Is there a fermentation controller that does this?

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Oct 10, 2008
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In my great move-the-brewing-area-to-the-garage movement, I am looking at either doing two mini-fridge-collared fermentation chambers, or doing one larger mini-fridge-powered one. In the case of the second, is there a fermentation controller that would have one cooling circuit and two heating circuits? I'd like the possibility of having two different fermentation temperatures available, but I would only have one power control for the fridge. Essentially, I'd like an "OR" on the cooling circuits for the two thermostats.
I'm not aware of an off-the-shelf single solution for this configuration, but your notion of OR-ing the cooling outputs from a pair of dual-stage controllers with separate heat blankets or heat matts has been used before particularly in use with chest freezer based chambers.

This could also be done with two instances of BrewPi or Fermentrack running on a shared host, which would bring the fairly significant benefit of per-instance temperature charting (not to mention programmed ramping) so one could see what was going on...

If it were me, I’d throw a couple of 120 V relays in a box and do it that way. Each temperature controller’s cold outlet would power a coil, and the NO outputs of the relays would be tied together. Stupid simple, should work.
Even easier would be to get two of the Inkbirds that have relay outputs instead of 120 V outlets. I don’t see any reason you couldn’t just tie the two cold outputs together to get your OR. You’ll have to connect wires and a receptacle, but it’s as close to off the shelf as you can get.

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