Draft System Access Control

I set up a 2 tap draft system at a hackerspace that has its own homebrew club. We have a full size fridge, and an air cooled insulated supply and return line to the bar's draft tower. There's enough room to expand to 4 taps. Unfortunately, we're victims of our own success. Anything we brew and put on tap gets guzzled in short order, and we'd like to ration how much gets put out for free public consumption.

We're also a bunch of electronics geeks that like to over-engineer anything we can get our hands on. The idea: Use a Raspberry Pi to control access to the draft system, with a display to show what beers are on tap, and what taps are operational vs. what taps are off limits. Then, have some kind of electrically actuated valves to lock each of the beverage lines.

I'm using 1/4" beverage hose. Has anyone done anything like this? My two concerns:

1. I have heard that a lot of these kinds of valves have small orifices and will cause the beer to foam in the line.

2. The valves themselves will be in the refridgerator. I've seen 24V normally closed solenoid valves, but these take a lot of power. For events, we may want all taps open, and if they're all energized, the solenoids will put out a lot of heat into the fridge. I'm instead thinking about something that has a motor or servo actuator, where opening or closing it takes electricity but leaving it in the open or closed position doesn't.

Any help would be greatly appreciated.

Sounds like you are looking for something like the Kegbot.

You can add sensors to calculate how much has left each keg, as well as a RFID reader with solenoids so you can control access.

I got rid of my keezer last year when I moved but I am considering this for the next one...

Instead of putting the valves on the beer line why not put them on the co2 lines to the kegs

Thegreatestgray said:

Instead of putting the valves on the beer line why not put them on the co2 lines to the kegs

Click to expand...

There will still be enough pressure on the keg to dispense beer and if someone does that and uses up the CO2 in the keg, the beer will go flat until it comes back on.

I did this while in school with my first kegerator, and you can make it work, but the solenoid valves are a pain to get foam-free. I ditched the valves, but the flow meters are nice to have.