best fermentation settings for the johnson a419 temperature controller?

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zodiak3000

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I wanted to know what the best settings were for this during fermentation using a mini fridge. I just got it and it seems my temp is not staying stable on the settings I have. I want it at 68F, but seems to be alternating somewhere between 62F-70F. I think its the dIF set to 5, but im not sure. Im sure it would be best at 1 or 2, but I read somewhere this was bad . Should I drop it to 1 or 2 for my mini-fridge fermentation? Here are my settings currently, tell me what i should change-

SP- 68F
dIF- 5
ASd- 12
OFS- 0
SF- 1
 
I've heard that a differential of one to two degrees is bad because the motor is constantly cycling on and off. I would think that 3°F might be a happy medium. It shouldn't kill your motor but at the same time if you're ranging from 65-71°F your beer should stay fairly steady temp-wise. You might want to get a probe thermometer, sanitize it, and stick it right into your beer so you can see how your beer's temp is actually fluctuating since that's what really matters.
 
Is it fluctuating alot because its dangling out in the air of the fermentation chamber (the temp will go up significantly by opening/closing the door), or did you take steps to measure the actual beer temp?
 
im not fermenting yet, just testing it out to see if the temp is accurate in the fridge. I brew on weds. and i will be attaching the probe to the fermenter with bubblewrap for insulation.
 
I've heard that a differential of one to two degrees is bad because the motor is constantly cycling on and off. I would think that 3°F might be a happy medium. It shouldn't kill your motor but at the same time if you're ranging from 65-71°F your beer should stay fairly steady temp-wise. You might want to get a probe thermometer, sanitize it, and stick it right into your beer so you can see how your beer's temp is actually fluctuating since that's what really matters.

They make a device that is part of a stopper that you can stick the probe in. Probably a little easier to keep sanitized and maintain positive pressure with the CO2 blanket. I have wondered how well that works given the obvious lag between the time the compressor kicks in until the wort/beer has dropped enough in temperature to kick it off. I would be very curious to hear other's responses who do it that way. I just bought another freezer on Craig's list that I will use to ferment in.
 
The insulation in a fridge should be pretty good so your beer temp will remain fairly steady. Set the diff to 1 and let it ride.

If you're still afraid of it cycling on too much, keep the diff at 1 for the first 3/4 days of fermentation then you can safely bring the diff back to 5 if you choose. It's those first few days where the temp is crucial to good beer.
 
im not fermenting yet, just testing it out to see if the temp is accurate in the fridge. I brew on weds. and i will be attaching the probe to the fermenter with bubblewrap for insulation.


You have to take into account the thermal mass of the air versus a big carboy of beer.

Open door, air temp will change significantly as it mixed with the warmer air outside.

A carboy full of beer has a much larger thermal mass so its temperature won't change much with opening/closing of the door. Conversely, your refrigerator will have to work/cool for awhile in order to lower the temp of your beer. However, it won't change much once its gotten it down to temp.

You won't see much variability once you stick the probe to the beer (its a fine way of attaching the probe, BTW...I use that method and it works great!). +/- 1 degree as another poster mentioned is fine too.

Good luck!
 
I wanted to know what the best settings were for this during fermentation using a mini fridge. I just got it and it seems my temp is not staying stable on the settings I have. I want it at 68F, but seems to be alternating somewhere between 62F-70F. I think its the dIF set to 5, but im not sure. Im sure it would be best at 1 or 2, but I read somewhere this was bad . Should I drop it to 1 or 2 for my mini-fridge fermentation? Here are my settings currently, tell me what i should change-

SP- 68F
dIF- 5
ASd- 12
OFS- 0
SF- 1

Set the dIF to 1. It's only bad if the compressor continually cycles on and off. That's the point of the ASd which will prevent the compressor starting if it hasn't been off for at least 12 minutes.

-a.
 
I taped a folded up washcloth over the temp probe and to the bucket. Ended up with about an inch of insulation. The bucket changes temperature slowly due to its thermal mass as someone has already pointed out. The freezer is also well insulated so it takes a long time to change temp. Even with a 2 degree diff setting on the thermostat, the motor does not cycle but once half hour or so. That is not going to hurt anything. Most yeast seems to have "happy" range of 5 degrees or more so you should be able to maintain within the range without too much trouble.
 
Set the dIF to 1. It's only bad if the compressor continually cycles on and off. That's the point of the ASd which will prevent the compressor starting if it hasn't been off for at least 12 minutes.

-a.

cool, i think thats what i was looking for. thanks for all the useful feedback as well from everyone else...
 
I'm using my a419 for the first time today to ferment a lager. I have the jumpers set to cut out mode, 1 degree differential, ASD at 12 and setpoint at 48 degrees. However, does anyone know what the temperature offset (OFS) does? I have it set to 0.
 
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