I cannot seem to make very old (about a year) yeast cultures on Yeast Malt (YM)
media to grow again.
They are mostly industrial strains of S.cerevisiae and a few wild yeast too.
I've tried streaking out on
YM agar media as well as liquid cultures of YM (pH adjusted to 5.5) media
supplemented with vitamins too.
Any ideas will be greatly appreciated!