Mini fridge collar - fermentation chamber

I just finished up adding a collar to a mini fridge I got for free. I could not fit a 6.5 gallon or even a 5 gallon carboy in the fridge before. I didn't want to mess with bending the freezer part or relocating the fridge's thermostat so I decided to just extend the fridge about a foot.

I built a 2X4 frame and added casters and used plywood for the collar. I wedged the fridge onto the frame into some 90 degree brackets to hold it in place, which seems to be working ok so far. I screwed the collar into the frame and then used great stuff to seal the two pieces together. I also added some brackets on top using the original holes where the fridge door was mounted. I then added some polystyrene or whatever its called (R6) and added some wood to the bottom to level the bottom out and protect the polystyrene. I used the original door and hardware, but cut the shelf out and put a piece of 1/4" plywood over the inside. I used magnetic strips that I glued on with Gorilla Glue to create a seal. Finally, I added an analog Johnson temp controller and I now have some Scottish Ale fermenting away!









Do I have the temperature sensor attached correctly? Pretty sure I read just to tape it to the carboy.

I still need to add a bit more spraypaint in spots and cut away some of the excess glue from the magnets, but it's functional the way it is.

Looks nice. I'm getting ready to start a DIY just like this. Does it have any issues holding temps?

jedIPA said:

Looks nice. I'm getting ready to start a DIY just like this. Does it have any issues holding temps?

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Honestly I can't really say yet, my basement is usually about 62-66 degrees and I have the controller set at 62 for this ale so it hardly has cycled on at all. I'll probably brew a bock next so I can really test it then. After I bottle this ale I'll set it down to 40 or so next week too and I'll post an update then.

Looks great. Congrats I can't wait to get some better temp control with my ferments.

very nice, that should work out great for you.

you might want to put some bubble wrap or something over the sensor so it's more in tune with the carboy and less influenced by the ambient air, but it probably isn't that big of a deal.

Thanks for the comments. I'll give the bubble wrap a try next time I think that will work great.

Just an update, haven't used this much until I brewed an Octoberfest last week. The fridge has maintained 50 degrees all week and barely cycles on at all. My basement is about 64 degrees right now, so it's not much of a task, but I'll try lagering when primary fermentation finishes. We'll see how low I can get it without the compressor having to stay on 24/7. I'll post another update in a few weeks.

Holding 35 degrees easily for lagering. I think I'll build another one of these to hold 4 kegs when I get some kegging equipment.

im going to be making one of these bad boys here very soon out of an old fridge from the college days that has been collecting dust. I think Im going to make it a tad bigger so i can fit a 6.5 and a 5 gal carboy that way i can control temps of of beers that are ferm. and ones that are conditioning (assuming the same temp range of course)

Question, you mentioned using a magnetic strip to create a seal for the original mini fridge door to the wooden sleeve. Did you make any use of the original rubber gasket thing a ma bob that is use in every fridge door in America or what that simply scraped along with the rest of the door paneling?

At least in the first pic it kinda looks like he did. I stole his idea a few months ago () and just used a little superglue to glue the insulation back onto the door, then used a couple of these latches except the metal piece was a 90-degree bend so I could screw it into the side of the door.

CircusBoy said:

Question, you mentioned using a magnetic strip to create a seal for the original mini fridge door to the wooden sleeve. Did you make any use of the original rubber gasket thing a ma bob that is use in every fridge door in America or what that simply scraped along with the rest of the door paneling?

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Yes, the original rubber gasket stayed on the door (this gasket is magnetic). The magnetic strip was attached to the edge of the wood so the door would stay shut. It's still working fine to this day, now this is my kegerator.

I'm making one of these myself - thanks for posting this, it is very helpful!
I just bought one of those temperature regulators at my local homebrew store in Grand Rapids, and the guy told me to put the temp sensor in a container of water. I guess people drill a tiny hole in the top of a water bottle and tape it to the fridge, but the water holds the temperature better and prevents the fridge from turning on and off all the time.
At least, that's what I was told.

pbylsma said:

I'm making one of these myself - thanks for posting this, it is very helpful!
I just bought one of those temperature regulators at my local homebrew store in Grand Rapids, and the guy told me to put the temp sensor in a container of water. I guess people drill a tiny hole in the top of a water bottle and tape it to the fridge, but the water holds the temperature better and prevents the fridge from turning on and off all the time.
At least, that's what I was told.

Click to expand...

You should put it on the carboy, but put bubble wrap on the outside of sensor to insulate it from the air. That way it adjusts for the temp of the carboy and not the ambient temp or the temp of a cup of water. Remember that during active fermentation the yeast generate heat so the carboy could be up to 10 degrees warmer than the ambient temp.

Nice. I want to try to accomplish this. My kegerator is a tad too small to fit 2 Cornys or a Slim 1/4.