Is an airlock really required for secondary?

…Especially for lagering in a fridge? I am short on carboy space, but have some kegs coming. I was thinking of just doing the secondary in those, rather than buying some more carboys at this time. I intend to purge with CO2 of course, when racking.

No airlock necessary in a keg, but be sure you’ve reached a solid FG before racking.

If there is still fermentation activity when you rack and you seal the fermenter the pressure could send the bung flying. follow shadetrees advice and make sure the fermentation is done.

If you have a keg system there’s no reason to lager or bulk age in anything other than a keg. The only reason you’d need a true secondary with an airlock is if you’re adding fruit or some other fermentable.

And yes, you should always make sure attenuation is done before you rack into ANY secondary vessel, regardless of what it is.

cool, thanks everyone!