Introduction: Convert a Chest Freezer to Kegerator or Fermenter for $20

Picture of Convert a Chest Freezer to Kegerator or Fermenter for $20

So there's a couple other instructables already about converting a chest freezer to a kegerator (aka keezer), but most of them use the expensive plug and play temperature controllers.  If you're willing to get your hands a little dirty, cheap controllers to hardwire in can be found on eBay for ~$20.  Not only do you get a nice digital readout with the current temperature and the ability to set to specific temperatures, you also have the option of adding a heat source as well to turn the freezer into a temperature controlled fermenter.

Temperature controller:
I purchased mine for $20 (Link removed due to seller jacking price up $100).  eBay links don't last forever, but you can search for "digital temperature controller 110V."  Many of them are designed to run on 220V, so make sure you get the proper voltage controller (110V in the US).  This particular one allows for many customized settings include compressor delay, which is important as rapid on/off cycling can kill the compressor.

Tools needed:
Dremel/rotary tool or jigsaw
Wire cutters
Multimeter (recommended)

Misc parts:
Wire nut
Electrical tape
Extra power cord

Step 1: Preparing the Freezer

Picture of Preparing the Freezer

Foreword:  You need to be very careful about cutting through the walls of the freezer as most of the walls contain the cooling element.  If you puncture a cooling element, all the coolant will leak out and you'll be left with a fancy box.  In my freezer, the was an area in the bottom right side that contained the compressor, enough room to install the controller, and a thin wall obviously devoid of any cooling parts.

Measure the size hole you need to cut and trace it out on the wall.  Double check you're not drilling through the thick part.  Drill a hole in each corner and cut between them with either a dremel tool or jigsaw.  If using a jigsaw, make sure the blade won't poke through far enough to hit and of the compressor lines.  Make sure the controller will fit in the hole you cut.

An alternative to mounting the controller on the freeser is to use a plastic junction box and put the controller in the middle of the existing power cord.  A blank faceplate provides a suitable surface to mount the controller.  The finished results may not be as neat, but it gets the job done.

Step 2: Wiring in the Controller

Picture of Wiring in the Controller

The first thing is to cut the plug end from the existing cable (unless you're using the junction box, then cut somewhere in between).  It's important to note which line is the hot and which is the neutral.  The ground is usually smaller and pretty easy to identify.  After cutting the cable, the wiring schematic shows the hot going to the thermostat which is in the panel I pulled out.  I looked for the wire coming in from the power supply and after disconnecting it from thermostat, tested for continuity with the multimeter.  Since the end connected to the thermostat is the hot, you should get no resistance on the other end of that same wire.  Mark it with electrical tape or black marker.

The way the temperature controller work is by cutting on and off the flow from the hot to either a heating or cooling element.  Both circuits are normally open.  When the temperature gets too hot, it will close the circuit and allow electricity to flow to the cooling element (the freezer).  If I was using the freezer as a fermenter I might also have a heating element like a small ceramic heater or dehydrator connected that would be turned on when the temperature dropped too much.

To wire it up, the incoming (black cord in my case) hot and neutral get connected to the appropriate posts.  Here the hot went to post 5 and the neutral to post 6, as shown on the diagram.  The hot also needs to be connected to the post to switching portion before reaching the heating/cooling elements.  Because post 1 and 5 both need to be connected to the incoming hot, you need to either pigtail a split in or do what I did an jumper a second short wire between the two.  Next you need to connect the outgoing post shown going to the cooling element to the line that goes to the freezer (white cord here).  Although the diagram shown this to be post 2, I found this to be a misprint and that post 3 actually is for the cooling element.  Initially the freezer came on when the temperature was too low, which could have had disastrous implications if I didn't catch the mistake.  Post 7 and 8 get connected to the included temperature probe, it doesn't matter which leg connects to which post.  The neutral going to the freezer should get attached to post 6 along with the neutral coming from the outlet. The grounds don't actually connect to the controller and should be joined directly to each other.

Before sealing everything up, plug in the freezer to make sure it is all working as intended.  To set the temperature, press set, use the up/down arrows to select the temp, then press reset.  Test both when the probe it too hot or too cold.  You can hold it against an ice cube if you need to cool it down.

Step 3: Finishing Up

Picture of Finishing Up

Run the probe up the back of the freezer and snake it under the lid.  Duct taping it to the freezer is a good way to keep the cables managed.  Fit the controller through the hole and use the orange clips to hold it against the wall.  They can be a little tricky to get on, but keep at it.  My controller operates in Celsius, so fridge temp is 4 degrees.  If yours is in Fahrenheit you probably want to set it to 39 or so.  This particular freezer was tall enough to kit kegs and carboys right off the bat, but I'll be installing a wooden collar and faucets as detailed in other instructables soon.  In the mean time a picnic tap will get the job done.  Good luck and happy brewing!


DconBlueZ (author)2011-12-15

Cool 'structable, I caught the link before the seller got greedy (or woke up, whichever may actually apply) so I have my $20 controller in hand, now searching Craigslist for freezers. I think I'll mount it in a box on top though for easier access. BTW your brew setup looks identical to mine.

I'm thinking about putting the whole shebang in the basement under the kitchen and running a tap up through the wall to the kitchen sink's vegetable sprayer cutout, but the tap hose would have to be about 12' long, not sure if that would cause problems.

MrBippers (author)DconBlueZ2011-12-15

The problem with that setup is that the beer in the lines between the sink and freezer will get warm. You would have to add something to keep the lines cold. There's a nice post about one guys solution on homebrewtalk in the form of a DIY line chiller that pumps cool water to the sink and back.

DconBlueZ (author)MrBippers2011-12-15

Hmmmm...not sure I'd want to have a pump running continuously just to keep a hose cool...maybe I could rig a check valve so as to let the line drain back into the keg...gotta think about it. Thanks

MAWSR (author)DconBlueZ2014-11-25

run the hose upstairs inside a 2"pvc pipe filled with expandable insulation.that should keep it pretty cool.

kevinlc77 (author)MAWSR2017-01-26

dont forget you're going to want to clean the line every once in a while, so a permanent line is going to be more maintenance. as well as requring quite a bit of co2 pressure to pump liquid to a upstairs location. so you're going to be spending $ on a larger co2 tank as getting it filled more often.. just build a nice keezer and walk downstairs to get a beer..

CharlieH47 (author)2016-08-22

Just curious, how many years are people getting from their kegerator?
I used the external plug and play device and have mine ready to go. I
plan to use this as a fridge and beer cooler, but only if it's the most
economical way to do do so.

Wild-Bill (author)2016-08-09

I did mine many years ago during my Lagering phase. The freezer eventually failed. since then I have been using an all fridge where no electronics are needed. Oh, I keep my hops in an actual freezer. I never leave my kegs attached to the C02, as I find it totally unnecessary as I never put more that 16 litres into a 19 litre keg (I do 30+l batches). I really enjoyed your instructable. Prost, skál, sláinte, lloniannau, cheers

rpeterika made it! (author)2016-04-11

After frying one set of electronics, and then almost frying another (both my fault, not the instructable's), I recommend springing for the extra $40 bucks for an expensive plug-and-play controller. DIY car audio did not prepare me for appliance re-wiring.

rogersba17 (author)2015-08-17

I like this! I made a chest freezer kegorator using a thermostat from a from an old fridge but after about a year that broke now I need to do this! But also replace all my hoses and pretty much everything else... Oh well, loved the instructable and look forward to fixing mine!

Wolfster001 (author)2015-06-23

I found one for under $17.00...

Also installing 2 computer fans, one on each side one blowing down the other up will circulate the are and eliminate any warm zones...

thaefathan (author)2015-06-07

My 7.1 cu ft chest freezer ( draws 12.1 amps on start up. The STC 1000 is only supposed to carry 10amps, does any one worry about this much?

Freezers (author)2015-02-11

That's cool, but wow long did it take to do everything?

BrianK8 (author)2015-02-10

February 2015: When I first did this in the UK many years ago, it cost me a fortune. Skeptical at how cheap these are, I followed your advice and searched ebay for a "digital temperature controller 110V.", I found a few to choose from and was able to pick one up for under $15 including shipping from china. I am not sure if it is an updated model of the one pictured in article but the controller is a single relay type that can be programed to either heat or cool to a set temperature that you choose, so in short it’s ideal for a number of projects requiring heating or cooling. Rather than cutting holes into a Freezer to mount the controller I would personally recommend wiring the controller to switch an electrical socket on and off and simply plug the freezer into this socket. The temperature probe should be ok if left hanging over the wall inside the freezer with the door closed. THANK’S for an inspiring article.

cdigiovanni1 (author)2011-12-08

I've seen this done on many homebrew sites to control fermenting temps and for kegerators. I use a Johnson Controller that sits between the power plug and wall. The only problem is that the temps lead to condensation and mold. Between every beer I ferment I have to clean it. I am not sure how you would control this in a kegerator setup without cleaning it out every two weeks.

rickets19 (author)cdigiovanni12014-04-17

Get an Eva-Dry wireless dehumidifier like this:

MrBippers (author)cdigiovanni12011-12-08

If you're having problem with mold and condensation, try putting some desiccant in there. DampRid is one option.  This will absorb the extra moisture which should cut down the mold too.

eclectic99 (author)2013-11-28

Back when i made my keezer from the Johnson controller, i noticed the placement of the thermocouple inside the chest was important. The bottom was cold, the top was hotter. I put a spare 12volt 5 inch dia. computer cooling fan i had in the chest and the entire inside of the chest had a uniform temperature. I run this all the time because i keep bottles as well as corny keg in all the spare spaces. See attached photo.

valhallasmine (author)2013-04-22

Thanks for the nice plan! Can this type of rig facilitate brewing lagers up around the 70F, then descending temp control in about 2 deg/day increments?

theZeigs (author)2013-03-13

Whereabouts did you set the controller to not come on and off rapidly to avoid burning out the compressor? Thanks.

cscottjones87 (author)2012-08-20

On there controller's output, I noticed it says 220V. My compressor says it operates on 110/120V and I noticed the one in the picture does to. How is that okay?

MrBippers (author)cscottjones872012-08-21

Think of the output rating as up to. It operates as an on off switch so if you are feeding 110V in, you will only get 110V out when it is 'on.' The input voltage is important because that needs to run the electronics in the circuit and is designed to work at a particular voltage.

Capt Chumbucket (author)2011-12-11

I have a high regard to keg beer. To the tune of a keg about every 2 to 3 weeks. My question is, without the assistance of a Incredibile Hulk type of partner, how does one load a FULL keg into this contraption. My True brand keg-o-rater is starting to get louder each week and I can predict a call from Dr. Korvorcian in the near future. This would be a suitable replacement if I could load it without the use of steriods. Any suggestions?

evvo (author)Capt Chumbucket2012-01-15

Engine Hoist? (also fun for playing Superman with your gf!)

1 eye hook, a cheap block & tackle/ total cost ~$12.00 US

The kegs I use are 5 gallons so they're not that heavy. It'd be a beast to get a full 1/2 into this on a regular basis. I have bad enough memories of dragging them up the stairs of my college apartment. If 1/2 kegs are your regular thing, just get a cheap full size fridge and put the hookups in that--no temperature controller needed. You could probably use an engine hoist but a regular fridge would be much cheaper.

Beergnome (author)MrBippers2011-12-12

having spent the better part of the last 12 years as a professional Keg wrestler, I would say the more or less safest and easiest way to lift a keg by hand is to first grasp the keg handle with your favored hand, tip the keg 45degrees, and grasp the bottom ring with your other hand.
after this, pull the whole thing up to rest in a horizontal position across your belly while arching your back slightly back.

this puts the weight of the over a wider area and resting on your pelvis instead of your spine, and arching the back shifts the center of gravity to be going straight down your legs.You should now be able to walk around in this fashion as relatively comfortable as walking around with 150 pounds hanging off your belly is going to be.

you should now have theb2 thing high enough off the ground to bring it to the lip of the Freezer chest and you should be able to gently control putting the keg in by revesing the method you used to pick it up.

one of these days I'm going to have to make a 'ible detailing this method

I may have "one-uped-you". For the past twenty years I have been carrying around about 3/4 of that 150 lbs.. As of late, gravity has taken it's toll and it has been hanging somewhat below the buckle. I fear my arms may not be long enough to circumnavigate the keg as you discribed. Thanks for your help though.

Thanks for the input. I think I'll go with the small reefer after the present True kicks the preverbal bucket.

northerntx (author)2011-12-11

The #2 terminal should be used for the Compressor/Evap fan, sense it has a time delay built in to keep the compressor safe from repeated start ups.
This delay can range from 1 minute to 5 minutes.

The #3 should be used for the heating elements, That is if you have a defrost setting. This terminal will have the voltage when #2 does not, and it will become inactive when you have the voltage to #2.

MrBippers (author)northerntx2011-12-11

Right, that's the way the directions say it should work. However in actuality with mine it was the other way around. #3 is controlling the cooling with the proper programmable compressor delay (3 min by default) and activates when the temp is over. I think it was a most likely a translation issue. Follow the instructions for your controller first, but make sure it's working properly once installed.

MichaelAtOz (author)2011-12-11

Note: The ebay seller seems to be profiteering from the link above. Over $100 for a $20 item? Search wider and you will find cheaper.

MrBippers (author)MichaelAtOz2011-12-11

I just pulled the direct link, thanks for pointing it out. Again, just make sure you get one that specifies 110V input, as there are also ones that operate on 220V.

JakeBlanton (author)2011-12-11

When I built my kegerator earlier this year, I used the Johnson Controls A419 unit. It was around $70-75, IIRC. I wish I had known about these ones from China back then. I could have saved $50.

pblasman (author)2011-12-11

Following your eBay link, is a temperature controller that lists for $119.88. However, if you search eBay for 120 V temperature controller, you will find several that are around the $20 price range.

Great idea, I've been thinking of doing something like this myself.

ccrome (author)pblasman2011-12-11

Ooh, nasty. It looks like they increased their price from $19.88 to $119.88. They must have discovered that somebody linked to it. That's really nasty. I almost didn't notice the price, $119.88 looked about right, until I saw the extra $100.

Deceptive for sure.

kklepper (author)2011-12-08


This is the best keg conversion write up I have seen to date. You mentioned that you could add a heat source to turn the freezer into a temperature controlled fermenter. I am looking to make a controlled fermenter. Can you comment on how you would add a heating source? I would also like the ability to use the freezer for carbonating kegs as well so I would need the ability to bring the temperature back down.

Thanks for the great post.

Beekeeper (author)kklepper2011-12-11

I did something similar to this using an old apartment size fridge which had already had the compressor removed. I use it for raising bread and making yogurt, but the principle is the same. I used a copper bulb type thermostat with a 60 watt bulb as my heater and it works very nicely. I put a fuse in the circuit for good measure.

MrBippers (author)kklepper2011-12-08

With this style controller it's pretty simple, the controller actually powers the heating circuit when the temperature gets too low even if no heat source is connected. To add a heat source you would connect the hot wire going to the heating element to the proper post. The instructions say that would be post 3, but again with mine 2/3 were flip flopped so it'd be post 2 here. You then tie the neutral in with the others. Three wires on a post might get a little crowded, so you could use a wire nut to tie all three neutrals together along with a forth wire which runs from the wire nut to the controller. If the heat source has a ground, connect it with the others and you're all set. Chest freezers are so well insulated they make great fermenters and I'll probably pick up another to do that once I find one that will comfortably hold at least three carboys.

mikeasaurus (author)2011-12-07


About This Instructable




Bio: I'm a PhD candidate in Pharmaceutical Sciences living the dream with my wife, two dogs, and a basement that overfloweth with homebrew.
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