Can I secondary 5 gallons of Apfelwein in a 6 gallon carboy?

[Ben_Persitz]

I am making a 3.5 gallon Pilsner and 3.5 gallon Hefeweizen sunday and I will have my two 6 gallon fermenters tied up.

I have 5 gallons of apfelwein sitting in a 5 gallon better bottle. I will need to lager my Pilsner obviously, and I don't want to lager it in a 6 gallon carboy as I'll have so much headspace.

Would it be okay to switch my 5 gallons of apfelwein into a 6 gallon fermenter and let it age for another few months or will that gallon of headspace be deterimental?

 

[Ace_Club]

How long has the Apfelwein been in the primary? If it's still bubbling the airlock, then switching it to the larger carboy shouldn't be a problem because the produced CO2 will push out the oxygen. If it's pretty much done with fermentation, then you can either purge the oxygen (assuming you keg and have a CO2 tank) with CO2 or you may be better off just bottling/kegging and letting it age in there.