Limiting oxygen exposure once yeast has been pitched is a critical part of producing good beer. There are a lot of ways to avoid oxygen throughout the brewing process, but I’ve always struggled with purging kegs. A number of different methods are used for this – you can blow CO2 through your keg, as one example. Or you can fill a keg with water, and then displace that with CO2. But I have issues with these methods – they waste CO2. So I’ve designed a basic 3D printed keg purging system. This system kills two birds with one stone – it serves as a blow-off, and allows you to purge your kegs with CO2 captured from your fermentation.<\/p>\n\n\n\n
The concept behind this system is quite simple. A blow-off tube directs the CO2 of your ferment into a wide-mouth mason jar. The jar collects any material that gets blown off, while an outlet on the jar collects the clean CO2. This CO2 is directed to the liquid-out port of the keg, thus “filling” the keg from the bottom with CO2. An airlock attached to the gas-in port allows gas to vent while keeping room-air out. Making all of this possible is four 3D printed parts, which can be produced for less than a dollar.<\/p>\n\n\n\n
The embedded video, below, shows the system and goes over how to put it together. This companion article gives additional assembly details and described a bit more of the underlying concept. Now, without further ado, the video:<\/p>\n\n\n\n