Has any one tried this? I'm going to do a berlinerwiess, and I am going to kettle sour my wort by leaving it in my car for a day or two to take advantage of the hot weather we're having. This this will work?
What is your lacto source? In my experience you do not need to maintain that temperature the entire time. I used omegas lacto blend, Swanson's​ probiotic pills and good belly shots with success using the following. I chill to 100f then transfer to a corny keg or a carboy, ourfe with CO2 and seal it up. I don't do anything to maintain that temperature. Last time I did it in a carboy it was still in the 80s 24 hrs later with a room temp in the 60s. After 48 hrs the PH was down to 3.3. I didn't boil that batch to kill of the lacto and it was below 3 when I bottled​.
I had it in my car for a day, and then moved it inside. I think I'll just put it outside when its hot out, and bring it in at night for the next day or two. Then pitch the yeast. I used yogurt and threw in some probiotic pills for good measure. I've used yogurt in a small 1 gallon fermenter before and it worked great, so I thought I'd try it again.