Post Ferm Temp Rise !

[Todd]

After ten years of brewing I came across a first yesterday!

After four days away from this new start-up brewery, I came home to nearly pasteurized beer in the CCFV! I had already completed a VDK rest, warm side yeast harvest, crash cool, cold side yeast harvest, and nearly 12 days of cold conditioning with successive yeast dumps. The beer was bunged and had 10psi head pressure. When I left the brewery four days earlier the beer was resting at 32F. When I returned the beer was at 93F!

Simply put, the compressor/condenser went into FreezeStat and quit operating because our local ambient (outdoor) temperatures reached 10 F. The HVAC contractor admitted not having something correctly set for low temps (unfortunately he wouldn't elaborate). The glycol reservoir pump continued to run through the compressor/condenser, as did the header pump to the fermentation loop. The beer warmed rapidly due to this failure. Live and learn!

Has anyone experienced this significant of a temperature rise in post fermentation, pre packaging (outside of pasteurization) ? Outside of the normal scientific consequences, what was your resulting finished product like?

Any information is “warmly” welcome!!

[kugeman]

Todd,
I have had this happen several times. The usual culprit is the incorrect ratio of glycol/water. Basically if there isn't enough glycol in your mix the cooling liquid can actually freeze when the ambient temperature gets cold enough. Our brewery is in the Adirondack Mts of northern New York State, so needless to say, when the mercury hit 30 below a few years ago things went a little haywire.

I have had beers that went through primary ferment way too hot (Belgian Tripel at 95F actually came out pretty well. English Red Ale at 85F tasted horrible and had to be dumped). I have had other beers that just got unnaturally heated during cold conditioning as seems to be the case with you. It will depend a little bit on the beer as to how it turns out. In my case they were fine. I noticed no off flavors or change in the beer's character. You may run inot problems with shelf life, but in my case the beer sold fast enought that I didn't notice. But I did notice problems with yeast performance (viability and flocculation) with subsequent pitchings of that yeast.

I would say, chill the beer back down and let your tastebuds be the judge. I think you'll probably be ok.

Cheers!