Side by Side fridge with one external thermostat

Discussion in 'Homebrewing' started by Ten_SeventySix_Brewhouse, Nov 14, 2016.

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  1. Ten_SeventySix_Brewhouse

    Ten_SeventySix_Brewhouse Zealot (744) Jul 20, 2016 Indiana

    I currently have a side by side fridge in which I am storing my bottled/canned beer. The freezer compartment is virtually empty, and aside from occasional overflow from the kitchen fridge, always will be. I'm planning on meeting a guy on Craigslist who is also selling a Johnson Controls single thermostat. I was thinking about buying it but am wondering how much use it would be to me, given the type of fridge that I have.

    I understand the the freezer part is usually regulated, and the fridge is basically cooled by opening/closing dampers in the middle divider. I currently have bottles I need to store cold, would like to be able to ferment at lager and ale temps, am thinking about kegging in the future, and would like to be able to later.

    My basic questions:
    - Could I do all of the above with the equipment available to me? (Not necessarily all at the same time.)
    - What kind of temperatures can I expect in the fridge if I keep the freezer at lagering/serving temperatures?
    - Will the built in (digital) temp control help control the fridge temperature if I put the probe in the freezer, or would that be rendered useless?

    I'm just looking for a solution here that doesn't require a lot of cutting or expense.
     
    #1 Ten_SeventySix_Brewhouse, Nov 14, 2016
  2. PortLargo

    PortLargo Pooh-Bah (1,831) Oct 19, 2012 Florida
    Pooh-Bah

    a) This will be difficult to accomplish without a lot of trail and error. The subject comes up from time to time . . . I'm not aware of anyone* posting a "here's the solution" reply.
    b) I do just the opposite of your proposal; I ferm in the mid 60s on the fridge side, I place buckets of water in the freezer section and they are solid ice during hot weather (compressor runs more due to cool air escaping). At moderate outside air temps the buckets of water stay liquid. This isn't what you are asking but shows the dynamics involved while trying to nail down your temps, i.e. lots of variables.
    c) Useless. It will accurately control whichever side you place the probe, but your dampers and door seals set the temp for the other section.

    BTW, not trying to besmirch a Johnson controller, but you can buy a cheap Inkbird for under 20 bucks (Amazon) that seems to work pretty nicely (get 'em before we set tariffs on China!).

    *In the Home Bar forum one poster claimed to have modified a raspberry pi to accomplish this feat . . . but on searching, he has been purged from BA.
     
    #2 PortLargo, Nov 14, 2016
    billandsuz and PapaGoose03 like this.
  3. PapaGoose03

    PapaGoose03 Grand High Pooh-Bah (6,057) May 30, 2005 Michigan
    BA4LYFE Society Pooh-Bah

    I'm like @PortLargo and put my probe into the fridge section. The built-in thermostat for my fridge stopped working long ago and fortunately is stuck in the On position. I keep the external thermostat set at 45-50 for my 'cellared' beers, and bump it up to 50-55 when fermenting a lager, or down to 32-35 when lagering. During all three settings the freezer section stays below freezing for me so that I can keep my ice packs for my coolers. or other items that need to be frozen, and they always seem to stay frozen, although I don't think it is zero degrees. So it's a matter of playing around with your dampers to get a temp where you want it for each side of the appliance at the same time.

    Additional point #1: There is only one cooling unit for the entire appliance, thus there is no way that you can have an external thermostat for each side unless you also have some kind of an automatic damper control that somehow works in combination with the external thermostat.

    Additional point #2: You have to use an external thermostat to be able to have a 50-55 temp in the fridge section for lager fermenting because I don't think any fridge's built-in thermostat has a high enough setting to allow the fridge to attain that temp range. I don't know the exact temp number, but a fridge is designed to operate at around 40 degrees and below or you'd have spoiled food.
     
    #3 PapaGoose03, Nov 14, 2016
  4. Ten_SeventySix_Brewhouse

    Ten_SeventySix_Brewhouse Zealot (744) Jul 20, 2016 Indiana

    Right, so that leads to a couple of ideas:

    1) Set the freezer, via external thermostat, to lagering temps (32-40 F). The fridge compartment would just be along for the ride, in that case, completely unregulated. I wonder what the ambient temperature would be. Would the dampers still function in accordance with the set temperature of the INTERNAL thermostat, at least while the compressor was running, or would they stay perpetually shut/open?

    2) Cut a hole between and place a fan there to bring cold air into the fridge space. This would require a dual thermostat: one for the compressor and one for the fan. Taking this idea further, is completely removing the middle divider so that you can have one temperature in a large compartment feasible? I've seen it done, but I have to wonder if most fridges have "stuff" in that wall you would need to worry about cutting.
     
    #4 Ten_SeventySix_Brewhouse, Nov 14, 2016
  5. PapaGoose03

    PapaGoose03 Grand High Pooh-Bah (6,057) May 30, 2005 Michigan
    BA4LYFE Society Pooh-Bah

    Since the freezer is the primary recipient of the cold air, and since you are likely going to be going thru a trial-and-error process, don't forget to try it by placing the probe in the freezer as well as the fridge section. That may help give you some additional control between fermenting vs. lagering temps at the same time.
     
    #5 PapaGoose03, Nov 14, 2016
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