Well, it sounds like you have a reason. I seldom use a secondary but dry hopping is an exception for me. I cold crash the primary, xfer to secondary, dry hop and crash again.
If you wait until the beer & vessel have returned to room temp then there is no vacuum, hence no inrushing of air when the stopper is pulled. I generally remove the FV from the fridge the day before I plan on bottling. I also do my best to purge the headspace with CO2 any time I have the lid off, i.e. sampling, dry hopping etc., I realize there will always be some infiltration of air, but every little bit of purging helps some. For those using conicals with sediment jars, I recommend purging the jar with CO2 after harvesting and before re-attaching to the FV, I know that seems obvious, but it took me a while to think of that one, but I was one of the short bus kids.
I seldom dry hop, but when I do it’s in the primary with some fermenting left to do. Using the stainless mesh canisters for the hops I can even keep the yeast clean enough for harvesting and repitching. And I’m not using a conical either. If it’s at all possible with whatever fermenter one is using, then I don’t see a need for transfer.
I don’t care for the effects of doing dry hops on yeast. To me, that’s worse than any possible oxidation.
^^^^
Okay, there’s a reason! 
Yep! It’s my reason and I’m sticking with it!
Denny, you king of podcast. There was an presentation at MBAA about hop creep. You can listen to it here. http://masterbrewerspodcast.com/098-dry-hop-creep You do not have to be a MBAA member to access the podcast.
Keith, I have experienced refermentation after dry hoping after reaching terminal gravity. My only explanation is that it is availability of oxygen and enzyme activity from dry hops. Granted I was using 3.5lb/BBL.
Robert, you are correct in all the points what you mentioned. Here is a presentation from last year Malt U about this topic. https://bsgcraft.com/resources/Announcements/FAN%20and%20Flavor%20impacts_Malt%20Symposium%202018.pdf?_ga=2.114860551.1029554665.1563732014-1038012913.1563732014
Denny - I have definitely experienced hop creep … very much in unfortunate instances. Think of a $50,000 recall and you will understand how unfortunate. At YH we would force age, force ferment, and inventory EVERYTHING. I’ve seen it happen on more than one occasion. FYI I also believe in biotransformation… that’s also a very real phenomenon. Just sayin’. 
The pod cast Thirsty Monk mentions is a good one. Check it out.
Besides podcasts, there are some old fashioned papers from 1893 that cover the topic pretty thoroughly; in fact I don’t think I’ve seen anything really significant added to the subject since! Then some more papers around 1939 (publication delayed by war) rediscovering and reexamining and confirming those. Then the whole thing rediscovered again now…
Back in the 19th century, dry hop creep was depended upon and taken for granted. It was the primary reason for dry hopping. It ensured full attenuation and the elimination of sugars unfermentable by culture yeast that might feed spoilers.
Flavor and aroma weren’t considerations for dry hopping then; the beers were sufficiently aged that hop character would be nearly absent by the time of release. The only other function was providing tannin to complex with protein and help clarification. Like the modern use of gallotannin in the aging tank.
One thing the original studies note that I haven’t seen (might have missed) addressed in the recent work is that seeded hops may contain more amylase than seedless (IIRC this assertion of the 1893 study was questioned by the 1939 work.) I wonder if some hops today might be deseeded prior to pelletizing, leading to inconsistent results in producing dry hop creep. Maybe there are other differences in modern varieties as well.
Sent from my iPhone using Tapatalk
[/quote]
Well, it sounds like you have a reason. I seldom use a secondary but dry hopping is an exception for me. I cold crash the primary, xfer to secondary, dry hop and crash again.
[/quote]
Same here, Denny. I tried dry hopping in the conical so I didn’t have to transfer and had a hell of a time kegging the beer from the conical (even after burping out most of the dry hops before starting) because iI kept plugging up my inline screen. I only now transfer IPA’s to a secondary (more precisely a brite tank), purging the hell out of the vessel prior to the transfer. Makes things go a lot easier at kegging time which is a closed transfer. Plus, the transfer seems to rouse the yeast a bit which adds a bit more CO2 to the head space.
Like Denny says, I do the best to minimize O2 pickup then don’t worry about it.
Thanks, Leos. I’m familiar with the info in there. It’s not that I think hop creep doesn’t happen. But i dp think that homebrewers re too quick to call hop crerrp when something unexpected happens. There’s too much that isn’t understood about it.
Keith, I’m not by any means questioning that it happens. But I am questioning how ubiquitous it is. And it appears that I may have stumbled on a way to prevent it, at least at the homebrew level.
For what it’s worth, I haven’t experienced oxidation with large amounts of dry hopping during fermentation. I have experienced almost instant oxidation, however, after keg hopping with whole leaf.
Its great that the decision is so clear for you. I don’t care for the flavors I get by dry hopping during fermentation, it’s not an option for me. I now cold crash the primary, dry hop in a CO2 flushed secondary, crash again, then keg. Works for me.
It’s style dependent, for sure, but I like the results for NE IPA types of beer using either 1318 or WLP007.
Dry hopping with pellets, directly in the primary after fermentation is complete and 5 days before cold crashing, hasn’t caused oxidation issues for me either. However, I’m still suspicious of the kegging step even with a completely purged and closed transfer, since it seems like there is a marked decrease in hoppiness after only 2 weeks. I’m planning on moving to spunding for carbonation to test if I can detect a difference.
Sounding is something else I can’t do because I can’t control my schedule well enough. I use pellets for everything 99% of the time these days.
Oh there are so many ways to oxidize a beer!
I’m pretty sure this is a bot. Reported it earlier and thought it was gone but it’s back.