Finished Product
Several months ago I heard some interviews with expert homebrewers advocating for better control of beer fermentation temperatures. The yeast used to ferment beer (producing alcohol and carbonation from sugars), is most effective in a relatively small temperature range. Above that range you may get off-flavors, while below it the beer may not fully ferment. The temperature in my apartments fluctuates quite widely, especially in the winter. We have a programmable thermostat in the apartment to keep it between 60 and 67 degrees, depending on time of day. Most yeasts prefer the 68-72 degree range, disliking temperatures down at 60 degrees. I needed some type of heater to warm my beer up and keep it at a constant temperature. As an added bonus, this project might be able to do double duty as a temperature controller for a sous vide water bath, but that’s another post. You can see the Temperature Controller in the photo to the right. A display shows current temperature of the sensor and what the set point is. The set point is adjusted with a potentiometer knob on the bottom of the box (not visible because of the lighting, but to the left of where the wires enter on the bottom). The “0″ on the bottom right of the display indicates that the relay is currently switched off. When the temperature drops enough, the relay switches on and the display shows a “1″ in that position. You can find links to the source code, schematic, board layout file, and parts list at the bottom of the post. Since there is no good licensing scheme for open sourcing hardware designs, if you use my board layout please at least give me credit. (more…)