Germ Chamber Temp Control

[Banks2012]

Hello all,
New to home brewing here and just finished making my first batch with from an extract kit and put it into my fermentation chamber in a plastic bucket, which is a chest freezer and ferm wrap plugged into the WiFi Inkbird 308. I drilled out and installed a Thermowell in the center of the bucket lid at about a height that will read the temp in the center of the wort. The issue I seem to be having is overshooting both the heating and cooling by as much as 4-5 degrees. I’m assuming this is because by the time the temp changes all the way on the center the outsides have gotten much warmer or colder. Does anyone have any suggestions or recommendations to correct this issue? Thank you in advance!

 

[Banks2012]

Here is the temp chart since I moved to ferm chamber

 

[lashack]

What is your heat difference and cool difference set to (usually Hd and Cd)? I have my temp control set to 1F on both heat difference and cool difference. Meaning when it recognized 1F temp off, it will power on heat or cool until the target temp is hit. Once the target temp is hit, the unit turns off.

If your difference is set too narrow, let's say 0.5F, it's going to constantly be teeter-tottering back and forth and will have massive swings. Try and adjust the heat and cool difference and see if that helps.

Also, 95% of the beers I brew never need heat. Only cooling feature.

 

[Banks2012]

Thank you for your response. After some experimenting I discovered that I had the threshold set too high at 3 degrees. What was happening was the heater or freezer would run too long and causing it to overshoot. I adjusted to just a one degree difference up or down and now stay pretty consistent betwee 66.7 degrees and 69.

 

[lashack]

That’s great you got it figured out!

 

[Kickass]

I’m not sure what your ambient temps are but a heating element may be unnecessary and causing big swings. Or vice versa. If you can get away with one temp spice, heat or cool, that will eliminate a lot of your issues.

 

[JP_BeerFan]

For tuning a temp chamber, it can be useful to have some logging of the air temp as well, if you have a way to do that. They become two rather different things when you have your control attached to a large thermal mass, i.e. a nice batch of brew. Its harder to see whats going on, inside that big mass.

I have a separate Inkbird monitor thermometer (was on offer here a while back, Thanks again!) that I set in there and thereby monitor both.

Was easy then to see how fast the heating/cooling rate was, which told me how much it helps to have a small fan circulating air in a fanless dorm fridge, or that I had more heating power than I needed, for instance. I also had (is 3deg the Inkbird controller's default setting?) a large threshold that I brought down to 1deg, and that improved control a lot.

25W lightbulb with a tin can over it in my small dorm fridge is apparently twice as strong as the cooling power. ;-) When I get back into things, will try a 14W coffee cup warmer I found instead...

 

[Deadalus]

...

25W lightbulb with a tin can over it in my small dorm fridge is apparently twice as strong as the cooling power. ;-) When I get back into things, will try a 14W coffee cup warmer I found instead...

Mini-fridges don't use much power, about 50-100 watts. The room is typically warmer too.