Dutch’s Cadillac Fermentation Chamber Build

Seems its ferm chamber frenzy here on HBT so thought I’d jump on the bandwagon. Here’s my build …

I started with a 17-cubic upright, frost-free freezer that I got off craigslist for $100 (Kenmore, Model # 253.21721103). The unit was built in 2002 and is in awesome condition. I decided to go with a freezer for the added insulation in the walls and doors. Chose a frost-free model to avoid having to bend shelves.



I removed the wire shelves and installed a custom fit shelf built from 1” x 2” poplar (I chose wood as it seems to be relatively glass friendly). I spaced the slats 0.75” and blind screwed for a clean look. The center support can be repositioned or removed completely depending on the situation.

As for shelf height, I opted for 25.5” (to the bottom support) to allow room for cornys on the bottom (with QDs attached, just in case). On top, I can fit two six-gallon carboys.



The chamber will live in the garage, so I needed a way to move it around. I built a platform out of 2” x 4” lumber fitted with 3” locking casters from Harbor Freight http://www.harborfreight.com/3-inch-swivel-caster-with-lock-95356.html (rated at ~250 pounds per caster).

For temperature control, I settled on the Johnson Controls A419 (ordered from Pex Supply http://www.pexsupply.com/Johnson-Co...age-Digital-Temperature-Control-120-240v-SPDT for $54.95). I prefer the Johnson over the Ranco because it offers an anti-short circuit delay (should be a little better on the compressor). I wired it myself using a 15 foot, 14-gauge extension cord (thanks to redbenn https://www.homebrewtalk.com/f11/how-wire-johnson-controls-a419-167453/ for the wiring diagram).
I mounted the controller on the door and fed the sensor through a small hole on the side of the door. The sensor probe sits in a small glass vial (VOA vial) half filled with water.





Overall, I’m really happy with the build. Best of all, over the last week, its pulled just over one KWH.





In the future, I’m planning on removing the door shelving and replacing with an acrylic panel. This will allow me to increase the depth of the shelf and fit three carboys on the shelf and four to five cornys down below. I may also section off the bottom area with foam insulation to create separate lagering and ale fermenting chambers. To do this, I would need to redirect the cold air output to the lagering chamber and install a separate temperature controller and fan to pull cold air out the lagering chamber into the ale chamber. We’ll see ...

Looks nice and clean work!

Its getting warmer and warmer, need to keep our little yeasties happy!!

That looks great. I really like the shelf design. Not sure if I just missed it but did you secure the fridge to the dolly or just let gravity do the job?

I know a lot of people do the probe in water thing. Do you control the actual temperature of the beer by looking at the carboys and changing your controller accordingly? I attach my prove directly to the carboy but that obviously gets tricky when you have a bunch in there.

Krrazy said:

That looks great. I really like the shelf design. Not sure if I just missed it but did you secure the fridge to the dolly or just let gravity do the job?

Click to expand...

Right now, gravity is doing the job. I'm still working on a plan to secure the freezer to the dolly. May use straps or bolts through the bottom.

Krrazy said:

I know a lot of people do the probe in water thing. Do you control the actual temperature of the beer by looking at the carboys and changing your controller accordingly? I attach my prove directly to the carboy but that obviously gets tricky when you have a bunch in there.

Click to expand...

I'm still tweaking the temperature control; trying to dial in a configuration that works best. I have LCD temperature strips on the carboys, which I assume are fairly accurate. I'd love to be able to measure the internal temps, but don't have a thermowell.

Right now, the temp controller is set to 64 degrees (as I'm juggling a Kolsch, Pale, and a Wheat and trying to hit the medium). My Wheat is actively fermenting and is reading out at 64 degrees (on the LCD strip), the other two are conditioning and are reading out at 60-62 degrees.

I also have two temperature probes in the freezer to measure air temps: one on the floor and one on the uppermost door shelf. I'm seeing the air temperature fluctuate a bit. I'm not too worried, though, as long as the fermenters stay in the proper range.

I came across this thread while searching online for the manual for this freezer, but I also asked posted a thread on the beginners forum this morning about setting the freezer up with the same temp controller https://www.homebrewtalk.com/f39/need-advice-regarding-running-temperature-controller-into-freezer-258441/. A few weeks later, have you changed the way you set this up regarding the temperature controller? Several people have responded that they don't like the probe in the water approach, preferring the attaching the probe to the carboy. Have you had trouble keeping the temp you desired?

walrusbt, I'm still using the probe in water. I find it maintains a consistent temperature range, but about four degrees lower than my setpoint. I have a kolsch going right now and am aiming for 60 degrees. My setpoint is 62 degrees with a differential of 1 degree and I see the chamber fluctuate from 58 to 62 degrees. I believe the swing is do to the probe in water plus the mass of the freezer walls, etc. This really doesn't bother me as I'm hitting the proper temp according to the LCD strip on my fermenter.

The probe-in-water vs probe-in-air debate rages on.

At work, we run an environmental laboratory. They use dozens of thermometers to measure/confirm the temperatures in fridges, freezers, and ovens. Not a single probe is left open to the air -- thermometers in the fridges and freezers are submersed in glycol; in the ovens, they're placed in a jars full of sand. Apparently this is the only approved method of measuring air temps.

That being said, while this is the best method for measuring temps, I'm still unsure if it's the best way to control temps.

I'm leaving the probe in water not so much to measure true air temps, but to minimize compressor cycling.

BTW, I checked out your post in the beginners forum, looking good -- you're going to LOVE that freezer.

Looks great!

I've just gotten started on the idea of using a freezer as a fermentation chamber. I had planned to use a chest freezer, but now that I see your setup, I'm starting to wonder if this isn't a better route.

Any suggestions or things you wish you had done differently? Have you found a good way to keep the temperature at a constant level?

I think I understand your theory for placing the thermometer in water, but i think you might need a slight change.
I have not brewed anything yet, I'm still purchasing equipment, and the A419 is next.
If my understanding is correct you want the temperature of the beer to change slowly and uniformly. Ideally the beer would not change temperature but due to chemical traits of fermentation this is not possible, and some people start fermentation at a lower temperature than when it finishes as their brewing practice.
By placing the thermometer in water it ensures the thermometer does not get any unreliable temperatures, i.e. air movement, opening of the freezer/fridge etc.
The assumption in this situation is the temperature throughout the entire freezer/fridge is uniform. I believe this to be inaccurate, the fermentation process is what is going to increase the temperature of the freezer, not the door, or air movement. So to fulfill your theory, I believe you would need to place the fermentation containers (carboys in this example) in water, not the thermometer.
I am thinking of placing the thermometer on the top of the most active fermentation container in the fridge/freezer...? We'll see.