I recently did a sour mash for a berliner weisse. I used the full mash volume with 7# of grain and 3 gallons water held at 115 degrees for 48 hours. I covered the mash with a layer of foil and plastic wrap over the top. There was a definite sourness and a lot of 'vomit' smell. Unfortunately I did not test the pH. When I opened it up there were small holes in the foil. Could this have been from acid dissolving the aluminum? or just being held at 115 degrees? Is this safe?
Second, when I pitched my yeast, S05, it was 24-36 hours before I noticed any activity in the airlock, and then it seemed to stay slow. Now, after 7 days it is still bubbling, but very slow. Was the yeast slowed by the acid? Do I need to give it more time to avoid diacetyl? Alcohol was only supposed to by 3.3 abv, should this complete fermentation?