Author Topic: Monitoring freezer fermentation temps  (Read 1453 times)

Offline Keith G

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Monitoring freezer fermentation temps
« on: August 27, 2014, 09:01:02 PM »
I had a newbie question about fermentation control in a chest freezer.  How do you monitor the wort temp in buckets? 

I guess you could use a fermometer, but wouldn't that mean picking the bucket up to check it by lifting it out of the freezer?  This would greatly increase your chances of disturbing the wort during fermentation, right?

I guess the same question could be asked when using a cooler with water and froZen water bottles to chill.


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Offline denny

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Re: Monitoring freezer fermentation temps
« Reply #1 on: August 27, 2014, 09:17:43 PM »
I had a newbie question about fermentation control in a chest freezer.  How do you monitor the wort temp in buckets? 

I guess you could use a fermometer, but wouldn't that mean picking the bucket up to check it by lifting it out of the freezer?  This would greatly increase your chances of disturbing the wort during fermentation, right?

I guess the same question could be asked when using a cooler with water and froZen water bottles to chill.


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I guess it depends on the size of the freezer and the orientation of the bucket.  I can see the fermometers just fine in mine.  And the agree exactly with the temp on my Ranco.  Even when I used the water tub method, the fermometers were above the water line and easily visible.
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Offline narcout

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Re: Monitoring freezer fermentation temps
« Reply #2 on: August 27, 2014, 09:22:39 PM »
Do you have a temperature controller like this (or similar)?

http://www.northernbrewer.com/shop/johnson-controls-a419-digital-temp-controller.html

You can insulate the probe and tape it to the side of the bucket or use a thermowell.  You might have to make some modifications to your bucket lid though.

https://www.midwestsupplies.com/stopper-thermowell.html?utm_medium=feeds&utm_source=google&gclid=CPLzsc-utMACFUFufgodZoMAFQ

You could also drill a hole in the side of your bucket and install a thermowell similar to this one.

https://www.brewershardware.com/6-Weldless-Thermowell.html

Using a fermometer to get a second reading isn't a bad idea, especially if you are taping the probe to the side of the bucket.  If you position it right, you should be able to read it without removing the bucket.
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Offline David Lester

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How to calculate the wort temp without a thermometer
« Reply #3 on: August 27, 2014, 09:57:50 PM »
If you have a temp controller on the freezer, the wort will be the same temp after it stabilizes for approximately 6 to 12 hours. Within 24 hours of pitching your yeast, the temp on a 5 gallon should increase approximately 3°F to 5°F depending on yeast activity.

Therefore, reduce the freezer temp by 3°F and your wort temp will be within a few degrees of your desired fermentation temp. That way you don't need to check the wort temp.

Offline kramerog

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Re: Monitoring freezer fermentation temps
« Reply #4 on: August 28, 2014, 03:06:23 AM »
This would greatly increase your chances of disturbing the wort during fermentation, right?


I wouldn't be the least bit concerned about disturbing the wort other than possible sucking the liquid in your fermentation lock into your wort.  Wort doesn't have any feelings.

Offline wingnut

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Re: Monitoring freezer fermentation temps
« Reply #5 on: August 28, 2014, 11:57:36 AM »
I wouldn't be the least bit concerned about disturbing the wort other than possible sucking the liquid in your fermentation lock into your wort.  Wort doesn't have any feelings.

+1   

Though lifting is a pain.  Get an inspection mirror from the autoparts store...smalll 3x2inch mirror on a stick.... that way you can monitor the temp and save your back!
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Offline Jimmy K

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Re: Monitoring freezer fermentation temps
« Reply #6 on: August 28, 2014, 01:19:03 PM »
I guess you could use a fermometer, but wouldn't that mean picking the bucket up to check it by lifting it out of the freezer?  This would greatly increase your chances of disturbing the wort during fermentation, right?
Attach the fermometer upside down and look at it with a mirror. - But I would go with the tape and insulation route with an inexpensive probe thermometer.
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Offline mugwort

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Re: Monitoring freezer fermentation temps
« Reply #7 on: August 28, 2014, 06:38:49 PM »
IR temp gun.  Very handy.
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Offline Stauffbier

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Re: Monitoring freezer fermentation temps
« Reply #8 on: September 15, 2014, 09:36:34 PM »
I built my chest freezer fermentation chamber with a STC-1000. For the first couple of months I was often suspicious as to whether the temp on the display was true to reality, so I would often pull a sample and check the temp. After doing that a number of times, I determined that the temp controller was reading accurately. Since then I don't really monitor the temperature. Although, every once in a long while I will check the temp of a sample to make sure that the temp controller is still working properly.  FWIW, I also tape the probe to the side of my fermenters with a thick piece of insulation.

Offline tommymorris

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Re: Monitoring freezer fermentation temps
« Reply #9 on: September 16, 2014, 12:46:06 AM »

I built my chest freezer fermentation chamber with a STC-1000. For the first couple of months I was often suspicious as to whether the temp on the display was true to reality, so I would often pull a sample and check the temp. After doing that a number of times, I determined that the temp controller was reading accurately. Since then I don't really monitor the temperature. Although, every once in a long while I will check the temp of a sample to make sure that the temp controller is still working properly.  FWIW, I also tape the probe to the side of my fermenters with a thick piece of insulation.

Did you measure the temp during high krausen also? I have checked my temp controller against the actual wort temp when not fermenting but not when fermentation is active. I connect the probe the same way as you and can confirm there is no difference between temp on the controller and measured temp when fermentation is not active.

Offline Stauffbier

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Re: Monitoring freezer fermentation temps
« Reply #10 on: September 16, 2014, 02:17:28 AM »
Did you measure the temp during high krausen also? I have checked my temp controller against the actual wort temp when not fermenting but not when fermentation is active. I connect the probe the same way as you and can confirm there is no difference between temp on the controller and measured temp when fermentation is not active.

Yeah, I checked at various stages of fermentation. During high krausen the beer would sometimes be 1-2 degrees hotter, so I set my controller a bit lower for the first couple of days. Then after a few days I raise the temp a little, and everything stabilizes.

Offline tommymorris

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Re: Monitoring freezer fermentation temps
« Reply #11 on: September 16, 2014, 02:18:35 AM »

Did you measure the temp during high krausen also? I have checked my temp controller against the actual wort temp when not fermenting but not when fermentation is active. I connect the probe the same way as you and can confirm there is no difference between temp on the controller and measured temp when fermentation is not active.

Yeah, I checked at various stages of fermentation. During high krausen the beer would sometimes be 1-2 degrees hotter, so I set my controller a bit lower for the first couple of days. Then after a few days I raise the temp a little, and everything stabilizes.
Cool. I need to try that myself. I have always wondered how far off the temp is at peak.