Ask Mr. Wizard

Wort Temperature During Fermentation


Jim Beyette - Ogdensburg, New York asks,

I have set aside a specific room for fermenting my beer. I have set up a heat-cool thermostat with heating and cooling to maintain an ambient temperature of 70° F as I am making only ales. My system is working fine — it controls room temperature perfectly. However, my fermentation temperature is at 74° F. I know this is true because I have a uni-tank-style fermenter with a thermometer in it. Does fermentation activity cause increased temperature, and if so should I compensate for it?

An active fermentation does create an appreciable amount of heat energy. In small fermenters where the ambient air temperature is used for cooling, there is always an increase in fermentation temperature as
Response by Ashton Lewis.