Fermenting under pressure/sealing keg lid with O2 instead of CO2/harvesting yeast?

[1Mainebrew]

So I have read about the importance of pure O2 for good yeast health and vigorous fermentation. I have also been reading about fermentation under pressure in a keg and the perceivable benefits from that, in particular- ease of transfer in an oxygen free environment from the time you pitch your yeast to the time you pour your beer and yeast harvesting. So could you conceivably rack to a corny keg for primary and seal the keg with O2 instead of CO2 and shake the keg for a minute to get pure O2 into solution then bleed the pressure, pitch your yeast, seal the lid with CO2, attach your blowoff tube and have yourself some happy, healthy yeast for easy harvesting, then after fermentation transfer from fermentation keg to serving keg from beer out to beer out? Does this seem like a decent idea/way to go about it or is a diffusion stone still the way to go with pure O2? I haven't fermented in keg yet but I would like to try it, and was trying to think of the best way to go about it with all the potential variables discussed with regards O2 and yeast health/harvesting. Thanks!

 

[scone]

There was a guy with a blog on here that did a bunch of o2 diffusion experiments. I can't find the link at the moment but his results went something like this: a diffusion stone is NOT the best use of bottled o2 in terms of getting it in solution. If you've got the o2 setup, the best way to do it is to hit the headspace with pure o2, and stir using a drill/wand setup for a minute or two, perhaps hitting the headspace a few more times with o2 as you go. It's the same reasoning as why you shake your keg to get the co2 to dissolve faster if you're trying to force carb quickly. You have to maximize the contact between the o2 and the wort. If you use a diffusion stone, most of it just bubbles to the top before it can get into solution. Jamil did a podcast on o2 methods, but I don't believe this was among the techniques he tried.

 

[ikonis]

Using a diffusion stone recirculates the liquid to the top so it is constantly hitting the surface and exchanging air from the SURFACE of the liquid.... so Yes, pure O2 is perfect for this. As it will blanket the surface with the wort, and as that will have much more O2 than just air will, you get more O2 into the wort. So yes, you can fill the headspace with O2 and shake. I personally ferment under pressure and use an inline oxygenator straight from the plate chiller into the keg. So I chill the wort on the way to the keg (that already has the yeast in it). And inject O2 directly into that stream. After that, the wort never sees the natural atmosphere.