Controlling fermentation temperature

Fermenting an IPA using my new Johnson controls temperature controller. This device is suppose to override the temperature of any refrigerator you hook it up to. At first it seemed to be working fine right after pitching yeast. As the beer got to be very active, the controller didn't seem to be doing its job. We have the sensor for the controller suspended in the fridge right next to the fermentor and set at 65 degrees but as the fermentation temperature rises, the fridge doesn't seem to be kicking on to cool it down inside. The beer is now fermenting at 72 degrees which is 4 degrees higher than I want it. Does anyone out there have experience/ tips or suggestions for using a controlled fermentation fridge? Any advice would be greatly appreciated. Cheers!

 

I have a Johnson analog controller and it has a swing of 4 degrees. I always set mine a bit lower then I want it at and adjust based on a separate thermometer I have taped to the side of the fermenter.

 

You're measuring air temp, not beer temp, you want to reverse that.

Attach the probe to the side of your fermenter and cover with an insulation (can coozies work great)

 

Yeah, you definitely need to be measuring the temp of your fermenting beer, not the temp of the air in the fridge.

Attaching it to your fermenter with some insulation should be good, but some people use thermowells instead, which allow you to measure the temp inside your fermenter a bit.

Also, keep in mind that with just a Johnson and fridge you're only tackling one side of the equation. Depending on where you're fermenting, and what you're fermenting, it could be too cold for proper fermentation. To counter this some people use a dual-stage temperature controller which is capable of controlling both a cooling and heating source.

 

I’m not sure how the Johnson Controls unit works, but if it’s a similar principle to the STC-1000 that I use, then make sure the fridge’s temp control is set high enough. For most fridges I’ve seen, “turning up” the dial on the fridge means more cooling (i.e., lower temperatures inside the fridge).

I just turn mine up almost full blast, that way I can ensure that the on/off of the fridge is being completely dictated by the STC-1000. If you set the fridge control too low, then the built-in temp control of the fridge will shut the fridge off whenever its built-in controller is satisfied, regardless of what your add-on fermentation controller is trying to achieve.

And definitely attach that probe directly to the fermentor, and shield it from the ambient air in the fridge, unless you want to accelerate the failure of the fridge’s compressor.

 

Just as others have said you need to attached it to your carboy and have it contacting beer. Either use a folded up paper towel or a thermowell and you'll now be controlling the temp of beer. It's easier than controlling ambient because some yeast are more exothermic than others.