Random fermentation increase?

[Bob-O_Brews]

Brewed a pale ale 11/25. SG: 1.061. Checked on it Tuesday (12/9) and it was 59 seconds between bubbles at 72F. Fast forward to today (Friday). It's now at 69F and 33 seconds between bubbles. Wtf?

I used a WLP051 starter. Had a nice solid start that gradually slowed. Seemed like every other batch before. Figured yeast would be on clean up duty but apparently they took a break, and then came back to work.

I have a lot of faith in my sanitation and WLP051. I'm not sure what to make of 3F drop with obviously increased fermentation. Attenuation is my friend so I'm going to let it ride.

Anyone seen this before?

 

[ThunderpantsBrewing]

Airlock activity can be caused by all kinds of things, including temperature change, so I'm guessing it isn't continued fermentation, just doing funny things because of temperature.

 

[flars]

Time to take a SG sample for a taste and have a look to see if a krausen is present.

 

[Bob-O_Brews]

Thanks guys. This morning it was back to 74 seconds. Sounds right to me. It's in a carboy, so I know the krausen fell out over a week ago.

Was planning to rack and dry hop this coming Tues. I'll check gravity then to see if I should proceed.

I'm still a bit confused though. A drop in temperature should mean less airlock activity, or in extreme cases suck back. Right? In addition, the Imperial Stout sitting right next to it showed the decrease in activity I would expect after 3 days.

Again, I believe in yeast. Confident with my sanitation. I'm not worried. I've just never seen it before.

 

[flars]

I just dry hop in the primary. I use pellets, not whole leaf though.

 

[Yooper]

I'm still a bit confused though. A drop in temperature should mean less airlock activity, or in extreme cases suck back. Right?
.

Maybe. Or, the barometric pressure rose. Or fell. Or, the ambient temperature dropped faster than the temperature of the beer, creating a vaccuum. Or something else entirely.