Fridge temp controllet probe placement

[mike_bkk]

Hi everyone,
I am new to brewing and my first brew will be with a Mr. Beer kit. I have an old fridge and a temp controller. I was planning to tape the probe on the LBK with some foil tape. My controller has 2 outlets so I can add a heating pad if needed (don't think it will be)
Is it best to attach the probe to the fermenter in some manner like this or should it just measure the ambient air in my fermentation chamber (old fridge )

 

[doug293cz]

Taping the temp probe to the LBK, with a little insulation (folded wash cloth or paper towel is sufficient) on top of the probe (and probe in direct contact with the LBK) works quite well. The insulation makes the probe more sensitive to the beer temp (which is what you want to control during fermentation), without isolating it completely from the fridge air (which helps keep the air temp from getting too far away from the beer temp, which could cause temperature oscillations.)

Brew on

 

[A1sportsdad]

Your best bet is to put a thermowell into the wort and drop your temperature sensor in there. You really want to measure the temperature inside the fermenter. I try to angle it to get towards the center. Should not have issues with oscillation as it takes a hell of a lot of air mass to cool the wort so I do not expect your fridge to cycle off and on much at all with the probe inside the fermenter. It would cycle much more with the probe outside the fermenter.
I have never needed a heat source. There’s enough heat produced with fermentation that heat is not necessary.