I’m brewing a Scottish Ale and after 2 weeks in primary fermenter, the beer was within 2 pts of target terminal gravity. Transferred to secondary (glass carboy). Fermentation started again and has been bubbling once every 40-50 seconds for almost 2 weeks. Has been in secondary for 24 days at 68F. Has anyone experienced this or have recommendations? Cheers!
Have you checked the gravity? Is it really fermenting again or is it just CO2 coming out of solution? Was there a temperature change between primary and secondary? I have used WLP028 quite a few times and have never seen this. I don’t transfer to secondary, though.
Hopefully, it is just CO2 offgassing in a warmer environment. Next time I would ditch the secondary (use of a secondary is pretty outmoded advice for most beers and just opens up more chance for oxidation or contamination). The key on final gravity is that the gravity is stable and not changing over a few days - that is what tells you the beer is done. Target gravity is helpful, but essentially meaningless.
Best of luck with the beer and I hope it has not developed a contamination - continued airlock activity for such a long time does not bode well, unfortunately. Is there any unusual looking pellicle forming on the surface?
It’s probably just releasing Co2 that is in solution. Have you checked the gravity again since you racked it?
It could be a lot of things including a wild yeast infection, off gassing, continued fermentation, etc. The only way to know is successive samples reading the same thing telling you it’s done fermenting or a changing gravity telling you it’s still fermenting.
Generally speaking wlp028 has a solid dependable fermentation profile which has led to it being a common choice as a house strain for early craft brewers.
There’s an easy way to test if it’s infected or if it’s normal off-gassing: just taste it!