Why does beer profile mode not work well when the beer sensor is not in beer?

Finished cold crash, ramping up from 32 to 38.

If you don’t have your sensor in a beer (judging from your chart, it seems to have the same temperature as the fridge air, it is better to use fridge constant mode.

In a beer mode, the fridge is adjusting the fridge setpoint to achieve a certain beer temperature. On a sudden drop in temperature for the beer, the fridge setpoint will rise, as you can see in the chart.

If the fridge temperature and beer temperature change at the same time, this algorithm that adjusts the fridge setpoint based on the beer temp does not work well.

If you want the fridge setpoint to just track the beer setpoint, you can achieve this by setting Kp, Ti and Td to zero for the beer-to-fridge PID.

Thanks Elco, I was going to ask this. I kegged and was just raising to 38 for carbonation and storage. I could have just set fridge constant mode at that point.

But when fermenting when switching from a thermowell to just using ambient, say after you start to ramp down to a low temp and put in an S airlock, I was going to ask how to do this. So I will tweak those parameters as you suggest.