Pellicle on Harvested Yeast

[jescholler]

This past Sunday I harvested some yeast from an ESB after 2 weeks of primary fermentation. I just poured the slurry into mason jars. Two days later when I went to decant the beer and top off with boiled cooled water, I noticed a lot of bubbles on top of the beer. It reminded me of pictures I've seen of pellicles. It was somewhat chunky when I poured off the floating stuff. After adding the water, I shook it up and let the heavy stuff settle out before pouring into new mason jars. Now, one day after doing that, I see more bubbles. I don't think the bubbles are coming from the slurry. It seems more like they just never sink.

My question is, what are the chances that the yeast is infected? Two days for a pellicle to form seems damn fast. What else could the bubbles be? Maybe 2 weeks of fermentation wasn't long enough, but the fermentation was strong and the gravity was on the low end of what I expected.

 

[avidhomebrewer]

A pellicle does take more than 2 days to form, from what I've seen. I bet the yeast is still actively fermenting what residual sugars are left in the sample.

 

[barroomhero1234]

You should vent those mason jars, they might not be infections but if you do see some activity then it's nit worth getting seriously Injured. One way I suggest to see is if you have an infection would be sanitize the outside of the jar, opening it flame the opening and give it a smell, if it does not smell off ie sour etc you should be fine and the yeast just got roused up. If you are not sure don't reuse it, no use pitching a bad yeast and waisting a good batch. The infection would become amplified if you pitch a even slightly infected yeast.

Good luck!!
Scott

 

[jmferris]

What sort of an ESB? A lot of the British-style Ale yeasts have a tendency to top-ferment and be very flocculent. What you are describing actually sounds a lot more like how I would hope for my ferment to start out, as opposed to an infection.

I built a starter last night using WLP002, and can already tell you that I am getting the little white bubbles on the top of it - and that was only after about eight hours.

 

[jescholler]

You should vent those mason jars, they might not be infections but if you do see some activity then it's nit worth getting seriously Injured.

I've had the lids loosely on since I know harvested yeast has a tendency to off gas.

What sort of an ESB?

I used Wyeast American Ale II (WLP051) since that is the yeast I use from batch to batch. I don't brew often enough to keep more than 1 strain on hand with enough viability.

I think it was a false alarm because I kept three samples, and the bubbles have disappeared in one of them (the one with the least yeast). The bubbles have lessened in the other two. So it was probably just a little fermentation going on.