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Harvested yeast fridge shelves life

Discussion in 'Homebrewing' started by Ilanko, Aug 7, 2012.

  1. Ilanko

    Ilanko Savant (255) New York Aug 3, 2012

    Hi guys,
    I have harvested my yeast so many times, but every time i worry on how long can i keep my stash before its became deceased yeast ?

    My short experience lead me to three weeks from harvesting to re-pinching and 4 generation re-harvesting and pinching.

    How it's works for you guys ?
  2. I just used some harvested yeast that was 5 months old for a starter this past weekend. Starter took off nicely, and my beer is bubbling away well.

    So... at least 5 months.
    Ilanko likes this.
  3. Ilanko

    Ilanko Savant (255) New York Aug 3, 2012

    I forget to mention that my yeast bank is based on dry yeast US05, S-04,Nottingham ext.
  4. premierpro

    premierpro Savant (385) Michigan Mar 21, 2009

    The longest I have kept yeast was 3 months. I pitched without a starter. It had a 2 day lag then did it's job. I am not sure I would hold yeast any longer.
  5. Hands22

    Hands22 Savant (265) Florida Oct 14, 2011

    White and Jamil's book, Yeast, has a really good write up on yeast handling. They suggest a (pro) brewer can use 8-10 generations of ale yeast and 4-5 of lager, assuming proper sanitation and collecting. Vitality and viability of the yeast is harder to gauge... The best way is to keep notes of how each generation of the strain acts and keep that in mind for future harvesting.

    I can't comment much on time as I haven't stored yeast for longer than a week. I've been looking into adding glycerol and freezing for long term storage but haven't tried it yet.
  6. Hands22

    Hands22 Savant (265) Florida Oct 14, 2011

    Actually, I just found the table I was looking for in White's book. For harvested slurry at 38F, he says the reliable shelf life is 2 weeks and the max shelf life is 6 months. The reason for the short reliable shelf life is based on "maintaining a mutation-free culture".
  7. mnstorm99

    mnstorm99 Advocate (535) Minnesota May 11, 2007

    Have you had luck repitching harvested dry yeast? There is a belief out there that dry yeast does not work well to re-use, mostly based off of the idea of dead cells being left in the yeast cake.

    Personally I have wondered, especially since dry yeast isn't cheap anymore. But, I do still use it sometimes.

    What are some experiences here?
  8. Ilanko

    Ilanko Savant (255) New York Aug 3, 2012

    I have harvested all most every carboy (i like the look of it on the fridge), but every time I split my boil in to 6 gallon carboy and 1 gallon carboy. the first (6 G) get a fresh pack of dry yeast and the second with harvested yeast.
    My approach is not to risking the all batch of 5 gallon, at the same time testing how harvested yeast works. So far i did it up to 4 generation (re-using the same yeast) and i the result are good. The visual fermentation start almost at the same time.
  9. telejunkie

    telejunkie Savant (425) Vermont Sep 14, 2007

    i'll usually crop from krausen on day 2 of active fermentation from nottingham, munich & us05 with good results. I try my best to avoid yeast cake but have used it before when us05 hasn't produced a good krausen. The general stigma is that dry yeast isn't as pure as liquid cultures and therefore more likely to get impurities to start to really express themselves in the beer over successive generations. Personally haven't had issues but I don't think i've used back to back cakes from a dry yeast strain.

    To the OP, i'm forgetting now, but i've reused yeast several months old utilizing a starter to get it going. I usually try to reuse yeast cropped from a fresh batch within a week or so...but think i've gone two weeks before with slow starts but okay results in the end. A starter is your fail safe though.
  10. mnstorm99

    mnstorm99 Advocate (535) Minnesota May 11, 2007

    I like the idea of top cropping, but have yet to do it...I generally just wash the cake.
  11. ororke5000

    ororke5000 Aficionado (130) Ohio Dec 16, 2008

    have successfully made starters and then fermented with yeast that has been in cold storage for over a year. maybe im lucky.
  12. Ilanko

    Ilanko Savant (255) New York Aug 3, 2012

    Do you scoop it from a bucket fermenter ?
    Any way at the point i will be a little worried putting my "hands" in to the fermenter.
  13. mnstorm99

    mnstorm99 Advocate (535) Minnesota May 11, 2007

    Just make sure your scoop is well sanitized, as well as the vessel you put the yeast in.