So last night I created a mash for a Berliner Weisse. My plan was to sour it with the sour wort method. After mashing, I cooled the mash down to 120 degrees, pitched about 10 oz of unmilled Pilsner inside of a sterilized muslin bag into the kettle, then sealed it up with the cover and some saran wrap. I then wrapped it up with some FermWrap, reflective insulation, and a blanket. I was keeping this in my 40 degree garage, so my hope was that it would hold temperature fairly well without losing much. Well, after getting home from work today, I took a temperature reading and....170 degrees! Crap. My question is...what now? I unplugged the FermWrap. Once it cools back down to 120 degrees, can I just throw in some new grain, or should I dump this? There is some sediment of some kind floating on the top, which I assume is just proteins from the grains.
I would re-introduce some new grain to the mash once it has cooled. At 170°, you are not really growing anything in there, good or bad, so no harm done with that small mistake.
Thanks...that's kind of what I was figuring too. I had something going on tonight, so I left the wort to sit for a few hours. When I got home, it was right at 120 degrees again, so I re-added some grains, repurged with CO2 (using carbonated water), and sealed it back up.
Just to double-check, you didn't pitching a commercial lacto culture in there, did you? If so, they're dead. It sounds like you're just hoping to pick up some bugs from a handful of grain, right? If that's true, I agree with bgjohnson ^^^ and I've had great luck with this method twice. A quick boil when you want to lock in your sourness, add a touch of hops, chill, pitch some Kolsch yeast, and you're golden.
Yes, that's correct. I'm just using whatever lacto is living on the handful of grains I'm throwing in. After it cooled to 120 last night, I put more grains in, left the blanket off this time, only loosely wrapped my reflective insulation, and plugged the FermWrap back in. This morning the temperature was....145. Crap again. I guess I'm really underestimating both the amount of heat that the FermWrap is contributing and the ability of the reflective insulation to hold temperature. I considered doing a test of my ability to maintain temperature using only water a few days before beginning this batch....I'm sort of regretting not doing that now. So my wort is cooling down again now, then I will....for the third time....add some more grains. I'll leave the FermWrap unplugged this time and only wrap up the kettle in insulation. On the plus side, the wort does smell slightly of apples, so I think some amount of healthy souring has taken place before the lacto was killed off once again.
90F is better than 145. I bet you'll still be around 100 by the time you get back to it. Add a little hot water if you need to continue souring for another day.
It was 95 when I arrived home. I turned the FermWrap back on and once it hit 115 I loosened up the reflective insulation. By this morning, it was still at 115. I think I found my holding-steady configuration. I'll leave it as is and boil it up and rack it when I get home from work today. It still smells like sour apples, so I think I still have a good, clean sour.
If you think you might do more heated sour wort-ing in the future, I'd recommend you seriously consider some type of thermostatic temp control.
I've already been searching around for some. If anyone knows of any reasonably-priced ones, I'd love to hear recommendations. In the coming summer months when my garage holds a pretty steady 80-90 degrees around the clock, I don't anticipate this being as much of an issue.
You can also sour wort at room temp, just takes a little longer....like conveniently from one weekend to the next.
I've read of people who do that with success, but I'm just a bit leery of unwanted contamination. My goal was to keep it in the 90-120 degree range for the duration of the souring process.
