I have a two gallon test batch of cider about ready to bottle, but I have an empty corny keg and nothing to put in it right now. Is it OK to keg 2 gallons of cider in a 5 gallon keg? Will it carbonate?
not speaking from experience, but pressure is pressure so i can't see why not, and i've heard of others doing it with no problems. i imagine you will want to be sure to bleed out as much air as you can. if in doubt try the bottling/kegging forum it is very helpful
I made a pumpkin ale a few months back and after racking a loss due to pumpkin sludge there was only 3 gal when I racked into my keg. It carbed perfectly and tastes great. As said above, make sure you bleed out all o2 before you seal.