I just made my first batch that I plan to keg instead of bottling. I have a new 5 gal corny keg but unfortunately it looks like this batch is going to only turn out to be about 3.5 gallons when all said and done. Question: Is there any problem kegging 3.5 gallons in a 5 gallon keg? Would I be better off getting a 3 gallon keg for this batch?