That's really cool.
Yeah, its a pretty good method. I've been doing a lot of mental gymnastics over whether I can eliminate even that minimal o2 exposure.
So you're using 3 vessels? Fermentation vessel, dry hop keg, serving keg? Purging all 3 with fermentation co2?
I was talking about this elsewhere but I've sort of gotten some analysis paralysis. If I could have my druthers, I would:
1. Dry hop without introducing o2.
2. Dry hop after fermentation ends.
3. Dry hop for only 2 days.
4. Dry hop loose.
5. Leave all debris in the fermenter
6. Spund.
But a lot of these goals conflict with one another. So as far as I can tell, the best 3 options are:
a) dry hop and spund with 10 or so points left, then cold crash to drop out yeast etc and transfer to fermentation purged serving keg with a floating dip tube. But this conflicts with 2 and probably 3.
b)Keg hop, either combined with spunding or with the hops placed prior to purge with fermentation gas. But this conflicts with 3 and 5.
c) what I understand to be
@HopsAreGood 's 3 vessel system. I think this would only conflict with 6, and given the o2 free nature, 6 is less important. I'm a bit leery of 2 transfers being the best way to eliminate o2, but the logic is there.
So its everything has a trade off and we have to figure out how to balance those issues. Every time I decide on a method I change my mind shortly after, lol.