Brewpi fridge temp is changing on it's own


Hi all,

Sunday I had a brewday with my father, after brewing we’ve transferred our wort to our fermenters, pitched the yeast and placed them in our isolated fermentation chamber.

The chamber is 3x3m and has an old wall heater and an airco unit connected to our BrewPi running photon version 0.5.2 and latest BrewPi software (release of 23 sep 2017) commit 2282837df5f0bb171ae58302b7780d5d50d213e2.

The BrewPi screen is connected via USB to the Pi (No extra PSU connected).

Since Sunday we seem the following odd issue occuring.
The set chamber temp of 22C suddenly drops (and sets!) itself to 15C, then it changes back to 22C and climbs and holds the temp.

Seems this is happening since the transfer last Sunday…
Since yesterday the fridge setting is set to 20,5C for a better fermentation profile (we’ve divided our batch into two barrels one with 20L with Wyeast 1214 XL and 40L with Safbrew BE-256 to see and taste the difference).

Anybody knows why this is happening?

Attached is the log of our BrewPi




Has this happened more than once? Can you show the beer setting in your chart too?

In beer constant/profile mode, the fridge setting is automatically adjusted.


Hi Elco,

Seems this is the first time we have this issue.

Please see attached

The small dips are from our own actions as we openened the door.
The big dip is not done by us and nothing changed in our settings.

The two small dips on the 16th and 18th are not by us.
The exterior roomtemp never dropped below 5C.

Thank for looking into this!



I just thought about this, could it be that it’s normal behavior in way due to a bad setting/ finetuning?

At the time that the big drop happened the fermentation was really active and rised from little below 20 to 26…


No, the fridge temp will only change based on the beer temp if you are running in a beer control mode. Which leads me to asking: why aren’t you?


That was because at the start of the fermentation the temperature of the beer was too high, so the fermentation stopped. And then we’ve changed the temperature settings from beer to room to give a steady 21C, then the fermentation picked up again.

The chamber is 3x3x3 large, so too much heat was produced (as you can see in the beginning with nearly 30C).