Fermentation Chamber - Converting an old freezer into a temperature controlled fermentation chamber
I've been wanting to do this for a long time, but really didn't have the time until recently. I had an old, working freezer that wasn't in use, and my conical fermenter fit inside of it perfectly.
In the past, my brewing was limited to ales that I could ferment inside my house in carboys...but last year I got a 13 gallon conical fermenter, and moving it full of beer from the garage to the house was a major challenge. We had an upright freezer that wasn't in use, and I thought this would be perfect for controlling the temperature of fermentation. The project only took a few hours and turned out far better than I anticipated. I'm fermenting my first lager with it now, and it seems to be going exactly as I had hoped.
Project Materials:
- One working Freezer
- STC1000 or equivalent temperature controller
- 2 Halogen lights (incandescent would work as well here - I liked the price and form factor of the halogen lights I used. LED is NOT a good choice here - this light needs to generate heat).
- 15 foot, 14 gauge or higher extension cord
- crimp connectors for 14 gauge wire
- Plastic retrofit box with duplex receptacle
- Velcro with adhesive
- Clear silicone adhesive
Goals:
- Make as few modifications to the freezer as possible - specifically, I didn't want to cut the electrical cord to the freezer. I did that for my keezer and the wiring got messy.
- Make sure that I don't drill through any of the coils...that makes the freezer useless...
The project:
The freezer I used had a sheet metal shield over the refrigeration coils. I removed it knowing that I wanted to drill a hole for the temperature sensor and power to the halogen lamps I was going to use to heat the freezer (for ales in the winter). When I removed the shield it was pretty clear what I needed to do.
You can see in the upper right hand part of the picture that there was a plastic panel where the wiring came through. I measured the outside to figure out how thick the wall was behind the plastic cut-out and seeing that is was ~1" I was confident that it was safe to drill a hole. I drilled a 1/2" hole through plastic, styrofoam and sheet metal on the back of the freezer. Just enough to thread the power cable and sensor wire through.
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The next challenge was wiring. The STC1000 is pretty simple, but I did have to think about how to make it work. I designated the top receptacle for the heating circuit and the bottom for the cooling circuit. In the wiring diagram below I used a non-conventional color - the wire shown as red should in fact be white (neutral), but a white wire is hard to see on a white background, so ignore convention in this diagram. I'm using the relay circuits on the STC1000 to switch the hot side.
One note - in order to separate the receptacles so they can be turned on independently, I had to cut the brass line on the hot side so that the STC1000 could turn on heat and cool independently. On the neutral side, I left the connection intact since it simplified the wiring for me.
One note - in order to separate the receptacles so they can be turned on independently, I had to cut the brass line on the hot side so that the STC1000 could turn on heat and cool independently. On the neutral side, I left the connection intact since it simplified the wiring for me.
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That is really the bulk of the project. Everything else was just finish work.
- I did put a piece of wood on the bottom of the freezer to protect it from getting scratched by the legs of the fermenter.
- I used velcro to stick the halogen light on the side of the freezer.
- I used velcro to put the J-Box on the side of the freezer.
- I used velcro to put the STC1000 on top of the freezer next to the J-Box to minimize wiring.
- I put the conical fermenter in and screwed the plastic fitting with the temperature probe into the thermowell.
- I used an empty tennis ball can filled with water for my airlock.
- I did put a piece of wood on the bottom of the freezer to protect it from getting scratched by the legs of the fermenter.
- I used velcro to stick the halogen light on the side of the freezer.
- I used velcro to put the J-Box on the side of the freezer.
- I used velcro to put the STC1000 on top of the freezer next to the J-Box to minimize wiring.
- I put the conical fermenter in and screwed the plastic fitting with the temperature probe into the thermowell.
- I used an empty tennis ball can filled with water for my airlock.
It is true that the STC1000 only measures temperature in Celsius. For me that was a minor consideration, I understand the conversion, and the price more than justified the minor inconvenience for me. All roads lead to better beer! I have high expectations for my first lager.