Goodbye Swamp Cooler, Hello Fermentation Chamber

[lashack]

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.

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).

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!

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

 

[lashack]

Final results

 

[Transamguy77]

Nice job!

 

[hfagner]

Final results
View attachment 678167

Hello Brother! Excellent job.

 

[3 Dawg Night]

Final results

That looks fantastic! Do you think there's room in there with your carboy for a blowoff jar (e.g., 1 gal jug)?

 

[lashack]

That looks fantastic! Do you think there's room in there with your carboy for a blowoff jar (e.g., 1 gal jug)?

Yeah I think so! The collar is barely needed so all the extra room the collar offers is spare for a 1 gallon jug. I can fit my 1000 ml erlenmeyer flask with plenty of extra room.

 

[lashack]

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).

 

[Travis H]

Picked up the fridge today. Got the rest of the stuff on order and should be here Friday. Looks like a weekend project to me.

thank you for the info and photos on this build. I am thinking of not building the collar at this moment and see how it goes.

 

[lashack]

Picked up the fridge today. Got the rest of the stuff on order and should be here Friday. Looks like a weekend project to me.

thank you for the info and photos on this build. I am thinking of not building the collar at this moment and see how it goes.

Awesome. If your fermentor fits without a collar then no-collar is necessary. Although the collar does add some extra room for things like blow-off tube jugs.

 

[3 Dawg Night]

I am thinking of not building the collar at this moment and see how it goes.

How are you planning to get the cables out without the collar? Are you going to drill through the side of the fridge itself, or will you just go through the door/seal?

What do you use for a fermenter?

 

[Travis H]

How are you planning to get the cables out without the collar? Are you going to drill through the side of the fridge itself, or will you just go through the door/seal?

What do you use for a fermenter?

I was just going to run the cables through the door. Should still stay sealed good enough.

I use 6.5 gallon buckets. I mostly do 3-4 gallon runs only.

 

[3 Dawg Night]

I was just going to run the cables through the door. Should still stay sealed good enough.

Let us know how that works!

 

[Cougar281]

How is that heater working? I had tried some plug-in heater I saw at Home Depot, but it was just way too much heat. My current solution in my converted upright freezer is a 75w incandescent light bulb wrapped in aluminum foil with a 120mm computer fan blowing over it to circulate the radiated heat. I wouldn't mind switching to some form of actual heater, but I don't want to over-do the heat.

 

[lashack]

How is that heater working? I had tried some plug-in heater I saw at Home Depot, but it was just way too much heat. My current solution in my converted upright freezer is a 75w incandescent light bulb wrapped in aluminum foil with a 120mm computer fan blowing over it to circulate the radiated heat. I wouldn't mind switching to some form of actual heater, but I don't want to over-do the heat.

I decided to use this heater from others who suggested it on the forums. I have not had to "use" the heater as of yet with an actual batch of beer. If this fermentation chamber is inside and not exposed to freezing cold garages or basements, then the heater really is not needed. So, I cannot vouch for how the heater is working with an actual batch of beer in near-freezing temperatures with chamber outside exposed to colder weather. It does put off some heat but is fairly low wattage compared to other heaters!

 

[Travis H]

How is that heater working? I had tried some plug-in heater I saw at Home Depot, but it was just way too much heat. My current solution in my converted upright freezer is a 75w incandescent light bulb wrapped in aluminum foil with a 120mm computer fan blowing over it to circulate the radiated heat. I wouldn't mind switching to some form of actual heater, but I don't want to over-do the heat.

I live in Southern California, I am not sure that I will need the heater, if anything maybe very little in winter because my brewing stuff is setup in my garage.

 

[Cougar281]

I decided to use this heater from others who suggested it on the forums. I have not had to "use" the heater as of yet with an actual batch of beer. If this fermentation chamber is inside and not exposed to freezing cold garages or basements, then the heater really is not needed. So, I cannot vouch for how the heater is working with an actual batch of beer in near-freezing temperatures with chamber outside exposed to colder weather. It does put off some heat but is fairly low wattage compared to other heaters!

Fair enough. I looked back and found that the heater I had tried was 350W, so I may give the one you used a whirl when the need arises (My fermetation chamber is in my unheated garage, so in winter it's needed, but generally not now). At 150W less, it's very possible it'll be more suited to the task and not over-heat the chamber.

 

[Travis H]

Got mine setup today with out the heater in the mix or the fan right now. Just have the fridge plugged into the inkbird. I set the temp to 65. For some reason the inside temp will get to about 67 and the fridge will kick in and it will drop down to 62

 

[lashack]

Got mine setup today with out the heater in the mix or the fan right now. Just have the fridge plugged into the inkbird. I set the temp to 65. For some reason the inside temp will get to about 67 and the fridge will kick in and it will drop down to 62

Try and drop the temperature probe inside a glass of water or tape the probe to the side of your fermentor using athletic tape. If the probe is just sitting in ambient air, you may get mixed temperature readings.

Another not, you'll also need to adjust the temperature difference threshold that tells the Inkbird to actually turn on. For my setup, I have the unit turn on when the temperature rises 1 degree F above the selected temperature. It will then cool until it hits the selected temperature.

Example:
- The unit is set to keep the temperature at 65 F.
- If the "water" or "wort" inside the unit raises to 66 F, then the unit will turn on to cool.
- The unit will cool until the liquid drops to 65 F. At that point, the unit will turn off.

 

[Ayzala]

Hi, Great build!
I see in one of the pics, there appears to be a door switch. Is there a light in the fridge you had to remove (or permanently connect/break the wires of the switch)? I wouldn't want the light on all the time.
Thanks,

 

[lashack]

Hi, Great build!
I see in one of the pics, there appears to be a door switch. Is there a light in the fridge you had to remove (or permanently connect/break the wires of the switch)? I wouldn't want the light on all the time.
Thanks,

I just removed the light cover which gave me access to the light bulb. I removed the light bulb, placed the light cover back on. No more lights now!

 

[3 Dawg Night]

I ordered a mini fridge from Lowe's yesterday, and it should be available for pickup in a few days. If grown up me could go back in time and tell little kid me how excited I'd be about a mini fridge . . .

I'm wondering about the hole that allows the wires to pass through the collar. Do you feel like there's a lot of thermal transfer through that hole? I'm considering squirting in some expanding spray foam insulation to fill the hole. That's a semi-permanent fix, so if my temperature probe, fan, or heater ever need to be replaced, I'll have to scrape it out of the hole. That's probably not a big deal, though.

Is it even worth the effort, though?

 

[lashack]

I ordered a mini fridge from Lowe's yesterday, and it should be available for pickup in a few days. If grown up me could go back in time and tell little kid me how excited I'd be about a mini fridge . . .

I'm wondering about the hole that allows the wires to pass through the collar. Do you feel like there's a lot of thermal transfer through that hole? I'm considering squirting in some expanding spray foam insulation to fill the hole. That's a semi-permanent fix, so if my temperature probe, fan, or heater ever need to be replaced, I'll have to scrape it out of the hole. That's probably not a big deal, though.

Is it even worth the effort, though?

I was so excited about my fridge, I picked it up 10 minutes before they closed instead of waiting the next day It was also raining.

You are not going to lose any thermal transfer through the hole, it's more work and something that is not the slightest issue. Been using the above setup for 3 different brews, including cash crash temps to 70s and thermal transfer has not been an issue what-so-ever.

Good luck!

 

[bleme]

I live in Southern California, I am not sure that I will need the heater, if anything maybe very little in winter because my brewing stuff is setup in my garage.

I use a seedling heater from Amazon when I am using Kveik or Saison yeast.

 

[3 Dawg Night]

Goodbye swamp cooler! I put together my fermentation chamber over the weekend. I still need to clean up the cables (hole and clips), and I'm awaiting the magnets for the door (so I'm just taping the door shut for now), but everything appears to be working beautifully! What you see here is Belgian Pale Ale that had been in my swamp cooler for six days. I've moved it to my chamber to finish out conditioning for another two weeks. The real test comes in a couple of weeks when I ferment my next batch of American Amber Ale!

 

[lashack]

Goodbye swamp cooler! I put together my fermentation chamber over the weekend. I still need to clean up the cables (hole and clips), and I'm awaiting the magnets for the door (so I'm just taping the door shut for now), but everything appears to be working beautifully! What you see here is Belgian Pale Ale that had been in my swamp cooler for six days. I've moved it to my chamber to finish out conditioning for another two weeks. The real test comes in a couple of weeks when I ferment my next batch of American Amber Ale!

Bravo! This looks incredible! Mine is working fantastically and yours will work the same. Good job!

 

[3 Dawg Night]

Bravo! This looks incredible! Mine is working fantastically and yours will work the same. Good job!

Thanks! I used Danish oil on the collar, because I already had it on hand. I may try to stain it darker at some point, although that's purely cosmetic.

How tightly do you control your temperature? I have the controller set to start cooling at 68 degF (my desired temperature) and shut off at 67 degF. As best as I can tell, the fridge is running every 30-45 minutes for 5-10 minutes.

I haven't installed the heater yet, because here in Alabama, it won't be needed until probably November, even in my garage.

 

[lashack]

Thanks! I used Danish oil on the collar, because I already had it on hand. I may try to stain it darker at some point, although that's purely cosmetic.

How tightly do you control your temperature? I have the controller set to start cooling at 68 degF (my desired temperature) and shut off at 67 degF. As best as I can tell, the fridge is running every 30-45 minutes for 5-10 minutes.

I haven't installed the heater yet, because here in Alabama, it won't be needed until probably November, even in my garage.

I have the cool difference set to 1° F difference. Meaning if it rises 1° F above set temperature, the unit will cut on and cool until set temperature is hit, then cut off. This holds temp pretty tight.

I have also started using a thermowell dip tube rather than the “tape probe to the side of carboy” method. This, from what I’ve read, should give the most accurate reading. Although, the tape to the side method works really well too. Some links are below.

For 6.5 gallon glass carboy
Thermowell - 15" Long w/Hood for... https://www.amazon.com/dp/B074D9DQ6X?ref=ppx_pop_mob_ap_share

For 7.5 gallon Anvil SS fermenter
Homebrew 1/4in Stainless Steel... https://www.amazon.com/dp/B0763SFLLX?ref=ppx_pop_mob_ap_share

I haven’t had to utilize the heater as of yet for the same reasons, plus it’s inside and rarely drops enough to need it.

That being said, my heat difference is set to 2.5° F. Meaning if the wort/beer drops 2.5° F under set temperature, the heater will come on.

 

[DarrellQ]

Goodbye swamp cooler! I put together my fermentation chamber over the weekend. I still need to clean up the cables (hole and clips), and I'm awaiting the magnets for the door (so I'm just taping the door shut for now), but everything appears to be working beautifully! What you see here is Belgian Pale Ale that had been in my swamp cooler for six days. I've moved it to my chamber to finish out conditioning for another two weeks. The real test comes in a couple of weeks when I ferment my next batch of American Amber Ale!

View attachment 683983

Are you just closing the door on the wires? If so, does this affect temperature control?

 

[3 Dawg Night]

Are you just closing the door on the wires? If so, does this affect temperature control?

I was in this picture, because I hadn't bought a hole saw yet. I made it to Lowe's a day or two later, and now the wires pass through a 1-in hole in the left side of the collar.

 

[DarrellQ]

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 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.
View attachment 678149 View attachment 678148

View attachment 678150
View attachment 678151

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).
View attachment 678152
View attachment 678153
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!

View attachment 678154

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

 

[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.
View attachment 678149 View attachment 678148

View attachment 678150
View attachment 678151

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).
View attachment 678152
View attachment 678153
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!

View attachment 678154

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:

Search Results for 12x12 metal sheet at The Home Depot

Search Results for 12x12 metal sheet at The Home Depot

www.homedepot.com

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!