It’s quite the conundrum, but basically all methods we have tested and verified use active yeast and spunding. Since we have to break our purge to add hops, and since we know our purges are far from perfect to begin with, its a necessity to use those yeast for their oxygen scavenging abilities.

There are a few ways to go about this we will call them out here.

• Dryhop in the fermenter a day or so before transferring to spund – We are aware of certain yeasts having “issues” with hops.
• Allow fermentation to 95% complete, then dryhop and add sugar to naturally carbonate in the keg – This may alter alcohol content and overall flavor
• Dryhop in spunding keg -You would complete the standard fill with sanitizer and CO2 push, Switch CO2 to liquid out, lower pressure to 2-3 psi. Crack and leave open the PRV, and remove the lid, you should have a positive pressure coming from the bottom of the container. I recommend using a hop bag, with some dental floss tied to it. Lower bag, replace lid and tie floss off on to a handle and keep the PRV open for a minute or so. Close PRV, and now do your fermenter transfer. Once the dryhopping time is up, you can either chose to leave the hop bag in or remove. If you chose to remove, you will need to follow the same process as adding the bag only with the gas on the gas out this time (liquid out is going to stir up sediment, and foam the keg). Try and be as quick and gentle as possible.
• Find a liquid dry hop and dose inline from fermenter to spund keg – This is the method I personally use. I have custom dry hop extracts, and I dose inline to spund with a syringe. I consider this the gold standard solution. The problem is you need (or someone you know has to have) a brewers notice, to brew professionally.

I am sure there are many other ways to skin this cat, just keep in the forefront of your mind oxygen, and its absolute removal!