Adjusting STC-1000 temp calibration value

[ImperialStout]

STC-1000 set to 20 deg C, meat thermometer I trust reads 22 deg C. Need to calibrate STC to meat thermometer.

Have mini fridge set up with STC-1000 controller. Held air temp when compared to meat thermometer. Put 7 gal pail with 5 gal 20 deg C water with cover in fridge. Meat thermo probe is in water through air lock hole, STC-1000 probe is taped to side of pail and insulated from ambient temp. Set up has been in place over 24 hours.

Meat thermo displays in whole numbers only and mostly holds at 22 deg C but occasionally fluctuates to 23 deg C, telling me temp is at high end of 22 range. STC display holds at 20, dropping to 19 before heating.

The STC manual was not clear. I assume if F4 (Temp calibration value) is increased 2 deg C the water temp and STC readings will agree when STC is set to 20 deg C.

Question: Is there an expected temp drop of 2 deg C between actual wort temp and the temp STC will read when probe is taped to side of bucket? In other words, would it be better to adjust STC 2 deg C lower knowing the wort temp will be 2 deg C higher and where it needs to be?

 

[arkham_razors]

You need to do an ice bath to calibrate your probe...you are over-thinking it.

 

[arkham_razors]

And yes...many of us (including myself) tape the probe to the outside of the carboy with a little insulation to strike a balance between an over-reacting compressor and a stable wort temp. If you are fermenting an ale, I recommend just going with whatever setup seems OK and tweaking it as you gain experience. Everybody has a different result and it will be trivial to figure out your system after you put any changes in use.

Do you have a Thermopen?

 

[ImperialStout]

Thanks. I did the ice bath with the meat thermometer so I know it is right. Adjusted the STC-1000 off set up 2 deg C and let system sit 24 hours. Now both readings are at 20C.