Made a starter with some (~400mL) ale yeast slurry from my brewery and some light DME. Finished with no apparent fermentation issues, but after settling out, I noticed a dark sediment layer beneath the normal yeast layer (see picture). The slurry had, as far as I could tell, no hop/trub material in it. Could the dark layer be dead yeast? Or something else? The generation of the yeast strain was quite young, 4 out of an estimated 16, and the count itself had almost no dead cells present.
