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Author Topic: Chest Freezer/Temperature Control  (Read 13284 times)

Offline Erik_Mog

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Re: Chest Freezer/Temperature Control
« Reply #15 on: June 02, 2016, 07:39:07 am »
For 5, either setting should work just fine for fermentation.  To the OP: good investment.  Fermentation temp control really helped me make better beer.

That's what I am hoping for.  I know my temperature control was the biggest of my blunders on that first batch.  All of the other things were procedural things that are easily corrected.  I had hoped for a much better first batch, but I can use it as a learning tool to make future beers a lot better.

As far as the freezer goes now, I have been monitoring it with 5g of water in a carboy with the sensor taped to the outside under foam.  I have it set to 65F with a 1F delta.  The compressor comes on when the water gets to 66F, and shuts off at a sensed temp of 65F.  I have yet to see it go over the 66F mark and the coldest I have seen on any of my checks has been 64.5F  I have no idea what the ambient air temp in the freezer is at this point, as I am only looking at the temp of the liquid. 

For a test last night, I set the freezer control to its warmest setting, and this morning the test water was still at a steady 65F-66F, with the lowest temp being 64.5F.  This freezer has settings 1-7 on it's thermostat, and according to the manufacture, a setting of 4 should maintain a temp of 0F.

Just from my observations, it doesn't seem to matter where the freezer itself is set to maintain a temp of ~65F in the liquid for fermentation.  I have not done a simulated cold crash with the freezer set at different settings, but I would guess for that, I would have to have it set to at least the 4 setting.

Somehow I do get the feeling that I am overthinking this to a degree, but that's how my crazy mind works.  As a Chef by trade, I want to know what is happening and why.
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Offline JT

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Re: Chest Freezer/Temperature Control
« Reply #16 on: June 02, 2016, 07:46:44 am »
For 5, either setting should work just fine for fermentation.  To the OP: good investment.  Fermentation temp control really helped me make better beer.

That's what I am hoping for.  I know my temperature control was the biggest of my blunders on that first batch.  All of the other things were procedural things that are easily corrected.  I had hoped for a much better first batch, but I can use it as a learning tool to make future beers a lot better.

As far as the freezer goes now, I have been monitoring it with 5g of water in a carboy with the sensor taped to the outside under foam.  I have it set to 65F with a 1F delta.  The compressor comes on when the water gets to 66F, and shuts off at a sensed temp of 65F.  I have yet to see it go over the 66F mark and the coldest I have seen on any of my checks has been 64.5F  I have no idea what the ambient air temp in the freezer is at this point, as I am only looking at the temp of the liquid. 

For a test last night, I set the freezer control to its warmest setting, and this morning the test water was still at a steady 65F-66F, with the lowest temp being 64.5F.  This freezer has settings 1-7 on it's thermostat, and according to the manufacture, a setting of 4 should maintain a temp of 0F.

Just from my observations, it doesn't seem to matter where the freezer itself is set to maintain a temp of ~65F in the liquid for fermentation.  I have not done a simulated cold crash with the freezer set at different settings, but I would guess for that, I would have to have it set to at least the 4 setting.

Somehow I do get the feeling that I am overthinking this to a degree, but that's how my crazy mind works.  As a Chef by trade, I want to know what is happening and why.
You aren't over thinking it.  "Measure twice, cut once" as the saying goes.  It's good to do trial runs with new equipment before you have a half day's labor depending on it to work correctly.  The main difference between your water test and the actual fermentation will be the heat created by fermentation, so your freezer will cycle more often.   

Offline kramerog

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Re: Chest Freezer/Temperature Control
« Reply #17 on: June 02, 2016, 08:35:29 am »
My point is about the temperature of the freezer when the fermentation temp controller turns the freezer off.  Do you want the freezer to be 40*F, 20*F, 0*F, etc?  If it is 0 *F, the fermenter temp will drop significantly below the desired temp.  The OP says it drops 3 *F below his setpoint.   Of course the temp undershoot also depends on the mass of the freezer versus the mass of the beer.

Offline Visor

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Re: Chest Freezer/Temperature Control
« Reply #18 on: June 02, 2016, 10:58:11 am »
   I don't think you are over thinking this, some of the other respondents may be. You have 2 thermostats, both of which "make' when the temperature of the medium they are measuring exceed their set point. The freezer thermostat is sensing the temp of the air in the freezer, the other controller is primarily sensing the temp of the outside of your fermenter. Since the compressor will only run when both controls are calling for cooling one of the controls is redundant, but the two are NOT working against each other. The reasons for adding the extra controller are twofold, you are only concerned with the temp of the beer in the fermenter and not the air temp in the freezer, and freezer temp controls, especially in inexpensive chest freezers, are not capable of maintaining the temperature range you desire. Since both controls must be calling for cooling for the compressor to run, and you want to control this with your add on, then you want the freezer temp control to always be calling for cooling. I doubt that it really matters what you set the freezer temp control at as long as it is in the "on" position. Most freezers even on the highest temp setting are below 30 degrees, but you can determine that rather easily before you put valuable beer in there.
   I think you might be better off once you have fermenting beer in there with the sensor NOT controlling compressor operation off of the temp of the outside of the fermenter, but rather the actual air temp of the freezer. Remotely monitor the temp in your fermenter AND the temp inside the freezer, and lower the set point on your controller, if necessary, by the difference between actual beer temp and your desired temp. I think you'll get less overshoot and temp fluctuation this way. I will spare you all a long, drawn out attempt to explain my reasoning here.
   Good luck.   
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Offline OD600

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Re: Chest Freezer/Temperature Control
« Reply #19 on: January 06, 2017, 01:46:47 pm »
1) A properly insulated probe attached to the carboy will read within 0.5F of beer temp; use that as your baseline, do it the same way every time, and adjust from there. 65 via your process  will not be the same as 65 via someone else's (don't worry, you'll still make great beer)

2) 1 degree F delta is fine, even 2 is probably OK. I set mine to 1 when I'm fermenting and 2 when conditioning (to minimize compressor cycles)

3) I don't know the InkBird, but most controllers have a setting for this; if yours doesn't, I'd set it a little above so it doesn't overcool too far; don't want to shock your yeast

4) Probably won't hurt, but in most cases probably unnecessary, especially in a 76F room

5) Coldest, but it won't really matter since your controller will turn it off before the freezer thermo will do anything (which is good)

6) Should be. You can always cram the airlock a little further down if you need a little space; Worst case blowoff might help depending on how much room it takes for the tubing to make a 180 without getting pinched; I just crammed the airlock down a little farther

Question about 2) response above: Do you have your temp probe in the air or in a container with thermal mass? I moved my probe to a half gallon container with a thermowell. The probe is placed approximately in the middle of half gallon of water that's in there. I have a chest freezer/kegerator. I started with a 2 deg differential but have since moved to a 1 degree differential. My target is 37 degrees for conditioning. Hope I'm not burning out the compressor that much more quickly. The cycling seems fine so far.
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Offline blair.streit

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Re: Chest Freezer/Temperature Control
« Reply #20 on: January 06, 2017, 01:57:27 pm »
1) A properly insulated probe attached to the carboy will read within 0.5F of beer temp; use that as your baseline, do it the same way every time, and adjust from there. 65 via your process  will not be the same as 65 via someone else's (don't worry, you'll still make great beer)

2) 1 degree F delta is fine, even 2 is probably OK. I set mine to 1 when I'm fermenting and 2 when conditioning (to minimize compressor cycles)


Question about 2) response above: Do you have your temp probe in the air or in a container with thermal mass? I moved my probe to a half gallon container with a thermowell. The probe is placed approximately in the middle of half gallon of water that's in there. I have a chest freezer/kegerator. I started with a 2 deg differential but have since moved to a 1 degree differential. My target is 37 degrees for conditioning. Hope I'm not burning out the compressor that much more quickly. The cycling seems fine so far.

In my conditioning fridge I just leave it dangling in the air, which is one of the reasons I went to 2F delta. I wouldn't overthink it - your solution seems more than adequate.


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