Temp control

[Mash Monster]

Strange things are happening in the brew shed !!!
Please bear with me…I have been using fermentation fridges for several years now without issue I ferment in Fermizillas and use inkbird controllers to maintain temperature cooling by the fridge and heating via kegland heat wraps. The probe is placed inside a thermowell. I also use I-Spindels to monitor gravity trends and confirm wort temperature.
A couple of days ago I noticed that the inkbird was reporting 19°c but the I-Spindle was 23.5°c. I checked the temperature of the wort and the I-Spindel was correct . I switched over the Inkbird and all was good . My assumption being the Inkbird was faulty.
Yesterdays brew was placed in the ferm fridge exactly the same set up but with a RAPT controller instead of the Inkbird yeast pitched at 19°c RAPT and I-Spindel reading 19.°C and 19.4°C respectively. On checking the fridge this morning the I-Spindle was showing 23.4°C and the RAPT controller 19°C. The true temperature was 23.8°C .
I can understand the I-Spindle being faulty but the temperature reported is correct .
Anybody got any ideas or have I finally lost the plot

 

[foxy]

Exothermic reaction of the yeast will cause a rise in temperature. I like my ferments to start low, 16-17C , the core of the fermentation can be considerably higher. Best to take the energy produced by the yeast into consideration.
https://byo.com/article/fermentation-temperature-control-tips-from-the-pros/

 

[Sadfield]

Top fermenting yeast producing heat at the top of the wort where the iSpindle sits.

 

[Mash Monster]

Top fermenting yeast producing heat at the top of the wort where the iSpindle sits.

No visible sign of fermentation it’s only been 8 hrs since pitching but very good point that I hadn’t considered as it’s never happened before

 

[RoomWithABrew]

You'll see stratification in the fermenter when the mixing activity of ferment is over.
Move your temp probe to the same height/ level as the iSpindels temp sensor. You should find reading more Similar.
Note if your ispindel is producing heat which happened once for me with a failed gyro you will also get odd readings. Battery life will be terrible as well.

 

[Mash Monster]

You'll see stratification in the fermenter when the mixing activity of ferment is over.
Move your temp probe to the same height/ level as the iSpindels temp sensor. You should find reading more Similar.
Note if your ispindel is producing heat which happened once for me with a failed gyro you will also get odd readings. Battery life will be terrible as well.

Thanks will keep an eye on it