On guy in my brew club recommended pre-crushing all the pellets, putting them in a ziplock bag, this way you can squeeze the 02 out without any voids of O2 between the pellets, purging ziplock bag with CO2, then purging your FV so a layer of CO2 is on top of you brew before adding hops. Then dumping them in. Close up the FV and purge again.
There will still be a lot of O2 entrained between the pellets when you go to actually put them into your fermenter. When you go to open the ziploc bag, air will rush in, ultimately defeating the purpose.
Idk how efficient the crushing will actually will be to minimize o2. To me the nitrogen purged pellets from Yakima chief and even Yakima valley hops seem like better options than crushing the hops and exposing more of the hop material to oxygen.ziploc bags them selves can have flaws and after pulverizing the pellets in the bag youre bound to put holes in the bag. Seems like a lot of work for a possibility of more o2 pickup.
I agree with your comments.
The best I've come up with is this. I do this the day before I dry hop.:
1. Get a tall mason jar or other airtight container and dump your hops in. The more headspace the jar has with your dry hop charge in it, the better.
2. Remove your gas disconnect from the hose on your tank so that it's just an open ended hose. If you don't have means to remove the gas disconnect such as a quick connect, this method won't work for you.
3. Back the regulator off (all the way counter clockwise) such that when you open the main valve on the tank, no CO2 flows out.
4. Insert the hose into the jar with the hops in it. If you can wiggle the hose to the very bottom of the hops, all the better.
5. Slowly!! Turn the regulator in the clockwise direction until the flow of CO2 starts. If you turn it up too much too fast the hops will become violently airborne and you'll have hop dust from a$$hole to breakfast. Ask me how I know.
6. Let the gas flow for 30 seconds or so to flood the jar with CO2.
7. Quickly remove the hose and cap the the jar.
8. Perform steps 2-7 again once more right before you dry hop.
I believe this method allows the CO2 to displace the O2, and over night diffuses with/dilutes any remaining O2 within the hop pellet crevices.
I also believe that this, combined with a slow trickle into the gas post (if fermenting in a keg) when dumping the hops from the jar into the fermentation keg keeps O2 exposure to the beer at very low levels due to the "updraft" of CO2 coming out the fermenter. Janish talks about this in his book actually.
You might be able to use the method above with a ziploc bag in place of the jar.
The next step up to baller status is something like this, of course: