I have a 2 gallon batch scheduled that I’d like to put into a 2.5 gallon keg. Any problems with that?
If the keg is purged with co2, the presence of oxygen should be minimized. I generally fill all of mine with sanitizer and purge. I have had 1/2 gallons of head space due to beer loss : dry hopping or just because I’d rather collect wort that matches my OG, but may be off on volume.
No problems other than as already mentioned. I’ve used 5 gallon kegs for half batches before.
+1 and +1. CO2 is your friend.
Good to know.