Purge headspace after dry hopping

[Alf34]

Hello brewers

I'm about to dry hop post fermentation for the first time, now that I got a pressure fermenter that I can purge after dry hopping.

I was wondering how many times should I purge the headspace, and at what psi. I am aware that it takes many cycles at 30 psi to completly purge the headspace of oxygen, but what is for you reasonable in this case?

The idea is to quickly open the fermenter, throw in the hops loose and close it, no more than 5 seconds in the end.

Thanks for your answers!

 

[HM-2]

Before I obtained a hop bong, I would remove my gas post, hook up a CO2 tank at barely over ambient pressure to the liquid post (swapping the gas QD on my tank with a liquid one) and slowly pour pellets into the fermenter through the empty posts slot using a 1" necked funnel that I epoxied to a gas post screw threads (basically took a spare QD I'd mangled the post seal on and drilled it out). I would then fully purge head space 4-5 times at 10PSI.

I don't think it's going to be zero oxygen, but it certainly never seemed to introduce enough to cause oxidation, even in very heavily dry hopped beers.

 

[mac_1103]

I am aware that it takes many cycles at 30 psi to completly purge the headspace of oxygen, but what is for you reasonable in this case?

Depends on the volume of the head space. There are numerous threads on the topic. You might find this post (with chart and table) from our resident beer math nerd @doug293cz helpful.