Fermenting Fridges! (or more importantly, how to make one)

Discussion in 'Geek Grog & Homebrew' started by Embercide, Jan 10, 2013.

  1. Embercide

    Embercide Member

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    Has anyone made one before? I found this FridgeMate that looks simple enough: http://mashmaster.com.au/p/365439/fridgemate-mkii-digital-temperature-controller-kit.html
    Installation instructions: http://mashmaster.com.au/UserFiles/2321-Files/File/FridgeMateMKIIColour.pdf

    Correct me if i'm wrong but it looks like it sits in between the mains and condenser and simply turns the condenser off when it gets cold enough? That sounds like it comes with the added benefit of saving money on power ;)

    Come wintertime would I need some sort of heating element in the fridge as well or should the sealed fridge maintain the internal temp even if outside temps are 15-20C colder?

    Or is there a better way that i'm not considering?
     
  2. Quadbox

    Quadbox Member

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    That's right, it plugs into the mains socket, then the fridge plugs into it. and it simply turns the fridge on and off. You can just run the temp probe through the door and bluetack it to your fermenter, or similar.

    There's a whole bunch of similar models that all do the same job, differences tend to mostly be whether they control both a heating and a cooling circuit, or just one circuit, and what current they're rated to. The cheapest atm are the STC-1000 models, which're typically about $30 and have both a heating and cooling circuit, 10amp. If you google stc-1000 you'll find detailed instructions on how to set them up. I've got two of them, and one of the fridgemates you linked. Had a second fridgemate but it met with an accident last year (some idiot spilled beer on it when it wasnt in a box :p)

    Considering you're in brisbane, you'll probably never need heating. bear in mind fermentation produces *some* heat, and your fridge is pretty well insulated. If it's 12C outside for 6 hours at night it's not likely to drop your brew temps much below 17, so it's a non-issue. if, however, it's colder than that then you can use a dual circuit controller like the above, and run a brew-belt or heat pad or heat lamp or whatever else off of it

    It's a good idea, btw, to build a sturdy plywood shelf for the base of the fridge. a full fermenter's going to break a plastic or glass fridge shelf eventually

    BE VERY CAREFUL DOING THE WIRING. Technically speaking only a licensed electrician should be doing it, though I've wired all my own. The parts you'll need to do a neat job are a plastic box (like a jiffy box from jaycar say), a couple of cable glands, a 3-way screw terminal (they come in 12-way strips, you cut off 3 of them) and a cheap extension cord to cut up (or two if you're putting a heating circuit in there too)

    EDIT - A good guide someone did ages ago about wiring up an stc-1000: http://www.aussiehomebrewer.com/forum/index.php?showtopic=66428
     
    Last edited: Jan 10, 2013
  3. scon

    scon Member

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    Yep, I've got an STC-1000 hooked up to a chest freezer and it works wonders, let me know if you need a hand with it.
     
  4. Echo Man

    Echo Man Member

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    I run the fridgemate on my chesty, it's great. I run another on my fermentation fridge. This allows close control of brew temps and also allows me to chill in the fermenter before kegging - this has a big effect on clarity IMO.

    I've also used a fridgemate in heating mode to control a bar heater in my toddlers room during winter. Having it at 20 deg every night helps them sleep through and hence helps us sleep!

    There would be heaps of temp control info on AHB and I know there are a couple of specific fridgemate threads.
     
  5. OP
    OP
    Embercide

    Embercide Member

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    Cheers guys :thumbup:
    It seems like such a simple thing, it amazes me there isn't simply a pre-made box that you plug the fridge into and the other end into the GPO, no wiring required.

    Regarding the temp probe, would you normally just close the door on the wire and let the door seal do its thing, or would you go to the effort of drilling through the fridge wall and sealing it up with something?

    I've also got a chest freezer in the shed sitting there doing nothing, hasn't been turned on for a couple of years
     
  6. Quadbox

    Quadbox Member

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    I use one on my actual beer/keg fridge as well, just for more definite control than the inbuilt thermostat gives

    EDIT - Embercide I've seen fully put together good to to boxes as you described, they were all above $100. The actual controller units themselves are a dime a dozen mostly because they tend to get embedded in commercial freezers (which are in place assembly jobs typically, because the compressor/condenser is a seperate unit to the fridge. usually outside the building). So commercial refridgeration guys buy them by the hundreds, and wire each one as appropriate
     
    Last edited: Jan 10, 2013
  7. Echo Man

    Echo Man Member

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    You CAN drill through the side of a fridge but generally I wouldn't. Modern fridges usually have cooling lines running through the walls so if you can avoid them somehow you're OK. Bust one and you're f&%ked.

    I've drilled through the side of my old bar fridge - it has the old style chiller plate at the top and the fridge is just an insulated box. With the chesty I, removed the lid, fitted a timber collar, fitted the lid to the collar and then drilled through the collar to mount taps and run the probe.

    Otherwise you can of course just sandwich the wire through the door seal. A slit in the seal will allow you to squeeze it apart and run the wire through and get a better seal. When the wire isn't there the seal can be pushed back together or even super glued back together if you're done with the temp control.
     
  8. mmBax

    mmBax Member

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    I've got an STC-1000, probably about 50 dollars all up by the time I bought myself an enclosure, some extension leads to mangle and whatever else.

    I'm using an old beer fridge that doubles as a backup standalone fridge if we're having a party, also triples as a storage area for all my bottles until I get around to drinking them.

    Excuse the terrible photos, but this is all I've got at the moment
    https://www.dropbox.com/s/ufpopzb0ir3l80k/IMG_20121220_151932.jpg
    https://www.dropbox.com/s/15o5j5a71p2sp8q/IMG_20121220_152006.jpg

    Water was in there to help calibrate the STC-1000 with my thermapen.

    The only thing I need to change is removing the door shelves so I've got more room to get things in/out.
     
  9. darken_rahl

    darken_rahl Member

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    yeah the stc-1000 is tops. i used the following as a guide - simplest i could find:

    diagram (i think the heat and cool lines are mixed up on this though): http://www.thehomebrewforum.co.uk/viewtopic.php?f=23&t=17872
    pic: http://www.flickr.com/photos/74933001@N06/6741424473/

    used a jaycar jiffy box thing.

    this is my fridge - [​IMG]
    i sanitized the probe and dropped it in a fermenter - means the fridge only turns on a couple times a day, rather than on/off all the time to keep the air temp constant.

    and if you've got a computer nearby the fridge, get yourself a usb thermometer with http graphs and email/sms alarms!

    http://www.ebay.com.au/itm/PC-Lapto...ing&hash=item53e2815ef6&_uhb=1#ht_2916wt_1298
     
    Last edited: Jan 29, 2013
  10. DavidP2190

    DavidP2190 Member

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    I use some cheap chinese ebay controller which does the trick just fine. You can put the probe into a bottle of water in the fridge as well, instead of the fermenter, could be a bit safer?
     
  11. darken_rahl

    darken_rahl Member

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    i thought the stc-1000 was a cheap chinese controller? $22 delivered on ebay. which one did you get?

    about the safeness of putting the probe in the beer... that's an interesting one. a couple of points:
    1. the bottle of water will change temperature MUCH quicker than the liquid in the fermenter, relative to the size difference
    2. during rigorous fermentation (the first few days), the wort could be a good couple of degrees hotter than your water bottle - yeast=alive=heat.

    BUT, both of those points are probably not much more than nitpicking. do you have an idea of how many times a day your fridge turns on and off? what settings are you using, (temp set, variance allowance) if you don't mind me asking?

    if you sanitize your probe along with your other equipment then i don't see why it should be a problem. although i am trying to think of something slightly better than just tucking the cable under the lip of the gladwrap seal, which might currently be stopping it from having a tight seal
     
  12. DavidP2190

    DavidP2190 Member

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    I can't even find the controller I got on ebay anymore. I hadn't done much research at the time anyway and wasn't aware of the stc-1000, but it was about $20 anyway.
    As for the temperature difference, I put the probe in a full 2 litre bottle which I don't think changes temp too quickly. The guy at the brew shop here actually just suggests a cup of water, I haven't paid too much attention to how often it switches though, but the fridge is still off most of the time when i have it set at 18 degrees.
     
  13. darken_rahl

    darken_rahl Member

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    that's pretty great then!

    yeah after writing my post i did start thinking about the advantages of the other way. with the probe in the wort, the fridge turns on and off less often, but by that token, it must also be on for longer, meaning that the water surface temp could get quite low. haven't had the yeast die yet, though!

    i'm thinking of getting/making a thermowell, largely so i can reliably sit the probe somewhere near the edge of the fermenter
     
  14. aXis

    aXis Member

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    A tight seal is not required, the carbon dioxide forms a heavy blanket over the top of the wort and keeps pushing oxygen out of the fermenter as more CO2 evolves. You really just need to stop drafts from disturbing it.

    Personally I tape a piece of foam sheet maybe 5cm x 5cm to the side of my fermenter to form a pocket/pouch, and then slip the temperature probe in there. That way it measures fermenter skin temp instead of air temp, and it seems to do a pretty good job.
     
  15. darken_rahl

    darken_rahl Member

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    Ah. I hadn't thought of it in such a logical way. Thanks
     
  16. OP
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    Embercide

    Embercide Member

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    So its perfectly fine to drop the temp probe into the liquid? :thumbup:
    I've got the STC currently running my chest freezer with the probe taped to the side of the fermenter and a chunk of styrofoam over the top to try and insulate from the air but it still turns on every 20mins or so.

    I've got it sent for a temp of 12.2C with a variation of 0.5
    It gets to 12.7 before it turns on, turns off at 12.2 and continues to drop until it gets to approx 11.5.. I'm guessing i haven't insulated the probe enough ?
     
  17. mmBax

    mmBax Member

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    Prove should be fine to drop in as long as its sanitised.

    Use softer foam? It'd give you a better seal.
     
  18. benjagan91

    benjagan91 Member

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    Having sex can make a nice man out the meanest!
     

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