I tried something new today when I pitched a batch and it backfired.
Normally, I finish the boil then cool the whole pot over several minutes or hours in an ice bath to ~78 degrees before pitching.
Today's recipe called for boiling a concentrated batch, then flash cooling to around 150 degrees, then adding this half batch to a half batch of cooled water already in my fermenter.
I did this, but instead of going down to my 75-80 degree target, it just sat at ~88-90 degrees for over an hour. I wrapped it in ice packs, I put it outside (covered) on a cold night, it wouldn't budge.
Finally I threw the whole bucket into a swamp cooler in the bath tub. It is now around target at 81 and I am about to pitch. But it sat at 85-90 for well over an hour.
My question is, how real then is the risk of DMS or contaminants growing because of a cool that slow?
My impression is the risk is pretty low, but I'd like some opinions.