Originally Posted by unionrdr
The problem with us comes in insomuch as we brew 5 & 6 gallon batches.
thus the 5 and 6 gallon carboys. if i go to secondary w/ a five gal batch, i rack from the 6.5 gal to the 5 gal carboy. as far as headspace in primary, it's not really an issue if you have 5 gal in a 6.5 gal carboy due to all the co2 produced during fermentation. eventually that co2 will mix in with the air, thus the need for a smaller vessel with less headspace for post fermentation additions or long term aging.