Kickstarting 7 month old harvested yeast?

[rhys333]

Hey everyone,
I have some old top-cropped Wyeast 3068 in the fridge I'd like to bring back to life for the next brew. I have a lot of it in one mason jar, maybe 250ml (1/2 pint), and your guess is as good as mine on viability... 60%, 5%, who knows.

Obviously I need a starter, but do I toss all of it in a small starter just to freshen it up, then pitch all the yeast in the main batch (old and new)? Or do I make a large starter with a small amount of the old yeast to build up mostly new cells?

You input and experience appreciated.

 

[midfielder5]

That is pretty old: if it has dark cells (and not nice white cream) I would toss it. can you post a picture?

 

[rhys333]

That is pretty old: if it has dark cells (and not nice white cream) I would toss it. can you post a picture?

Thanks for replying. Here's a picture of the old yeast. It's still quite creamy. The darker layer you see was there from the start and due to the dark malt in the dunkel i harvested from. Guess i was off re amount. I have perhaps 100ml

View attachment 1424635851368.jpg

 

[midfielder5]

looks ok. Pitch it to a 500 mL starter, but I am not a pro. Someone else will chime in, or google around for YeastCalc which has step-up starter pages.