Looks like fermentation started up again after dry hops added......

[Teufelhunde]

I've got a batch of a Mosaic IPA that had appeared to be done fermenting, so I removed it from my mini-fridge and put it on the shelf at room temperature. Two successive gravity readings indicated that fermentation was complete with ABV around 6.5. I added the dry hops two days ago, and this morning, I am getting a bubble through the airlock every 20 seconds or so and I can look through the translucent bucket and see about 3/16 of an inch of foam on the top(I bagged the hops, and it is tan foam, not green, so it is not Hop material).....will hops ferment?

Lon

 

[jrgtr42]

Hops don't ferment.
It's either just offgassing, or coming up to a higher temp will occasionally get things started again.

 

[RealRayDizzle]

Hops don't ferment.
It's either just offgassing, or coming up to a higher temp will occasionally get things started again.

agreed, but hops can cause at least some yeast activity. Hop creep can be a problem, I have had this happen before when dry hopping in keg. yeast activates just enough to throw some off flavors. I had an IPA taste great, then a couple days later, have a odd buttery flavor.

Keep it at room temp at least a couple days to make sure yeast has scrubbed out completely. If you are bottling/ leaving at room temp, you should be good.

 

[balrog]

any change in temp or air pressure will cause the headspace to expand/contract, and temp will cause CO2 that is in solution to come out.

 

[eric19312]

Dry hop creep is a real thing caused by enzymes in the hops
https://beersmith.com/blog/2019/03/31/dry-hop-creep-over-carbonation-and-diacetyl-in-beer/

Similar enzymes are used to make commercial light beer and brut IPAs, although at higher doses. Pretty sure this is what you you saw.

The other thing that you will see with dry hopping is the pellets act as nucleation sites and the CO2 in solution (a little less than 1 volume at end of a room temperature fermentation), some of it will come out. ALso if your fermentation chamber was colder than your room some of that CO2 will absolutely come out of solution as CO2 is more soluble in colder beer.

 

[Day-Day]

Dry hopping creates some activity in there..whether it's yeast activity, residual Co2, or something else is hard to tell. If I'm not making a NEIPA, I try and make certain that it's hit terminal gravity before dry hopping, for many reasons, but for this conversation, so I can tell the difference between yeast activity and residual Co2 coming out of solution from dry hopping. If you dry hop during active fermentation, the lines get blurred of what is actually going on in there, at least from my perspective... and I'm talking completely about the visual appearnce of fermentation, not gravity readings.

 

[Teufelhunde]

Dry hopping creates some activity in there..whether it's yeast activity, residual Co2, or something else is hard to tell. If I'm not making a NEIPA, I try and make certain that it's hit terminal gravity before dry hopping, for many reasons, but for this conversation, so I can tell the difference between yeast activity and residual Co2 coming out of solution from dry hopping. If you dry hop during active fermentation, the lines get blurred of what is actually going on in there, at least from my perspective... and I'm talking completely about the visual appearnce of fermentation, not gravity readings.

Yeah, it has finally stopped all activity, and a check of the gravity shows that it did in fact go down just a wee bit.....I will check again in the morning, and if it has not moved over the past two days, will bottle it......