Using a Temp Probe in Fermenter - how to keep it airtight

Discussion in 'General Brewing Discussions' started by BattleBuddy, Jun 8, 2020.

  1. BattleBuddy

    BattleBuddy New Member

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    Hi Beer People

    I recently bought a unit to help me maintain the correct temp of my fermentation bucket.
    Just a basic one with a probe on a wire that you then connect to the power supply of your heat mat.

    But i found that with the probe wire going in to the fermenter i was not able to achieve an airtight seal, the bucket lid would not seal.

    How do other people get around this problem?

    Thanks in advance
     
  2. Bubba Wade

    Bubba Wade Well-Known Member

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    Two options, both of which avoid putting your probe in the fermentation bucket.

    The first is to install a thermowell in the lid of your fermenter. This keeps the probe from directly contacting the liquid. These are available from several different supply shops. Sometime you can find them with a stopper that has both the thermowell and a place to put your airlock.

    The other option is to tape the probe to the outside of the bucket. If you have a heating mat that you can set the bucket on, try taping the probe to the side of the bucket about halfway up. You need to insulate over the probe. This works reasonably well, but will not be as accurate as the thermowell.
     
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  3. jmcnamara

    jmcnamara Well-Known Member

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    Followup question I've been meaning to look into. I've got the thermowell with the airlock stopper, but it's too small for my carboy. I've wrapped some aluminum foil around it to sort of wedge it in place, but I'm afraid its going to slip into the carboy one day. Any ideas?
     
  4. BOB357

    BOB357 Well-Known Member

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    Depends on what size stopper you need Joe. Common sizes for two holers are 6 1/2 and 10. You can get any size undrilled stopper and drill it yourself if need be.
     
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  5. Craigerrr

    Craigerrr Well-Known Member

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    Here is what I use, you could just drill the appropriate size hole in your lid for this, accepts the thermowell tube, as will as a standard airlock. The probe on the inkbird slides right in. The probe is not meant to be immersed, important to use the thermowell.
    Hope this helps.
    thermowell stopper.JPG
    inkbird.JPG
     
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  6. Craigerrr

    Craigerrr Well-Known Member

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    I had that issue with carboys, total PITA.
    These are an option...
    air lock in one, thermowell in the other...
    I used these for pressure transfers when I had carboys.
    FWIW - Carboys are evil, they are extremely dangerous, please be careful.
    You don't want to have an accident and then a beer for the damage it caused...
    Case in point, My "Bloody Finger" Cranberry Chocolate Stout
    carboy cap.JPG
     
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  7. Craigerrr

    Craigerrr Well-Known Member

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    How I currently utilize that silicone two hole bung, see post number 250 in the following thread.
    I used a piece of vinyl tube folded over for the second hole, but I now have a proper plug in the extra hole.
    https://www.brewersfriend.com/forum/threads/show-your-diy-projects.1026/page-13
     
  8. Nosybear

    Nosybear Well-Known Member

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    I just tape my probe to the outside of the carboy. Used to do the thermowell thing but since I'm using an upright freezer for a fermentation chamber, the temperature would yo-yo too much before stabilizing. So now, a bit of tape, a bit of batting and voile! Works like a champ.
     
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  9. Craigerrr

    Craigerrr Well-Known Member

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    That works too, and I did the same with carboys for a time as well. My Speidels are barrel shaped and my probe is long, I had to come up with something.
     
  10. Mark Farrall

    Mark Farrall Well-Known Member

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    Gaffer tape and a few centimeters off my yoga mat around the probe taped to the side of my fermenter. Works pretty well. I've got a tilt inside most of my batches so I can see there's around a 1C difference between beer temp and probe on the outside.
     
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  11. jmcnamara

    jmcnamara Well-Known Member

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    Ah cool, I've got 2 of these on racking canes for that exact reason. I'll have to fiddle with it on the next batch
     
  12. BattleBuddy

    BattleBuddy New Member

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    Thanks for all the awesome replies, beer people are the best people.
    I have ordered a thermo well and until that arrives i will stick probe to side of bucket with some insulation.
    Can't believe i was dumb enough to just drop it in there.
     
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  13. Nosybear

    Nosybear Well-Known Member

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    We've all been there. I was using a thermowell and quit due to problems mentioned above.
     
  14. 4Bentley

    4Bentley Active Member

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    I put the thermocouple next to the carboy and then mold a kneaded eraser (from an Art store) around the back of it followed by a piece of tape. It gives a good seal and insulates from the outside air. The kneaded eraser is like plumbers putty but doesn't stain or leave a residue on the carboy.
     
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  15. Craigerrr

    Craigerrr Well-Known Member

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    Clever!
    When I taped my probe to the outside of my evil, injury inflicting carboys, I cut up some reflective to nestle the probe in and taped that to the evil glass flesh slicing monsters...
     
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  16. 4Bentley

    4Bentley Active Member

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    I'm Sorry. So far I haven't been injured by glass, so I will continue. This would also work on steel. Someday I might work up to steel.
     
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  17. Craigerrr

    Craigerrr Well-Known Member

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    Don't apologize, I was making light of it, but please do be very careful with those big glass bottles
     

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