Johnson A419 Questions/Advice (Thanks in Advance!)

[PKisNJ]

Hi there everyone. I have recently jumped back into homebrewing and this time around I wanted to step up my game right from the get-go. Since I am on the second floor of an apt building I have opted to go for a mini-fridge setup w/ a Johnson Controls A419 temp controller. (I know...another Johnson post) I have read about a thousand posts on this controller, but not many are targeted towards mini-fridges.

Questions: What are your settings at if you have a similar set up? I will be fermenting a pale ale (2.5 gallon plastic carboy) and a brown ale (1 gallon glass carboy) at the same time. The optimum fermenting temp for both is within the 65-70 range. Currently my settings are:
SP - 68
Dif - 2
ASD - 10

The probe is in open air at the moment with nothing in the chamber, so when the condensor kicks on at 68 it will swing all the way down to 62 even after the condensor kicks off around 66. How can I ensure I have the beer at proper temperatures?

I have read taping the probe to the side of the fermenter vs. immersed in water vs. thermowell vs. ambient air with a secondary thermometer or fermometer reading the wort temps.

Needless to say this is a long standing discussion but I appreciate any input you can provide!! Thanks again.

 

[DerekJ]

The liquid in the fermenters is not going to experience the same temperature swing as you are experiencing in the ambient air. Once you tape the probe to a vessel full of liquid or submerge it in liquid you will see the temp stay in the range of your settings. Unless you have to make a large initial temperature adjustment. In that case it will probably overshoot the first time but will balance out in a short period of time.

That being said. I set my controller one degree above the temp I want to ferment at. In your case, the optimum range is 65 - 70. I would most likely want to ferment at 65. I would set the controllers SP at 66, the diff at 1 and the ASD at 10 - 15. I find that with the one degree differential the freezer (fridge in your case) spends the majority of its time one degree below the set point.

This information is based on actual working knowledge of my system and may vary in your environment. So take what I have said for what it's worth (not much) and monitor your system to see how it acts.

 

[PKisNJ]

That being said. I set my controller one degree above the temp I want to ferment at. In your case, the optimum range is 65 - 70. I would most likely want to ferment at 65. I would set the controllers SP at 66, the diff at 1 and the ASD at 10 - 15. I find that with the one degree differential the freezer (fridge in your case) spends the majority of its time one degree below the set point.

This information is based on actual working knowledge of my system and may vary in your environment. So take what I have said for what it's worth (not much) and monitor your system to see how it acts.

Thanks for the quick follow up. I will be placing the fermenters into the fridge set up with the probe in the air and monitoring their fermometer strips until they both reach the appropriate temperature. As one carboy is larger than the other if I strapped the probe onto the smaller it one it would cool faster than the larger carboy and visa versa if I placed it on the larger one. After they have reached the good temp I am shooting for, which I have adjusted to about 69 degrees after cross checking the optimal temps for each, I will place the probe onto the smaller glass carboy with the brown ale in it. As the optimal temp for this beer is a little tighter than the pale ale.

I appreciate the insight cheers!