large krausen is made of large thin bubbles. The krausen is blowing out the airlock. The krausen is stringy and muscul like and has a very pungent sour aroma that is not pleasent. This is were it gets weird. I removed the airlock and cleaned it. I also cleaned the carboy with water. The aroma from the carboy was much better the the funky mucus coming out. It was fruit and sour. Before replacing the air lock, I flamed the top of the carboy. THE KRAUSEN BURNS! The flame continued down into the carboy and lasted a few seconds before it was snuffed out by lack of oxygen. So what ever is fermenting in there must be producing methane or other flammable gas. I've been brewing since 1992, but this is my first no boil beer. I never seen anything like this. I skimmed Wild Brews, but there were no clues in there. Any ideas what might be working in there and what the byproduct of the fermentation are?