Goodbye Swamp Cooler, Hello Fermentation Chamber

[3 Dawg Night]

Fantastic job! I'm building this soon. A couple quick questions. Is it safe to drill into the left (when looking inside) side of the refrigerator to mount the fan as the schematics I looked at show the cooling coils running through the left side? I may not need the framing for my size fermentor, do you recommend any other ways to get wires inside? Thanks in advance.

You could try just closing the door on the wires. That's what I did for the first day or two before my hole saw was delivered. I don't think you'll lose a ton of thermal efficiency at the temperatures we're dealing with. It might deform your door seal over time, though.

 

[garzlok]

Fantastic job! I'm building this soon. A couple quick questions. Is it safe to drill into the left (when looking inside) side of the refrigerator to mount the fan as the schematics I looked at show the cooling coils running through the left side? I may not need the framing for my size fermentor, do you recommend any other ways to get wires inside? Thanks in advance.

I saw the picture of the fan attached to the inner wall and thought to myself that was a pretty gutsy decision. If it was me, I don’t think I would have had the courage. I would have used Very High Bond (VHB) double sided tape, and figured a way to mount it.

For the wires (if you’re not putting a collar on), as mentioned, just close the door on them. If you want a cleaner look, you’ll have to figure out a way to go through the fridge safely.

 

[TsunamiMike]

I surf this forum religiously when embarking on a new adventure or project. Thanks to everyone who contributes and I hope to help others with this post.

I have been on and off brewing beer for about 5-6 years now and have been using a swamp cooler to try and control temperatures. This works for the most part, but constant monitoring and inability to brew lagers drew my interest in dialing in my fermentation game. Due to my small home, I decided to build a DIY mini-fridge fermentation chamber that would hold one 6.5 gallon glass carboy with airlock. I decided to purchase a mini-fridge brand new rather than dealing with Craigslist and hoping to find something that would fit my specifications.

Some other considerations made were:
- Not having to cut, scrape, and bend components inside the fridge. Minimum destruction as possible.
- I want the ability to ferment at ale and lager temps, as well as cold-crash.
- Try to set up something fairly simple.

Fridge and Collar
I bought the Frigidaire 4.4-cu ft Mini Fridge from Lowes for $179.99. The door came off with no problem, just a few screws. I knew I would need a collar, so I used a 2x6 to place around the fridge. Then I used some Gorilla Glue to glue the collar on the fridge with some ratchet straps to apply pressure until the glue was dried. Liquid Nails would have probably worked better because it doesn't set near as fast, but does take more time to dry. I then used some DAP Kwik Seal caulk for a nice seal around the inside space of the fridge and collar. No extra insulation was added and with a preliminary test, temperatures held just fine. I am able to get the fridge down to 34F/1C no problem. I also used some linseed oil and wood finisher to seal the wood so things like beer/water wouldn't funk up the wood collar over time.
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Temperature Controlling Components
As far as the components that help regulate temperature, I used the following:
- Simple fan to circulate the air. This fan runs all the time.
- Low wattage heater to provide heat.
- BTC201 Temperature control unit. Plug both the heater and fridge into this unit, which then is plugged into the wall.

To mount the fan, I drilled from the inside of the fridge with a 1/8 drill bit through the plastic, enough to get the mounting screws for the fan to have a tight fit. It mounts nicely like this. Then used a 1-inch wood drill bit to drill out a hole where the wires will run (the heater and fan wire out, and the temperature probe line in). These really came in handy for cable management too. Mounted the BTC201 directly to the fridge on top (had no issue drilling into the top of the fridge).
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Final Touches
The door does not stay shut unless you use some sort of latch or some way to use the magnetic structure built into the door. I decided to use 3 rare earth magnets burrowed into the collar. This helped keep the door sealed to the collar. I will post the final result in the comment section. I'll also try and keep this thread updated when I brew a batch and test out the chamber!

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Thanks again everyone and here are some YouTube videos where some of the inspiration for this build came from.
- Link 1
- Link 2
- Link 3
- Link 4

So, without the “collar” on the mini fridge would the carboy fit on the bottom with the door closed?

 

[3 Dawg Night]

So, without the “collar” on the mini fridge would the carboy fit on the bottom with the door closed?

Looking at my picture above: man, it would be close. You could try it, and then add the collar if you need it. Building the collar is really not that difficult. Wood glue and screws at the joints, then some JB Weld or similar adhesive to glue it to the face of the fridge.

 

[lashack]

So, without the “collar” on the mini fridge would the carboy fit on the bottom with the door closed?

That's a negative. The glass carboy is about 1-2 inches too big in diameter from fitting with the door closed, hence the collar. Your other option is to cut out some of the door that others on the forum have done. Basically cutting out the plastic and insulation in the door.

Looking at my picture above: man, it would be close. You could try it, and then add the collar if you need it. Building the collar is really not that difficult. Wood glue and screws at the joints, then some JB Weld or similar adhesive to glue it to the face of the fridge.

Just like what @3 Dawg Night said, try without a collar. If it doesn't fit you can ethier cut part of the door out or use a collar.

 

[Will_the-new-brewer]

If you are interested in the door staying shut without latches, you can buy 1' metal squares at Home Depot. I trimmed it down into "equal" strips and glued it to the wood (made it look as nice as I could). The magnet inside the door liner sealed against the metal wonderfully...and no latches.

I forget which one I bought, but these are what I am referring to:
https://www.homedepot.com/s/12x12%20metal%20sheet?NCNI-5
I took a magnet with me to make sure it was what I wanted.

 

[DarrellQ]

I use Duck Tape to hold the door shut, works great!

 

[Bago-0]

What is the internal width of the fridge? I looking to build something but ferment in a 1/4 barrel sankey keg and the width seems to be the problem finding a fridge. The keg is 17" diameter.

 

[lashack]

What is the internal width of the fridge? I looking to build something but ferment in a 1/4 barrel sankey keg and the width seems to be the problem finding a fridge. The keg is 17" diameter.

The internal width of the fridge is 16 inches. Unfortunatly, I do not think a 17" diameter keg will fit!

 

[jmika003]

PS I recently bought the Anvil 7 Gallon Stainless Steel fermentor and it also fits in the chamber! You have to turn it to the side because of the handles, but it still fits with plenty of room (including airlock).

Is this setup working well with the Anvil fermenter? I'm thinking of buying one and pairing it with a similar chamber build, so looking for input. Chamber looks awesome by the way!

 

[jddevinn]

Great documentation.

If you plan on cold crashing look up positive pressure to prevent oxidation.

 

[lashack]

Is this setup working well with the Anvil fermenter? I'm thinking of buying one and pairing it with a similar chamber build, so looking for input. Chamber looks awesome by the way!

Yes, the 7.5-gallon Anvil fermentor fits with the airlock in this chamber. It's been a great setup for me! Good luck.

 

[lashack]

Also, I wanted to mention that I recently switched out the original heater with a Germination Heating Pad wrapped around the fermentation chamber on the side held on with some velcro straps.

Here is the germination heating pad I am using: https://www.amazon.com/dp/B085FC2CD6/ref=cm_sw_em_r_mt_dp_5iuRFbT820Z3A?_encoding=UTF8&psc=1

Here is the velcro strap I am using: https://www.amazon.com/Chattanooga-...=velcro+ice+pack+straps&qid=1605190403&sr=8-5

I haven't used this setup (or the small heater in the original build) yet in freezing temperatures. For example, if the fermentation chamber was outside in a garage during the winter months. But I have used the germination heating pad for Kombucha with this same setup indoors and it keeps the fermentation nice and warm (around 79-80F). Just wanted to share the updates.

 

[jmika003]

Great! Thanks for the updates!

 

[jmika003]

Yes, the 7.5-gallon Anvil fermentor fits with the airlock in this chamber. It's been a great setup for me! Good luck.

Would you by chance be able to take a picture of the Anvil bucket in the fridge? Just trying to get an idea of what the fit is like.

Cheers!