How do you determine how much slurry to use for a starter? Mrmalty shows how much slurry to use to achieve the proper number of yeast cells for pitching, but does this take into account making a starter from your slurry?
How much slurry to use for starter?
- Thread starter player2ma
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Let's say you have 30mL of yeast solids from January 20th. This gives you around 2.6 billions cells per mL of viable yeast or 77 billion cells.
Put 77 billion cells into yeastcalc and it will tell you about starter steps. (For example a 1.3L starter will give you enough yeast for 5 gallons of 1.060 wort)
How come you are making a starter from your slurry instead of just directly pitching the slurry?
I've done this with old slurry. Older than about 6 months and I do a starter to make sure it's viable (it always has been)
Depends on a lot doesn't it? Age and volume of slurry, OG of beer, etc.
Yeah, that's why I was asking. I usually re-pitch slurry on the same day I rack the original batch. Occasionally I re-pitch after storing the slurry in a fridge for a week or two. I assumed that if one were re-using slurry after a few months, they would have rinsed the yeast to start with--in which case you can just treat it like pitching liquid yeast.
Subscribed, about to do the same thing.
woa, is the drop-off really that fast? i just harvested and washed some yeast this weekend, but i'm pretty sure i won't be using it for several months... almost seems pointless now.
i guess i could make a starter every month to keep the population healthy, but that seems kinda excessive. if i'm not going to use that yeast in the next 4 months, i'd be better off just buying a new smackpack when the time comes.
otherwise i might look into glycol & freezing.
anyone have any experience using 6+ month old harvested yeast?
EDIT: nevermind, did some searching, as expected the answers are all over the place - some say 6 weeks, others have used stuff from 6 months ago.
Stauffbier
Well-Known Member
I just used 15.5 ml of 4 month old, 2nd generation wlp001 that was rated as 27% viable to make a starter for a 1.050 amber. I stepped it up twice over 5 days and I got great propagation. It started chugging like a freight train after about 5 hours of pitching it in my amber on saturday night. It's still going really strong at this minute. I'll wash it again and do it again, and again (about 7 times or so).. 10% viability will likely still work just fine if you step it up slowly over a few days..
