What’s the age limit on your use of harvested yeast?
I brewed a dry irish stout 3 weeks ago using WLP004. The yeast was harvested from a previous batch in late May so I know viability was low. I made a 1L starter which was very active and ended with a nice 3/4 inch or so cake in my 1 gallon jug. OG was 1.053, fermentation kicked off a few hours after I pitched at 63 degrees. Kept the temps low for 3 days then let it rise to ambient of 68-70.
Only got 1/2 inch or so of krauesen at most during ferm.
Checked SG after 1 week and it was 1.018. Shook the carboy a bit to try and roust the yeast. Checked SG last Sunday, same and again today, same…
The beer tastes good. A little sweeter and not as dry as expected. I’ll definitely keg and drink it soon.
66% attenuation if my calculations are correct. Not great. Just for future reference…should I have done a 2 stage starter since my yeast was so old? I know some people say they don’t even try to use harvested yeast after 3-4 months.