I'm thinking about switching from fermenting (primary and secondary) in glass carboys to using Cornelius kegs. Specifically, I'd ferment a 5.5 gallon batch in a 10 gallon carboy.
My goal is to ferment under pressure -- around 10 or 15 psi. Why? There's some anecdotal evidence that fermenting under pressure reduces ester production which could help with lager fermentation. But mostly, the pressure would a) let me remove yeast and trub after a few days of fermentation, and b) let me transfer the finished, carbonated beer to a serving keg under pressure
How can I regulate the pressure of fermenting beer in a Cornelius keg?
I can image a setup where the gas in line (with the tube removed, perhaps) is connected to a blow-off tube with an in-line pressure regulator. The regulator would need to be adjustable, so I could dial in different pressures for different beers, and at different stages in the fermentation.
I'm not sure if such an in-line regulator exists. I also expect it would need to be resilient to moisture. Fermenting 5.5 gallons in a 10 gallon vessel, there's not much chance that liquid will end up in the blow-off tube, but I want to be prepared for it if it does happen.
Has anyone ever put together a setup like this? Can anyone foresee technical difficulties I haven't thought of?