Ahem....throat is now clear. We have fermented our beer to primary conclusion.
It does contain en-trained gas which is CO2. I am of the school where we now
secondary (i.e. lager) in a CO2 filled Corny Keg. We rack from primary vessel into a keg where some of
the en-trained gas is released. This Gas is heavier than the oxygen in the canister
and displaces oxygen upward toward the keg pop off vent. After racking from primary
to keg, I apply gas under pressure from my CO2 cylinder to the vessel forcing
the lighter oxygen even harder against the pop off valve. I then pop off the
valve releasing the lighter oxygen from the beer keg. MINIMAL exposure of the beer
to oxygen. At this point the keg is purged and ready to lager....reduce temps and
enjoy good beer.
(Sound technique governed by physics? IMHO)