Putting temperature probe in a thermowell

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Good morning,
I have this thermowell for my fermzilla, and was wondering if it is simply a case of putting the probe on my inkbird in to it. It doesn't seem a snug fit - does this matter at all? It just doesn't seem like there's much contact between the thermowell and the probe.
Any help gratefully received.
 
Good morning,
I have this thermowell for my fermzilla, and was wondering if it is simply a case of putting the probe on my inkbird in to it. It doesn't seem a snug fit - does this matter at all? It just doesn't seem like there's much contact between the thermowell and the probe.
Any help gratefully received.
What a great question! It really needs more input, are you cooling or heating? For instance if you are cooling using a cooling coil then it doesn't really matter as I wouldn't think warm air wouldn't enter the thermowell. If you are using a fridge to keep a fermentation stable, then yes I would go down the track of isolating the temperature probe in the thermowell.
But it really does make one think.
 
I filled the thermowell with thermal paste thing, which used for mount heatsinks to processors and stuff like that.
 
A snug fit isn't essential, but will make them temperature probe respond to temperature changes quicker. In practise, this just means you wait a bit longer to get an initial reading.

With a snug fit, there is thermal conduction between the wort, the thermowell and your probe, making the probe the same temperature as the wort pretty quickly.

Without a snug fit, the same conduction happens between the wort and the thermowell, but the thermowell heats/cools the air in the thermowell, and this air heats/cools your probe. It still reaches thermal equilibrium (probe being the same temperature as the wort). You also get thermal radiation to/from the probe/thermowell as well. I have the same setup with my grainfather thrumometer when using a different probe (when I keep the grainfather probe on the grainfather itself) and have found out reaches the correct temp in few minutes.

If there is a big disparity between wort temperature and ambient temperature then in theory, the outside air can mix with the air in the thermowell and throw your reading off, but in a still environment (fridge etc) this will be negligible. You can always seal it with blutac as mentioned above just to make sure.
 
This is my Apollo, jacketed. Working with the Thermentor King Max, it is lagering my Baltic Porter. Couldn't afford to have my cold crash fridge held up for so long so this is the solution. Also would be a solution for those without space for a fermenting fridge, when fermentation is over one could even cold crash with this little 12v unit, after wrap it up and stow it away. Heats and cools so whether winter or summer ideal for the brewers short on space. As above doesn't matter if the thermowell is open or not.
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I installed the same thermowell in the lid of my fermzilla last week. Previously I had placed the temp probe against the side under a foam pad.
Interestingly the temp fluctuations appear much worse with the probe here. Guess it's the thermal mass? Might have to tweak my settings (STC1000 in a fridge with 40W heater element)...

I expected better control but it looks worse than it is, swaying about 1 degree. No idea how accurate my previous method was regards actual wort temp...

Screenshot_20220710-193307_Brewfather.jpg
 

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