Low Oxygen Dry Hop

[Dem Castles]

Cold crashing now from 90 degrees to 65 degrees over a day or so.
Yeast-
Omega Hot Head Ale Kveik

Here's the dilemma, I was hoping to dry hop using a sight glass/butterfly valve to minimize oxygen exposure.

Due to my kegerators height, I would have to move the fermenter out and then do the dry hop.

Questions -
At 5 PSI in fermenter, can I close the butterfly valve, add the Spike sight glass full with 1.5 oz of hops.

Purge hops at 2 PSI, open butterfly valve to drop them in. Close butterfly valve, remove sight glass, add manifold back on and then increase fermenter to 8 PSI?

 

[Vale71]

Sure you can although it will take quite a lot of purge cycles to get the residual O2 in the sight glass down to acceptable levels.
BTW the setup you have is extremely dangerous. By forgetting to open the butterfly valve you could accidentally disable the PRV and if pressure where to keep building up an explosion is the only way that pressure could now be released.

 

[Dem Castles]

Thanks for the reply,

Are you saying the only danger here is forgetting to open the butterfly valve?

Another option is to decrease PSI to 0 by turning off co2 and releasing all pressure via PRV.

Then proceeding with the sight glass dry hop.

I know if you don't have co2 in the vessel when cold crashing you can create a vaccum, but if the temperature is already established in the 60s does it matter if there's no pressure within the vessel for a few minutes?

 

[NewJersey]

I also ferment in a spike flex+, but in a stand-up freezer. Because of your thread, I'm going to copy you! I already have an extra butterfly valve (don't ask) so all I'll need is the sight glass.
How many ounces of hops could fit in the spike sight glass and be easily dropped?
I think I can remember to open the valve when don't.
Also would there be any harm in just leaving the sight glass on for the rest of fermentation? (With my spunding valve and prv on top)

 

[Dem Castles]

I also ferment in a spike flex+, but in a stand-up freezer. Because of your thread, I'm going to copy you! I already have an extra butterfly valve (don't ask) so all I'll need is the sight glass.
How many ounces of hops could fit in the spike sight glass and be easily dropped?
I think I can remember to open the valve when don't.
Also would there be any harm in just leaving the sight glass on for the rest of fermentation? (With my spunding valve and prv on top)

I did 1.5 oz of pellet hops in the sight glass and there's plenty of room for maybe a total of 3 grams.

I had to open and close the butterfly valve a few times to get all of them in but it does work. I will definitely be dry hopping with this method from now on.

Yeah just remember to keep that valve open and you should be good, as far as keeping the sight glass on, I am not sure.