I ferment 11 gal of wort in a Speidel 60L fermenter. I am wondering if enough CO2 would be created by fermentation to purge (2) 5 gallon sanitized cornies of oxygen. I envision collecting the CO2 via tubing to liquid out of corny #1 with a jumper from corny #1 gas in to liquid out of corny #2, then gas in of corny #2 into an air lock of some sort. It is still a design in progress. I have been doing closed transfers using a CO2 tank but my supplier of CO2 refills went out of business. I will need to drive a distance for CO2 to serve my beer.