Fermentation Control Upgrade

The Ranco two-stage controller holding the Belgian Tripel fermentation at 69 F

The fermentation chamber has done a fantastic job of holding the proper fermentation temperatures for the past few brews, however I realized that sooner or later, I would need a controller and a method of heating the ferment if I hoped to get the process of fermentation under the control I have hoped for.

The AC unit so far has been great at holding fermentation temperatures steady. Depending on where the beer is in the process of fermentation, I would simply let the analog thermostat of the AC unit cool the chamber to a few degrees below my targeted fermentation temperature. The cooling of the AC would equilibrate with the heat produced by the yeast during fermentation, and result in a constant temperature. This process worked well, but necessitated frequent checking of the beer's temperature, which could only be viewed by opening up the chamber and looking at the temperature strip on the side of the carboy (in the process, releasing the cold air from the chamber). 

The AC unit was also made more inefficient by the fact that without a controller, there was no way of having the unit turn on only when needed. The unit was constantly running and was more often than not simply circulating air inside the chamber with the fan inside the unit. Rarely would the AC unit kick on to cool the fermentation. It was obvious that much of the time the AC unit was on it was simply wasting energy.

The most significant concern I've had with respect to the fermentation chamber was that as the weather has gotten colder, the need for cooling has decreased while the need for heating has increased. The chamber has been doing a decent job of insulating the beer from these colder temperatures, but I'm sure that soon the heat created by fermentation will not be enough to heat the inside of the chamber.

After doing a bit of searching, I found a great fermentation control system on MoreBeer.com. The controller is a Ranco digital two-stage controller which allows either two cooling units, two heating units, or my current arrangement, one heating and one cooling unit to be turned on and off according to the temperature of the fermentation. I currently have the probe taped to the side of the fermenter and insulated with some cloth, but I think it's registering a slightly lower temperature than the actual fermentation temp. 

Along with the controller purchase, I also bought a thermowell that will solve this issue. The thermowell is a stainless tube just wide enough to hold the temperature probe of the controller. The thermowell will be immersed in the center of the fermenting beer and offer a more accurate temperature reading. The difference between the exterior fermentation temp (as I have been reading it from the fermentation strip on the oustide wall of the carboy since I began brewing) and the internal temp of the fermenting beer will be very small since the volume of fermenting beer is fairly low, but I'm anal and this should offer me the best temperature reading I can get.

The probe (grey cord) measuring ferment temp, the FermWrap (black cords) heating the ferment

The piece of equipment I chose to heat the fermentation is the FermWrap. The wires of the FermWrap split into a grid of coils in a plastic sheet, much like the way in which a window defroster for the back window of a car works. The plastic sheet wraps about 3/4 of the way around the carboy and allows for heating directly to the side of the carboy. So far it appears that it is a quick and efficient method of heating the ferment. The only time I have seen either the AC or FermWrap turn on (other than when I am stepping up temp on the controller) the FermWrap came on for a few minutes to heat the ferment back up one degree and quickly shut off after. Overall I am ecstatic with this particular purchase; I think it is likely the most valuable brewing equipment purchase I have made. It should allow for brewing of any ale style I can think of, and with some tinkering I have planned in the future on the AC unit, it could even allow for me to begin brewing lagers in cooler months. The thought of a Baltic Porter or DoppleBock during the winter has me excited to see if I can achieve lagering temperatures with my new fermentation chamber setup.