Harvesting Yeast

Discussion in 'Beginners Brewing Forum' started by west1m, Aug 24, 2019.

  1. west1m

    west1m Active Member

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    OK, so I saw a couple YouTube videos on harvesting yeast, seems simple enough. I have a couple of kegs in the cooler now and a Pilsner going in the fridge. When it's done I was thinking of trying the harvest yeast idea. My question, it might be a while before I can start a new batch, how long will the harvested yeast last in the fridge?
     
  2. J A

    J A Well-Known Member

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    Don't bother harvesting from a keg. Harvest from primary fermentation vessel. Healthy yeast will last a long time but the ratio of live cells drops dramatically over time. Use a yeast calculator that factors for harvest date to estimate cell count so you can figure out how much of your slurry to pitch. After about 6 months, there's a lot of dead cells and depending on what you're brewing and what your yeast strain is, you may prefer making a starter from it. Ales are more forgiving than lagers but I'm confident of maximum cell count up to about a month in the fridge. After that, I assume around 20 percent drop in vitality per month (and so would have to use more and more of the same slurry).
     
  3. philjohnwilliams

    philjohnwilliams Well-Known Member

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    I have used yeast slurry that was 6+ months old, if it is more than a few weeks old I will make a starter using a pitch calculator like JA suggests above.
     
  4. west1m

    west1m Active Member

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    My bad, I was not planning to harvest from keg, only from the Pilsner in the fermenter. That was just to say it could be a while before I would brew up another batch. Good to hear the yeast would last a month or two.
     
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  5. J A

    J A Well-Known Member

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    Lager yeast slurry can be a little problematic. You need a very high cell count for low-temp fermentation. Slurry that's been harvested after lagering in the primary is already potentially many weeks past it's prime. If I'm scheduling to make the best use of the slurry, I'll brew a 5 gallon batch with a double pitch of new yeast (I use dry packets a lot), ferment at the high end of the range and rack the beer off the slurry pretty quickly. As long as I'm using it within a week or maybe two, I can count on a very adequate cell count for at least a 10 gallon batch of a lager. After 3-4 months, it'll still be adequate for another 5 gallon batch but not 10.
    I'm pretty cautious with cell count estimates because I want a really big pitch for quick, strong fermentation at lower temps.
     
  6. Hawkbox

    Hawkbox Well-Known Member

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    I'd say grab some in a mason jar and put it in the fridge, then build a good starter the next time you use it. Or use it quickly.

    Ale yeast is a little more "durable" than lager yeast near as I can tell but either way you'll probably be fine. I have yeast that is months old in my fridge.

    I don't usually harvest though, I build a big ass starter, and then I save about 25% of it in a jar for the next batch and use the rest for the beer. It's a lot easier to manage that way, plus less hops and shit in your yeast. Not a big deal, but I just like doing that. Really though a 500ml mason jar of yeast slurry is going to be a ton of yeast.
     
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  7. west1m

    west1m Active Member

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    Grabbing it from a fresh starter does sound like the way to go. I will kind of have a full cooler when this Pilsner finishes up so it might be a month or so before I start another. I just thought I would save the yeast for another go at it.
     
  8. Hawkbox

    Hawkbox Well-Known Member

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    It's not a bad idea, I've saved a lot of money on yeast.
     
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  9. Trialben

    Trialben Well-Known Member

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    Up untill the poor attenuation last batch I've been using the same ale yeast since Christmas :).
     
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  10. Craigerrr

    Craigerrr Well-Known Member

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    Harvesting from carboys is a bit of an ordeal. I would like to start building up yeast from a starter. I have read that you shouldn't make a starter from dry yeast packets, could I though if I rehydrate it first? I have several packages of US-05 that would like to start a bank with.
     
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  11. Trialben

    Trialben Well-Known Member

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    I do but most things I do in brewing arnt best practice. I overbuild a starter grab some in a cleaned jar and pitch what's left. Then next batch make a starter out of yeast caught in that jar rinse repeat.

    Oh and lately I overbuild my brew by two litres and pinch this due in the boil either into my flask or a growler and use this for starter wort. It means hops in starter and gravity is variant upon boil gravity of batch.
     
  12. Hawkbox

    Hawkbox Well-Known Member

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    It's not necessary but won't hurt anything I believe is the current "Science!". I do it with 34/70 so I have some extra for next time.
     
  13. Brewer #219634

    Brewer #219634 New Member

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    I harvest yeast from the primary fermenter two to three weeks after pitching. I have done this mostly with dry yeasts. I put the slurry in the fridge and on brew day I will add about a pint of water to the slurry and shake it up about twenty minutes before I intend to pitch.
    I will pitch/decant about two thirds of the diluted slurry and discard the rest. The sooner you use the refrigerated slurry, the more viable it will be. It works every time for me.
     
  14. Brewer #219634

    Brewer #219634 New Member

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    I wouldn't try to use harvested yeast over one month old. It could work, but I personally would not take the chance.
     
  15. Hawkbox

    Hawkbox Well-Known Member

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    I've got yeast from February fermenting away right now.
     
  16. west1m

    west1m Active Member

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    Well I gave it a try. The Czech Pilsner had been in the fridge for a couple weeks so I moved it to a fresh Big mouth . Then I added about 3 liters of boiled & cooled water to the first big mouth , gave it a swirl and poured it all into two sanitized 1 gallon pitchers. after settling a while I pulled off the liquid off one of the pitchers and saved three 8 Ounce jars that all look like the right stuff. Didn't need the left over in the other pitcher. I' ll see how this works out if the Pilsner is worth making twice...
     
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  17. Mase

    Mase Well-Known Member

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    Success! [so far]. Based on your description, and as long as you followed proper sanitation procedures, I’m sure the yeasties (where’s @jeffpn ), will do a great job in the next brew.

    And please follow up to let us know how it works out after the next brew.
     
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  18. BOB357

    BOB357 Well-Known Member

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    Most of my beers are brewed with dry yeast starters. Not sure it's necessary, but I use about 100ml of the starter water to rehydrate the yeast before adding to the boiled and cooled starter wort. I'm actually getting consistently faster starts and shorter fermentation times than I got using liquid yeasts in starters. My beers have been turning out great too.
     
  19. Please Delete!

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    Ok so i was reading thru this thread as I am noticing the cost of yeast.
    And i am thinking it would be easier to do a large starter and split it to 2-3 mason jars.
    My question is how big a starter should I do? I have a 2 liter flask but could come up with something bigger if necessary
     
  20. Trialben

    Trialben Well-Known Member

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    It'd depend on how many jars you want to collect off of it. 2lt should be good but you'd need to step your mason jars yeast count up again before use for a more adequate cell count.

    I make a 2.5 it starter pinch 500ml into jar and pitch the rest.
     
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