My Kega-Fermerator Build

My wife took me down to our LHBS for Valentine's Day and told me I could get what I needed to start brewing my own beer. Little did she know what an obsession this would become!

We live in north Alabama, and temperatures are in the 90s fairly often, which means our house stays around 77F during the day. I tried various methods of cooling the closet where I keep my fermenters, with some success. I bought some foam insulating board and built a small enclosure around my fermenters, along with a 2liter bottle of ice and a computer fan to keep the air circulating. That can get the temperatures down around 70F for 12 hours or so, but that's not quite good enough. So I've been keeping my eyes open for a cheap refrigerator.
(Note: All images with descriptions are in my user gallery.)

I managed to find a decent (read: working) one on Craig's List for $25:


The inside is pretty spacious and should easily fit three fermenters in the bottom portion:

The bottom portion will be the fermerator part of my build. I have plans to eventually experiment with the freezer portion as well. If I can get the temperatures fairly stable up there as well, I'm considering trying to put some kegs up there. I can fit 3gallon kegs upright or 5gallon kegs tilted to one side. Once I get around to that part I'll post pictures of it as well. For now I just have the fermerator in place.

The shelving in the door doesn't really buy me anything at this point and takes up about 4 inches of space that could hold fermenters instead, so it's got to go!


Next to figure out the refrigerator wiring. This one has a thermostat mounted in the back in between two interior illumination lights. The wires you see hanging down should go to a door open switch, which wasn't in the refrigerator when I got it. The connection works though, so I'll put a new switch in later. On the warmest setting the refrigerator stays around 50F, so I had to replace the temperature controller.

 

The refrigerator control panel is pretty simple:

Freezer temperature is controlled by limiting air flow from the freezer into the refrigerator. I'll leave that in place. The only electrical circuits here are the thermostat relay and the humidity control switch. I wanted to keep the humidity control and replace the thermostat with a new temperature controller.

A close up of the control panel:

Purple and pink wire are used by the condensation control switch. Brown and gray go through the thermostat. I disconnected the later two from the relay and tied in two new wires.

Close up of the wiring in the back of the refrigerator:

It wasn't too tough to figure out where each wire went with a volt meter. Green is ground, orange is common, brown is hot. Pink is hot when the condensation control is engaged. Gray is hot when the condenser is powered. I already had wires running to the gray and brown wires, so I also attached one to common and another to ground.

After wiring these up, I replaced the refrigerator control box:

The short blue wire goes to ground. Red is common. One of the long blue wires is hot, while the other goes to the compressor.

Based on this link I decided to put an electrical outlet on the inside of the refrigerator so that I can power a stir plate and/or a heat lamp (should the refrigerator temperature get too low):

The outlet box was mounted to the heat shield used by one of the interior illumination bulbs. The outlet on the right is always powered, while the one of the left is controlled by the new temperature controller:

 

Next I had to mount the new temperature controller. Since I had already removed the door shelving, I decided to remove the insulation as well. I wasn't really comfortable with the insulation being exposed in the same space as my beer wort:

Without the shelving in place the door is really wobbly. I'll deal with this as well as the lack of insulation in a minute.

First, I cut a hole in the door for the temperature controller.

After marking the location for the controller, I drilled a fairly large hole in two opposite corners then used a jig saw to cut out the rectangle.

The interior width of the door was 1.5inches. A 4'x8' sheet of 0.5inch thick foam insulating board was sufficient to cover the door three times:

The two interior layers were a bit oversized, so they cracked a bit when I shoved them in place. However, their larger size helped provide a bit more rigidity to the door. It feels sufficiently solid now. The third layer was done in two pieces, which allowed it fit in place without cracking too much. One lesson learned here: I used "Goop" to glue the layers of insulation together, but that type of glue puts off quite a bit of fumes. They still haven't completely dissipated. I would suggest using something else.

The temperature controller in place:

I used the Love Model TSS2 controller. I wanted the dual stage model so that I can separately control the compressor and the heater outlet mentioned above.

The controller wired in to the rest of the system:


A close-up lets you see how this thing was wired:

One set of red/blue wires is common/hot respectively and has direct electrical connection to the refrigerator plug. The other pair of red/blue (the one closest to the bottom of the photo) controls the electrical outlet (heater) and compressor respectively. Notice that the hot wire (blue from the first pair) goes into the wire nut and splits into three separate connections. One goes to the controller hot (terminal 4). The other two go to the center of the two switch relays (terminals 7 and 10). The compressor is wired to terminal 8 and the heater outlet to terminal 11.

The temperature controller in operation:

 

Cool looking project.

I wonder if it might be a good idea to mount that outlet on the left, a little higher.

 

Now that the wiring is done, I need to make the inside of the refrigerator suitable to hold fermenters. The bottom of the refrigerator is not at all flat, so I had to put in some shelving:


First, I built two supports for the shelf:

There is a lip on the back wall of the refrigerator that can support the back edge of a shelf. The middle support fits down in the lowest point in the refrigerator, which also happens to be the only flat spot on the entire bottom! The front support sits on a sloped surface but was still sufficiently stable.

The supports mounted to the shelving boards:

The shelf is made from two boards rather than one only because I was using scrap wood I had in the garage.

The shelf sitting in the refrigerator:

The one issue I had here was that the shelf could slide around a bit. It was very unlikely to slide out of the refrigerator since one of the supports was sitting at the low point. Also, there are two little plastic tabs sticking out of the sides of the refrigerator that were meant to support the original shelving. Now the serve to keep the new shelf from easily lifting out or moving around too much. I considering gluing the shelf down permanently. However, I've seen enough fermentation disasters that I wanted to be able to clean out the bottom of the refrigerator without too much hassle if the need every arises. But that means I need something else in there to make sure the shelf stays secure.

To that end, I glued a small strip of leftover wood down to the bottom of the refrigerator just in front of where the front shelf support sits:

I used "Gorilla Glue" both for this and to attach the wire conduit to the top of the refrigerator. That stuff works really well and had no trouble gluing both plastic a wood to the painted metal surface on the inside of the refrigerator.

The shelf securely in place:


I decided to include one more addition. My fermenters have spigots on them, and I've occasionally used those to take hydrometer samples. That means that I sometimes get small drips of wort on the shelf where I keep my fermenters. I'd rather not have it soaking into the wood, and I don't want to line the inside of the refrigerator with newspaper like I do my closet. However, I had a sheet of scrap black lexan in the garage as well. I cut out a sheet slightly larger than the wood shelf and slid it in place:

The lexan sheet is not permanently attached, which means I can take it out and clean it off easily if I get any drips (or explosions!) on it.

 

Total cost of the project:
$25 for the refrigerator
$85 for the temperature controller and probe
~$15 for the wiring, electrical outlet, and conduit
$10 for the foam insulation board

If you don't have the wood or plexiglass available, that would probably run another $10 or so. Check the scrap piles at Lowes or Home Depot for bargains.

So all together, I put in about $135.

 

I got the outlet mounted as high as I could. It doesn't extend quite as far in any direction as the interior illumination light shield did. Also, without knowing exactly where the condenser coils were located, I didn't want to screw into the walls of the refrigerator. The heat shield for the illumination lamp worked pretty well. With the plastic conduit attached securely to the top of the refrigerator (Gorilla Glue), the outlet box is in there pretty solidly. It might be worth using an outdoor outlet cover, but this one should be okay.

 

Oh, my perception of the orientation of that pic was messed up. I thought it was a different view than it is. It looked to me like the outlet was mounted all the way down at the bottom of the fridge.

 

Ah, I see what you mean. Yeah, the 5th picture down in post #3 gives you the best view of where everything is.

 

Your Black Lexan pic appears not to have any black lexan...


Also, this is groovy, I have that exact model of fridge in my garage right now.

 

Thanks. Fixed that.

 

I never got around to posting a picture of my fermerator in action. Here it is:


On the left I have AHS Cannonball Stout in the ale pail. On the right is Edwort's Apfelwein in the Better Bottle. The flask on the stir plate is a starter for Pelikan's DC Rasperry Stout that I'll be brewing later on this week.

 

One suggestion I should add is that your wires to your controller should of been longer so that you had a 10" to 12" minimum "U" loop with plastic spiral plastic wrap around your wires. This drop loop takes the flexing vs bending the wires in a short distance causing the copper to eventually break down strand at a time until a total broken wire failure occures. On heaters check out the Hoffman Engineering Company they have Design Air electric heaters. They have a 100 watt that I have that has a small computer fan as well a heating element that is app 3/16" diameter in loops. This element is only 100 watts and just around 200*F not a glowing red element. This small 100 watt unit is 4" x 4" x 4 1/4" cube with a temp control knob with a range of 0*F to 100*F or -20*C to 40*C. A fully enclosed metal box with vent slots all around. They also have a 200 watt unit. I went thru the light bulb thing until a lamp element failure happened in 22*F weather in a patio with broken carboys. I saved this brand new Hoffman unit from the trash at a job site a good save for the next fermenter frig build.