Very Interesting Situation - Fermentation Restarted?

[B33rL0v3r]

So I brewed a batch and fermented in two 6 gallon carboys. When fermentation had slowed to a bubble every 30 seconds I racked into secondary. One carboy appeared finished as the CO2 krausen had settled completely and the other looked like it was getting there but still going a little. I racked the settled krausen into secondary with a hop bag full of hops and the unsettled into secondary with hop in no bag.

24 hours later and the unsettled/no bag dry hops carboy appears to be fermenting again. Its cloudy and there are chunks of yeast/hops moving about fairly rapidly inside.

Keeping in mind that this was the same batch and same strain of yeast Wyeast London Ale 1028 (although separate slap packs), what could cause this? Same fermentation conditions and everything.

Might i have added O2 into the mix when racking? Could the hops be causing a C02 release 24 hours later? Or might it just be fermenting again?

I haven't taken a gravity reading because I don't like risking infection, so I'm just trying to explain this. Why didn't the hop bag secondary restart? Might it still?

Anything and everything is appreciated here. Thanks!

 

[Kaz]

Bubbles can come out of the airlock for so many reasons, that I don't even pay attention to the bubbles. The only way to gauge the progress of fermentation is to take gravity readings. The fact that there is yeast movement inside the fermenter leads me to believe that it is fermentation you are seeing. How many days had this been in the primary? Dry hopping can introduce gas into the beer with the hops but that won't cause all the motion.

 

[PurpleJeepXJ]

I dry hop right at the end of fermentation in order to keep CO2 covering the brew and to force the O2 out. Kaz is right, the only way to know for sure what is going on is by gravity readings. You probably introduced some O2 and woke those yeast up.

 

[nefarious_1_]

It's possible you THOUGHT fermentation was over and, upon transferring, stirred/roused some yeast back into suspension and created a more noticeable fermentation. That coupled with the possibility of introducing some O2 during the transfer (as mentioned above) could produce what you're noticing.

IMO, you really shouldn't be transferring to a Secondary vessel until fermenation has stopped.

+1 to a gravity reading being the only way to guage the progress of fermentation.