(Sorry for the long thread, but I want give as much detail as possible) I put my sour mash in the fridge attempting stop the souring for a few days before my brew day. I was souring wort in two 1 gallon jugs. One of gallons no longer has activity, but the other, the best way to describe it is effervescent-like activity in the jug, like bubbles when you open a 2L bottle of soda, right there going on in the 38F fridge. But this just keeps going and going. Few note about my steps. Heated 2 gallons of water enough to mix 2 lbs of light DME. It got a little hot, so I had to cool it down in an ice bath to what I guessed was around 100 F. I poured the wort into two sanitized, 1-gallon cider glass jugs via sanitized pyrex measuring cup and filled it all the way to the neck to eliminate air space Put 2 oz of crushed Pilsner malt in each and topped it off with CO2. My intention was to put a stopper and airlock on each, but the airlock was too tall to fit in the container I was using to insulate the sour mash, so I stuck the drilled stopper on anyway and tightly wrapped foil over the top. I put a heating pad underneath the jugs, plugged it into my thermostat, and set it for 43C, wrapped the jugs in towels, and covered the container. The heating pad didn't get the temp up more than 33C In both jugs, I observed the tiny bubbles in the sour mash as described above, and some of the grain floating to the top. After 72 hours, I took the foil off the first jug, took a whiff and it had a very pleasant, sour smell, but not the putrid vomit smell that I've read about. Not offensive at all. The 2nd jug had a very faint sour smell, but still smelled of sweet wort and honey. Stuck an airlock on 1st jug and put in the fridge -- but kept souring the 2nd. 24 hours later, no more activity in the 1st jug in the fridge and the grain sunk to the bottom Smelled the 2nd jug again, not much of a change, maybe some more sourness, maybe just wishful thinking, but I put airlock on that and in the fridge too. 24 hours later, the 2nd jug still has lots of tiny bubbles as seen through the clear glass, but no big bubbles in air lock. 24 hours later, same. Took the airlock off and took a whiff, little sour, but not like the first, but definitely not offensive. So I'm definitely using the 1st on for my partial sour mash. But what about the 2nd one? What's going on in there? I pretty much had the same process for each one. Perhaps I didn't thoroughly clean and sanitize the 2nd jug and there's some bug in there that survives 38 F temps. Don't know. I think I'm dumping the 2nd.
