first use old yeast

Ingredients
1

I have a vial of WLP090, best by date Feb 15th - estimated viability 30%. Pitched into my starter last night at 5pm so been going about 13 hours. cant see any active fermentation…no krausen no noticeable co2 bubbles in the wort.

Ive never used a vial this old before, and wondering if perhaps its just a longer lag time with less viable yeast or its just likely dead.

2

Be patient, it will start.  I just sub-cultured two slants from a 13-month-old Scottish and Newcastle slant.

3

so its expected it will take longer-again, have not ever used yeast this old before.  thanks

4

How big was the starter?  Stirplate?

5

Yes.  Expect that it will take longer, but the results should be just fine.

You can grow viable pitchable quantities from the dregs of one bottle of beer.  Growing a starter from an older vial of yeast should not be an issue.

6

started to get active. IIRC, don’t think i’ve ever used yeast more than 2 months old- so learned something new.

thanks for the feedback.