Minifridge Fermentation Chamber

Built this last year and it turned out quite well. It was definitely a project that took way longer than expected but I am completely satisfied with it. I bought a minifridge off of CL for $30 and gutted the compressor and heat exchangers. I rewired it to be controlled by a Love TSS2. I wanted something that could hold 2 carboys and was portable so I can move it out of the spare bedroom/office for when we have guests and need to blow up the aerobed. I used caster wheels to be able to move it around. The 2 on the back don't rotate. The 2 on the front rotate and lock so it doesn't move around unintentionally. I wanted it to look like nice. I also wanted to be able to easily lift carboys out of it and place them on top for racking. Here we go.













Initial Fit Test.







I wanted to use hidden hinges, which was a bit of a challenge. I couldn't find hinges that will work with doors this thick. These will work with doors up to an inch or so, can't remember the exact max. So you have to route out the frame to get it the rest of the way there.







Bought the heavy duty 180lbs drawer rails from Lowes. With 1 carboy I can pull the drawer out all the way without it tipping forward. With 2 carboys it will tip forward if I pull it out all the way, but I can pull it out half way move one carboy then pull it out the rest of the way to get to the one in the back. I used expanding foam to mount the insulation and fill all of the gaps.







Ran a temp test to make sure it could hold temps before sealing up the last piece of insulation. Got it down to 32F and held it there overnight. Used a wireless devkit we had lying around at work that has a thermistor on it to monitor the temps inside the chamber and was able to log it on my laptop. Here is a demo of the CEO using the Cypress FirstTouch devkit to monitor temps in his winery.



I wrapped the outside with 1/4" oak veneer plywood.



Everything is sanded, trim pieces are installed and its ready for stain.



2 coats of gel stain and 2 coats of polyurethane



3 months of working here and there on nights and weekends with the little free time I get and it is all done.



I wanted to use internal door catches, but I couldn't find any that had enough strength to hold the door shut while compressing the weather strip enough to get a good seal. I settled on these latches. I could have probably found something better looking, but at this point I really wanted to be done with this project.















It also holds 6 of the old returnable cases. I have a fan installed in front of the heat exchanger to move air over it. The fan is wired in parallel with the compressor so it is only on when the compressor is on.

Wow, very impressive!! That thing looks straight up professional.

Very well done. This gives me some ideas!

Amazing! Well documented. What are the max and minimum temps this system can reach?

TommyKy said:

Amazing! Well documented. What are the max and minimum temps this system can reach?

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I only have it setup to cool as I don't need to heat at all in San Diego. I can get it down to 32F, haven't tried going any lower than that as I will never need to.

That is awesome..... I need to make me one

What was the size/model of the original fridge vs the size of the new chamber....

medvitz said:

That is awesome..... I need to make me one

What was the size/model of the original fridge vs the size of the new chamber....

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The original unit was a Haier BC-111. It was 32" tall, 21" wide and I believe 20" deep. If you subtract out the wall thickness and inside shelf where the compressor is this puts it at ~4.5CF.

The new box is 41" tall, 21" wide and 32" deep. Again, subtracting the wall thickness and inside shelf this puts at 9.5CF.

Love your design and drawer shelf. Any idea for the total cost?

Really Nice Work.

great work..... was it tricky to rip the fridge apart???

Wow, that is impressive, thanks for the great documentation! Do you think it would be possible to do that same thing, only with one of the long sides as the door so as to avoid having the sliding tray?

I've been wanting to do this same setup for the past month or so with a fridge and wood I have here. Unless I do it at 3:00a.m I don't see that happening anytime soon with this heat. Great job! Does the coil ever get any ice build up on it? Do you have any pictures or information on how you wired up the fan?

Erroneous said:

Love your design and drawer shelf. Any idea for the total cost?

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I don't really. It took about 3 months to build and I bought things in different stages and never added it all up.

CBelli said:

great work..... was it tricky to rip the fridge apart???

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It really wasn't too bad. Ripping the metal skin off of the outside was the hardest part. After that I just had to cut away the insulation and plastic as you can see in the second picture.

amazing! you wouldnt happen to have a blueprint of this?

machinelf said:

Wow, that is impressive, thanks for the great documentation! Do you think it would be possible to do that same thing, only with one of the long sides as the door so as to avoid having the sliding tray?

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Probably. I don't see why not. Obviously you would need more room to open the door all the way. Before I decided on going with the drawer I was thinking about having a second door on the top that only went back half way but I didn't think that I could get a good seal between the 2 doors.

StainlessBrewing said:

I've been wanting to do this same setup for the past month or so with a fridge and wood I have here. Unless I do it at 3:00a.m I don't see that happening anytime soon with this heat. Great job! Does the coil ever get any ice build up on it? Do you have any pictures or information on how you wired up the fan?

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No ice build up but I do get some condensation on it. Since I have the fan running while the compressor is on the heat exchanger never gets below freezing. The fan is wired in parallel to the compressor so it is tied to the same neutral that goes to the compressor and the temp controller. The switch leg output from the temp controller goes to both the fan and compressor.

This isn't a great picture but hopefully you can see what's going on.







the wire on the right plugs into the wall the one on the left goes inside where the tube for the heat exchanger goes in. The ground from the wall goes to the plate that the compressor is mounted on. The compressor ground and the ground going into the chamber are also mounted to the plate. The line (black) from the wall goes straight into the inside to the temp controller. The neutral splits and goes to the compressor and into the chamber. The switch leg from the output of the temp controller comes back outside the box with the yellow wire which connects to the other terminal on the compressor.

sorefingers23 said:

amazing! you wouldnt happen to have a blueprint of this?

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These aren't pretty by any means and my handwriting sucks. you will most likely have to tweak some dimensions in the back to accommodate the compressor and heat exchangers you would end up using. The grid spacing is to 1 inch scale. I thought about sketching this up in Visio but I spend about 10-12 hrs a day at work in front of a computer so I went with the notebook on the couch while watching TV. Hopefully this is of some use to someone out there.

crane said:

These aren't pretty by any means and my handwriting sucks. you will most likely have to tweak some dimensions in the back to accommodate the compressor and heat exchangers you would end up using. The grid spacing is to 1 inch scale. I thought about sketching this up in Visio but I spend about 10-12 hrs a day at work in front of a computer so I went with the notebook on the couch while watching TV. Hopefully this is of some use to someone out there.

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Thanks

Thanks Crane!

So after the hot humid summer I ran into mildew issues from condensation dripping off of the heat exchanger. I unplugged it and took the door off to dry it out. The hinges I used have a quick release so I can pop the door off really easy. I let it dry out and then cleaned all of the mildew stains with bleach water. I bought a 4x8 sheet of 1/16th inch poly board. I attached the poly board with liquid nails and then sealed the seams with silicone caulking. I had to take the drawer apart and cut it down to account for the extra thickness of the poly board on the walls. Here is the result.




I am also going to keep a thing of damp rid in there from now on to soak up any moisture. I am cursing myself for throwing away the drip tray that was in the original mini fridge. I may try to rig something up if I can find a plastic tray of some sort that is the correct dimensions.

Condensation....ahh....hmmm.

sablesurfer said:

Condensation....ahh....hmmm.

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Condensation has only been a problem when:

1. I had the chamber in the garage for a few months and it was the hottest part of the summer getting above 100F everyday out there.
2. I drop temps into the 30s over a few weeks for lagering.

So it really comes down to the fact that the larger the difference between ambient temp and chamber temp the more condensation will be produced.

However, I now use damp rid in there all the time and I have no condensation issues but do have to dump it out and refill it every couple of months. I saw another guy on here using some reusable evadry devices that you plug into an electrical outlet to dry them out after they saturate. I haven't gotten around to buying any yet but I would like to go that route.

Those are listed on home brew finds, looked at them a couple times.

First on on the page as of 2/12/14.
http://www.homebrewfinds.com/p/top-finds.html

I have a condensation problem with my fermentation chamber too.. I have an Eva dry inside, but the chill plate is still producing water droplets.

Btaz said:

I have a condensation problem with my fermentation chamber too.. I have an Eva dry inside, but the chill plate is still producing water droplets.

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It's been unusually humid here in San Diego lately and I have had condensation on the cold plate as well but with the damp rid in there I am no longer getting puddles on water on the floor and don't have any mildew issues. As long as the condensation is just on the cold plate you should be fine from my experience at least.

Old thread, I know, but I was wondering how the chamber has held up. I am thinking of a similar setup.

chessking said:

Old thread, I know, but I was wondering how the chamber has held up. I am thinking of a similar setup.

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It's still going strong without any issues after 4 years of use. I've had a month or 2 here and there each year where it sits unused, but the majority of the time it's had fermenting beer in it. It can still get into the low 30s for lagering, although I don't use it for lagering as much as I did in the past now that I have another larger fridge in the garage for cold conditioning/lagering.

Crane, great build! I have been thinking of something just like this and am definitely going to use your drawings and steal you design. Thanks for the pictures and detailed documentation!!!

Mountainsax said:

Crane, great build! I have been thinking of something just like this and am definitely going to use your drawings and steal you design. Thanks for the pictures and detailed documentation!!!

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Glad you find this helpful. Let me know how it turns out