Oxygen exposure

I have never dry hopped before this week. Last week I checked to see if my fermentation was complete. I opened my bucket and took a hydrometer reading. It was still a bit high. So I closed it up and let it go for a few more days. This week I opened it up again and added my hops. I thought, when I was not done fermenting, any O2 I let in during the hydrometer reading would have been pushed out with the completion of the fermentation. But now that I opened it up again and added the hops, the fermentation is essentially complete and so the O2 that went in will not be displaced by the CO2 from fermenting. The question here is, should I have concern over the O2 that gets in when dry hopping? Is exposure to O2 really a problem? Should I just not worry and have another homebrew?

O2 is definitely a problem when dry hopping as it absolutely kills hop aroma after a few weeks. The good thing about adding dry hops to a fairly young beer is that it is full of CO2 and the hop particles provide nucleation sites which cause the beer to release large amounts of CO2. So I wouldn’t worry too much about it, but definitely do whatever you can to minimize oxygen exposure from this point forward.

What I do is quietly drop in my hops after the krausen drops. Just crack the lid and slip in the hops. Give it another 5 days or so and then check your gravity.

Maybe being a kegger we are luck as to rack quietly into the keg, toss in the hops, in a tea ball of course, then hit it with CO2 to purge and seal the keg… Whew…. Sneezles61

I throw more in the keg but I like to add some dry hops to the end phase of the fermentation. I stopped adding to the fermenter when I started kegging but since have started again and like the results.

I would like to know of yer perceived flavor/aroma thoughts… I haven’t done any fer a long time while fermenting… Sneezles61

I don’t know if its true or in my head but the aroma seems to last longer I guess I could add them all at once to the keg. What I have started doing with all my additions for my IPA is layering them in. No more than 50% bittering at 60 minute then a 30 20 10 and 0. I figured I would try layering the dry hops also. Everyone loves my Brew Cat IPA so I figure why change.

1 Like

I could be wrong but I think this has some merit. I believe co2 is heavier than o2 and also air as a whole. Again I could be wrong but because of this I don’t think oxygen would get into the fermenter unless it’s forced or it’s filling a void. So as long as you aren’t moving your fermenter while it’s open I would imagine you’d be ok. Hopefully others will comment on this because I’d like to know if this is true, but it seems logical.

I agree that’s why I’m not worried when I open my bucket for a peak, a reading or to throw in some hops

Yes you are correct, the specific gravity of CO2 is more than O2…. It isn’t much tho… Sneezles61