I am currently lagering a Baltic Porter. I hooked CO2 to it while it was in the fridge just to do two things at one time. I went out to the garage last night to enjoy a cigar and checked on it - no pressure. I had a leak. I had done a leak test using star-san spray on the posts and center opening. But not a thorough test after connecting the tank. And now with no CO2 to pressurize the system I may not know what the problem was, but in thinking about it, I came to wonder about the application of keg lube.
How often should I lubricate the rubber O rings? I have never done it, but I only have one or two brews on each of my 3 corny kegs.