Lager temperature control

Discussion in 'General Brewing Discussions' started by jeffpn, May 13, 2016.

  1. jeffpn

    jeffpn Well-Known Member

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    When I lager in my chest freezer, I set the controller to 55°, and I also have ferm wrap wrapped around my carboy. This is the best way that I know how to stabilize the temperature as well as possible. When the freezer kicks on, it stays on until my beer reaches 55°, but the cold air in the freezer continues to chill it to the point where the fermwrap turns on. Even after the the ferm wrap turns off, there's still enough cold air to chill the beer again, causing the ferm wrap to turn on a second time before the freezer cycles again.

    Is such precise temperature control necessary during the lagering (not fermenting) process? Maybe all the ferm wrap does at that point is cause the beer to warm faster than it otherwise would, resulting in more freezer run time? Maybe it'd be easier not to use the ferm wrap when I'm lagering? I mean, does it really matter if I set the controller to 34°, but it chills to 32° because of all of the cold air, and then doesn't kick on again until it hits 35°? Maybe the freezer would cycle less if I wasn't heating the beer as well. What say you?
     
  2. Ozarks Mountain Brew

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    don't use any heat source, it just kicks on and off too much, just use the freezer alone and no it shouldn't matter
     
  3. Hogarthe

    Hogarthe Well-Known Member

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    lagering it won't need to be warmed. it doesn't need to be exact. if it cools down a degree or 2 more it won't hurt any.
     
  4. Nosybear

    Nosybear Well-Known Member

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    Precise temperature control (within reason) is important to primary fermentation of lagers. It's not so important to keep things within a degree or so once lagering begins. There's no real science to lagering, more art, when it's done, it's done, just keep it pretty cold and it will be fine.
     
  5. jeffpn

    jeffpn Well-Known Member

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    I don't know why I never thought of foregoing the fermwrap for the secondary. I think I'll try lagering without it for a few batches.
     
  6. artbreu

    artbreu Member

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    Lagering was done in caves traditionally where you could imagine there being small fluctuations of temperature not only day to night but day to day and season to season. If you are trying to reproduce a brew to exact standards, it's more crucial, but to just make a great lager? Totally not worth giving it a second thought.
     
  7. jeffpn

    jeffpn Well-Known Member

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    Actually, our local cave is 54° year round.
     
  8. Nosybear

    Nosybear Well-Known Member

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    The temperature in caves does tend to be very stable - I believe Mammoth Cave in Kentucky varies by less than a degree year round. I've started rigorous temperature control even for my ales and it makes a HUGE difference in the outcome, much more than a recipe reformulation (assuming I'm not trying to use hops in quantities that nuke your tastebuds). To control temperatures I use an Inkbird 308 controller (two-stage) with the temperature probe in the beer, a refrigerator connected to the cool side and a 40-watt light bulb (incandescent so it doesn't emit UV and cause skunking) on the warm side. This keeps my fermentation temps to +/- 1 degree F (0.3 C). Late in the fermentation, I start warming the beer by a degree or so a day to burn off any diacetyl or other fermentation by-products. The end result is clean, highly attenuated beer. I've found this control to be the number one contributor to the end quality of my beers.
     
  9. Gunnibrewer

    Gunnibrewer New Member

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    NosyBear, how do you get the temp probe into the beer without breaking seal?
     
  10. jeffpn

    jeffpn Well-Known Member

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    Here's how I do it. I pinched and soldered a copper tube. The temp probe is inside of it.
     

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  11. Ozarks Mountain Brew

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  12. Gunnibrewer

    Gunnibrewer New Member

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    I see! Thanks guys.
     
  13. Nosybear

    Nosybear Well-Known Member

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    Very similar setup: I use a Speidel 30 liter fermentor. I drilled a hole in the top, put a grommet in it and inserted the long probe through the grommet into the beer. I don't take it out, instead have one of the smaller probes used with thermowells when I need to control just the temperature of the refrigerator. Cleaning and sanitation are easy: I sanitize the probe when I sanitize the fermentor. Would provide pictures but I'm currently taking a brain break at work....
     

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