So like many of you I have been looking for a simple, cheap method of fermentation control. I didn't want to look for a mini fridge with a temp controller as I already have a kegerator in the kitchen and a chest freezer in my bedroom closet that I use for cold crashing and cold conditioning kegs.
I found a couple of DIY water fermentation chillers here on HBT like this one: http://www.homebrewtalk.com/f51/water-fermentation-chiller-81501/ but it wasn't quite what I was looking for, although I certainly took some ideas from it.
My basic setup is to use my 10 gallon mash tun as the cold water chamber. I put frozen water bottles into the cold water chamber. I put my SS 3/8" immersion wort chiller into the cold water chamber. I put my bucket fermenter into a large rope handle tub that I insulated with 1.5" rigid foam on the bottom and 2 layers of reflectix insulation around the side. The raw end of my wort chiller tubing is shoved onto a tiny ebay submersible pump that sits on the bottom of the rope handle tub. The other end of my wort chiller tubing (with the female hose thread fitting) is clamped so that its near the top of the water level of the rope handle tub. The pump is plugged into my STC-1000 temp controller, with the waterproof temp probe located up against the outside of the fermenter in the rope handle tub. When the temp controller calls for cooling water is pumped from the bottom of the rope handle tub, through the cold wort chiller and back into the tub.
The best part of this setup for me was the simplicity and cost. I already had the mash tun and the wort chiller, and the only other things I had to buy were:
- STC-1000 temp controller off ebay for around $25 shipped. There are several threads on how to build this such as: http://www.homebrewtalk.com/f51/stc-1000-ebay-temperature-controller-build-330427/ I also had to buy a "project box" from Radio Shack for $9 plus a power cord and outlet for another $10 or so.
- Tiny aquarium pump from ebay: http://www.ebay.com/itm/US-Plug-AC-110V-3W-Submersible-Water-Pump-Aquarium-Fountain-Pond-micro-mini-/160802880572?pt=LH_DefaultDomain_0&hash=item257099 3c3c for $6.50 shipped.
- Rope handle tub for $12 or so.
So basically everything for under $70.
The pump outlet has a tiny removable stub that fits the 3/8" ID tubing perfectly. I used plumbers glue to permanently fix the stub in place. I was afraid such a tiny pump wouldn't be able to push through the 25' of chiller and 25' of tubing, but it works great. It's definitely a slow flow, but that work out perfect to maintain the temp without overshooting it. I have to force water through the tubing to fill it before I hook it up because it doesn't have the power to push all the air out by itself.
I've been using this setup for a couple of months, and it works fantastic! I change out the water bottles in the morning before work and at night before bed. I feel that a liquid to liquid heat exchange is far more efficient and effective than a liquid to air exchange (like a fermentation fridge). Anyway, I hope this helps someone else out there make better beer. Brew strong!!
Here are some pics of the setup: