Micro Derm infection? recycled yeast 4x

Everything I read says it is a micro-derm infection- white, powdery membrane floating on the secondary.

It was just a couple bubbles, with a white powdery insides look, in the third time I used the yeast. But that was/is still good beer. Now, this batch after 2 weeks in secondary, has a film over the whole top, streaks extending up the sides. I sucked some of the top layer into a glass to sample, not good. I guess I'll dump it. Or maybe I'll rack carefully from the middle and sample it again, nothing to lose, I can always dump the bottles and wash them. I already dumped the saved yeast cake.

I didn't do any thing to save the yeast betwen batchs except bottle some of the cake, as if it were beer, and then refirgerate the few weeks 'til making a starter for the next batch.

But, just what is micro-derm? I can't find any scientific use of the term, except for facial scrubs, and homebrewing. Is it a contracion/abreviation of dermatophytes, nail fungus? er what?

Pics? no hosting service, but I can PM some in a day erso.

Dunno...I had that cloudy/powdery weird stuff on the top of my wheat doppelbock...but the beer turned out just fine. You say "not good", but what does that mean? Are you sure the batch is spoiled?

Not sure if the whole batch is spoiled. I only tried the scummy top layer. It was reminiscent of a taster at the local HB club, that folks said was infected. Bileous? not tartness, not moldy or cardboard... but reminiscant of infection? why? sinus or tonsil pus?

I did study up on yeast life cycle. (haploid, diploid...) Seems they mostly 'bud', multiply dy dividing. But when they use up all their food, they also can convert to making spores. The spores survive bad times much better. Seems the yeast we buy has lots of spores, they last lots longer in storage. But yeast cake would be live cells. So, I wonder if the white is spores? It would be harmless if so, providing you don't eat a handfull if it. Just as a glass full of yeast cake won't taste like beer either.