dry hopping restarted fermentation?

[ApresSkiBrewer]

Just curious if any of you have experienced this....

I have a belgain IPA in the carboy, and after 15 days in primary, I threw in an ounce of pellets to dry hop with. I started the fermentation at 68-70, and as the first week went on, bumped it all the way up to 78-80. I left it at 78-80 for the second week. All visible fermentation was complete (no airlock movement/beer cleared nicely) and then when I dry hopped, i removed the temp control and the beer temp fell to about 64-65. It has been 7 days now,but ever since the first day that I dry hopped and turned off the temp control, I am getting a little airlock action. Probably... one bubble every 45 minutes or so. (I know this because the carboy is near my computer/where I sleep, and I can hear it in the closet.)

So my thought is... well, maybe some of the yeast was stressed at such a high temp, and that cooling actually allowed for a little bit more of fermentation to carry on..? That doesn't seem to make sense to me.

or, possibly, I introduced an infection when I dry hopped, and that is causing the airlock action.

I don't want to remove the airlock until I plan to keg, to avoid another possible infection... but I'll smell/taste/take gravity then... and hopefully all is well.

I was just wondering if anyone had any idea of why I would get some activity after the beer had been pretty much still for 8 days? I'm not super concerned, just curious.

[6thstreetbrewer]

probably some residual co2 coming out of solution because the hops agitated it. Kinda just guessing here. Maybe you introduced some o2 that was in the hops (although unlikely with the pellets) and that is coming out with the co2? Maybe someone thats not flying by the seat of their pants will chime in.

[ApresSkiBrewer]

Yeah 6thstreet... Maybe the pellets created nucleation sites for the Co2 to gather and release.... but the drop in tempurature should make Co2 more soluble into the beer... and hold it in a touch better. That's why I asked, I have no clue either... I might keep guessing until we hear something substantiated.

Lucky you have something to fly by, because I don't wear pants.

[Fritz Eye]

Yep, this happnes to me all the time when I dry hop.
I even get a bubble evry 10-15 seconds or so. But after a week of this, there is no real change in the FG. But that is just me. I just make sure before I dry hop the majority of my fermentaion is done. Check out Tasty on Brew Strong, he mentions his schedule on this.
The truth comes from the hydrometer.
Hope it comes out great..
Cheers.

[ApresSkiBrewer]

Thanks Fritz Eye.

Fermentation (as far as I could tell...) was definitely done... including dry hopping time, its been in the primary for 22 days now (getting ready to keg tonight prob). I don't like taking too many hydrometer samples, because of the risk of infection.... so if things look normal, I usually give it 2-3 weeks, and always seem to hit (or at least close enough) my TFG.

I wasn't too concerned, just glad its not an indication of an infection.

[TapItGood]

It happens to me too when I dry hop in the fermenter. Possibly from the intoduction of a little more oxygen that those beautiful yeasties need to ferment more. Tasty what do you think, Why does dry hopping in the fermenter get those yeasties going stronger?