I found a vial of White Labs WLP001 that expired about 4-5 weeks ago…what’s the probability there are still some viable yeasties in there?! I can throw them on the stir plate this weekend and start to step it up to see what happens, but curious what the sediment…er…sentiment is out there for a vial past it’s prime…? What say you?
I think you will be pleasantly surprised with how “old” yeast can turn out given they were stored at the right temperature and you make a starter. I had an Oktoberfest yeast that was probably 6 months past its prime. My LHBS discounted them 30% so I thought, ehh, what the hell. The yeast turned out just fine after a starter was made.
I personally think that yeast are tougher than we as homebrewers give them credit for. Especially if you give them time for a starter, i wouldnt worry about it. A 1 or 2L starter will be plenty on a stirplate without having to step up.
I’ve use quite a few smack packs that were 1-1.5 years old. The only thing I have noticed about them is that they take longer to start when I make a starter.