Harvested yeast concern

[Oldskewl]

I harvested some Bells yeast out of the latest batch of Oberon. I made a 0.25L starter and then stepped up to 1.75L starter and poured off 0.5L to save for another batch. Everything seemed to go well and my current beer fermented ok from 1.067 to 1.015. Anyway the 0.5L sample in the fridge is in a pint mason jar and I noticed after a week or more there were quite a few bubbles(1/2" thick of tiny bubbles) on top of the wort. The jar had pressure built up. So I released the pressure about 3 times over the last week. It keeps forming bubbles around the perimeter of the jar. I also notice small pieces of yeast going to the top and falling back down. Almost like they are going to the top for air. This doesn't seem normal. Would you recommend pitching it? I'm guessing it may be infected.

 

[WarEagleBrewer]

I had almost the exact same thing happen with some harvested Bell's yeast. It was like it started fermenting again in the fridge. Eventually though, it stopped. I used it in my last beer and it was fine. No worries.

 

[Oldskewl]

Thanks for the feedback. It looks fine, just never saw an ale yeast keep fermenting at fridge temps.

 

[WarEagleBrewer]

Yeah, first thing I though was INFECTION, but there was nothing growing on it, and it smelled fine.