Strange yeast starter

[ronjonacron]

So I've been doing the method of yeast starters where you make a huge starter, split it (to save half for your next starter) and then do another run with the other half for your current batch. This is nice because you don't have to worry about washing or pitching slurry calculators and what not. I've been doing this for a good while with pretty good success. Here are a couple images of a weird discoloration. Is this anything to be concerned about before I pitch this?

also, this this will only be the second batch on this particular purchase of yeast, so it's by no means old. Also, it's wyeast 1450.

View attachment 1420303807493.jpg

View attachment 1420303824519.jpg

 

[IslandLizard]

I'm interested in the answer too. I've also experienced yeast darkening. I think dead cells are darker, but that looks severe and so well separated.

Is that starter beer you've got on top of the yeast or sterilized water?
I think it's better to fill the jars all the way to the top to eliminate air/oxygen.

I pour off my starter beer into a sanitized jar. Split the yeast, then fill the jar(s) up with the saved starter beer. I've gone from pint jars to 1/2 pint and now use little 1/4 pint Mason jam jars. Saves a lot of space in the fridge. They're in a box, stacked and empty space is padded, so they can't tip over. Labeled on the lid.

 

[Barley_Bob]

My short answer is that I have no idea.

But I've observed this with my own yeast, and I've always just rolled with it. No trouble so far... If there's a microbiologist out there, I'd love to learn more. I've also noticed some yeasts seem to do this more. Charles Wells (WLP006) jumps to mind. It seems dark anyway, and mine, at least, tends to have bands.

 

[IslandLizard]

BTW, I have Belgian yeast that is darker than your dark layer. Still grows well, just got two 1.5 liter starters from them, with a thick layer of dark yeast on the bottom.

 

[ronjonacron]

Yeah, I usually fill up the pint jars and store them full. I made a mistake both times when converting from ml to oz, whoops. Guess I'm not qualified to do that in my head, though at least I'm consistently wrong.

The second step, the one with the dark stuff, grew and krausen ed just fine with nice fermention, so I know there's healthy yeast in there. I just thought the coloring being so well separated was really odd.

Edit: it's starter beer on top. I was under the impression that's where yeast was happiest for short to mid range storage.