Thanks for your reply but I see a couple of holes:
1) Opening the keg and adding the hops defeats the purpose of purging in a way. Maybe a quick lid opening is not that bad but in theory O2 gets in.
No, actually not. You're then using the CO2 from the fermenter to purge whatever might have gotten in there with the hops.
2) Why would you need to suspend the hops when a transfer to the keg will be for spunding or just force carb? Either way the fermentation is largely finished at this point.
Well, it was to keep them from creating nucleation points for bubbles to form. Maybe that wouldn't be a big deal if you just let the bag sit on the bottom of the keg.
3) I ferment in a wine fridge so there is no way to run anything from the fermenter. I could just open the lid, drop the hop bag and purge again with tank CO2 but I am not convinced the oxygen would be pushed out given the way gasses mix.
If you purged enough times it would be. But maybe that's no desirable. That's why I went to using fermentation gases.
Since I am spunding, maybe the residual fermentation would eat up most of the oxygen from the lid opening and we can just call it a day? It is a conundrum with the use of corny kegs that were not designed for this use. Maybe a little O2 just has to lived with for dry hopping at the homebrew level?
If you're racking with a few points remaining, that would be a reasonable way to try to scrub oxygen that gets in with the hops.
As far as your fermenting in a wine fridge and can't get the gases out, let me suggest two ideas that might allow that.
One is to drill a hole in a spot not used by the cooling coils and run tubing out of that. Here's how I did that in my small ferm chamber:
The second way, maybe more elegant, is to use a bulkhead shank to pass the CO2 from inside to the outside. I did this on my large ferm chamber to both connect CO2 so I could force carb kegs inside it, as well as pass CO2 out of the fridge to either monitor fermentation, or to run it through a keg to purge it.
The shanks use MFL fittings so you can connect tubing, CO2, whatever. I also use those on my keezer so I can keep the secondary regulators outside but feed the gas to the inside:
You can get them from the Chi Company:
http://www.chicompany.net/index.php...46_425&zenid=b3da20325e896ef6f4ff3d86b06d3da7