The Weber Fermentation Chamber

TimWeber · 01-25-2010, 11:16 PM

After this summer's heat my wife and I realized that we couldn't brew consistently or well if we didn't have better temperature control during fermentation. We have one fermentation fridge but I only holds one carboy and we were brewing once a week. I decided it was time to build a walk in cooler!

Now I really can't take credit for coming up with this. I absolutely have to thank John Beere for the inspiration as well as a few others on this site. I'll add acknowledgments as I find the threads :-)

My Requirements:

It would be large, large enough to hold a lot of fermenters.

It would have multiple temperature zones.

I needed to be able to take it apart and move it if need be.

I wanted to be able to load fermenters easily.

I wanted to be able to carbonate kegs in it, and store bottled beer.

Lots of fermenters meant a chest freezer would not work. I had an extra 5000 BTU window air conditioner lying around, so I opted to use that instead of a dorm fridge. Before going into the details of the build I'll just give you a picture of the final product.

The chamber on the left is for lagering, carbonating and storage and is held at 35F. The chamber on the right is for ale fermentation and held at 68F. It's been in operation for a few months now, and holding strong. The lager chamber can hold 15x 6.5 gallon carboys and the ale chamber can hold 5x 6.5 gallon carboys and two conditioning cases. Next, I'll post how I made it.

TimWeber · 01-25-2010, 11:16 PM

I started off by constructing the four sides of the chamber. I decided to go with 3x2s to try and reduce weight a bit. The walls were constructed similar to house with a cross beam on the bottom and top. I used mold resistant paneling for the outside.

On the left side I made a hole for the AC unit. This was where I made my first mistake. I made it a bit too short and a bit too long. I hadn't yet decide if I wanted to use the window fillers that came with it.

I decided to make the step up in the front for two reasons. The first was for structural rigidity. The second was the thought that since cold air sinks, maybe less cold would fall out of the chamber every time I opened the door.

I bolted each side together so that I could disassemble the unit if I wanted to move it. I placed window striping along each side at the joint, outside of the bolts to seal the sides.

TimWeber · 01-25-2010, 11:17 PM

Making the floor of the chamber. This is it upside down. I used 2" foam insulation and tons of GreatStuff.

The door has a compression fit. I put weather striping all along the outside. To latch it shut I actually have to lean against it.

TimWeber · 01-25-2010, 11:17 PM

The top is built in 3 pieces. I did this to reduce the weight I had to lift, and also it provides more support to the front of the chamber, as the door puts some torque on that front wall. The side pieces are bolted to the top.

The AC unit needed to be modified a bit. I put a panel of fans on the front to blow across the evaporator to try and de-ice it.

I had to disable to the PCB on the AC unit in order to force it to cool below 65. I'll follow up with a schematic as soon as I find it.

I plugged the AC unit into a Ranco controller. Hey and ELECTRICITY WILL KILL YOU! DON'T DO WHAT I DID. IF YOU TOUCH A CAPACITOR THAT HAS NOT BEEN DISCHARGED IT CAN KILL YOU.

What that capacitor. That'll knock you on your butt if it doesn't kill you. I let it discharge for 24 hours then grounded it and checked it with a DVM just in case. I am very afraid of electricity.

TimWeber · 01-25-2010, 11:18 PM

I then started building the ale chamber

I drilled a hole in the bottom of the lager chamber.

I stuck a drier vent in the hole.

Then I stuck an AC fan on the inside to blow cold air out.

I put a drier hose at the top of the ale chamber.

Building the floor to the ale chamber

This was the best way I found to mount the probe for the lager chamber. I drilled a hole in the top of a whitelabs yeast vial, filled it with water and poked the thermistor from the Ranco down through the top.

And again the final chamber. I may add taps to this at some point. The lager chamber is at 35F and the ale at 68. I went back and use 1/8" foam to cover the entire inside and the floor. Turns out wood is a good conductor of heat. I will probably add more insulation come summertime. Right now it turns on for about 10 minutes every 3 hours.

TimWeber · 01-25-2010, 11:18 PM

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TimWeber · 01-25-2010, 11:19 PM

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TimWeber · 01-25-2010, 11:20 PM

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TimWeber · 01-25-2010, 11:20 PM

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TimWeber · 01-25-2010, 11:21 PM

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