Lagering in the keg/headspace question

[pig140]

I just switched to lagering in the keg and I have a question. After transferring to the keg, I hooked up the CO2 and purged the keg a few times. Then I disconnected and put it in the fridge at 34 degrees. That was about 8 weeks ago. I just hooked CO2 back up to start carbonating. I noticed I could hear the headspace filling back up with CO2.

I assume the beer absorbed the CO2 I had left in the headspace? So what is left in the headspace - a balance of CO2 between the beer and empty space? Or did I not purge it enough and there be O2 left in there?

 

[oceanic_brew]

If you hadn't pressurized the headspace the shrinkage the wort would endure from cooling could cause suck back of O2 into the headspace (provided there wasn't a decent seal)

It sounds like you only purged with the gas on so you would have a positive pressure.

Did you properly seat the lids with 20PSI or greater?

If so, and if you did apply more pressure to the headspace with co2 then that pressure will dissolve the gas into the beer. You would have to leave the gas on for a while before you would actually reach an equilibrium between dissolved gas in the beer and pressure being applied to headspace/keg.

Just recently got into kegging myself but this makes most sense to me.

 

[kombat]

There's no need to disconnect the gas while lagering, nor is there a need to lager for so long. I treat my lagers like I treat my ales. 2 weeks primary ferment, 1 week diacetyl rest, then into the keg in the fridge, on 12-15 psi of CO2 for 2 more weeks to carb up. If I'm concerned about clarity, I'll pop the lid of the keg on day 2 or 3 (after it's had time to cool down to temperature) and hit it with a little gelatin. After 2 weeks, it's pouring clear, but if you wanted to "lager" it even longer, just refrain from drinking it for a few more weeks. Let it sit there, in the keg, carbing up.

 

[pig140]

I should've said I keg in 1/6 sanke kegs, so no lid. Two kegs did this. They were my first lagers so I was planning to do the old standard 6-8 weeks since I have the room.