Fermentation Chiller

This is a gadget that I ran across one day on the net. It's basically a big cooler to control the temperature of fermentation. It has a thermostat inside that controls a small fan that recirculates air across some ice jugs inside the chiller. In a 70 F room, it can easily hold a temperature of 45-50 F. All you have to do is change out the ice jugs when they melt every couple of days (which is another reason I need the freezer compartment on my beer fridge).

The design for this ingenious invention came from Ken Schwartz. I printed the plans straight off the web and followed them exactly. Construction was fairly easy and I finished in one evening. You can see and print the plans by clicking here as well as get a detailed description of its operation. Ken used to have Fermentation Chiller kits available, but I think they have since gone out of business. It's more fun to build it yourself anyway.

There are several reasons why this invention is better than having a refrigerator with a temperature controller:

1. For most ales, an air temperature of 60 - 65 F is needed to keep an ale fermenting at 68 F depending on the stage of fermentation. This is a lousy temperature to serve beer (I don't care much for "Real Ale"). This means you can't have fermenting beer and kegged beer for serving in the same fridge (unless you like warm beer).

2. It's portable. When empty, the chiller only weighs 5 lbs or so which makes it easy to move around or store out of the way when you're not using it.

3. It uses less electricity. The only power requirement is running a 12 VDC fan and freezing the ice jugs in a freezer.

It took me while to realize it, but controlling fermentation temperature has a profound effect on the finished beer. Can you make decent beer at room temperature? Sure. Can you make great beer at room temperature? Not likely. If you live in a warm climate, trying to keep ales at 68 F or lower can be a real challenge. There are simple methods like covering the carboy with a wet T-shirt, or submerging the carboy in a tub of water with some ice. To me, these were not very elegant and the Fermentation Chiller design was just too cool (sorry, no pun intended) for me to pass up.

It is amazing how well the Fermentation Chiller works. I can keep a furiously fermenting ale at 68 F with no problem, or I can ferment a lager at 55 F even with an ambient room temperature of 75 F. I keep an extra set of ice jugs in my freezer and just swap them out when the ones in the chiller melt.

As of 8-23-02, I have two of these chillers in operation. They are completely separate so I can set each one independently. I did this mostly because with only one, I couldn't brew more often than every two weeks and still control the temperature throughout fermentation. This made it hard to brew for parties or whatever. Now, I can brew as often as I like.

I have noticed a real improvement in my beer since I have been using the chiller. Some of the typical homebrew off flavors like the funky fruity esters and higher alcohols have gone away. I highly recommend this piece of equipment.

Free Advice About Ice Jugs

1. Gallon milk jugs are NOT recommended. They are prone to rupture over repeated freezing/thawing cycles. Unfortunately, you won't know about the rupture until the ice melts - bad scene (been there, done that, more than once).

2. You can put the milk jugs into gallon sized Zip-Lock bags to catch the leakage. You won't be able to zip the bag closed and it is a VERY tight fit (do this while frozen), but this has worked for me. Cheap insurance if you are dead set on using the cheap jugs.

3. I have switched over to using some plastic jugs I found at US Plastics. They are industrial strength plastic gallon jugs with screw caps. They stand up to the repeated freezing/thawing much better and can take significantly more abuse than the flimsy milk jugs. Because of the thicker plastic, they don't seem to cool quite as well as the milk jugs as measured by the internal air temp (about 2 - 3 F higher), however, the ice seems to last a bit longer. These are Part# 66152 at www.usplastic.com, about $1.50 each.