Do yeast strains change over time?

Discussion in 'Beginners Brewing Forum' started by coreyman, Dec 17, 2019.

  1. coreyman

    coreyman Member

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    So I'm about to pitch with the same WLP004 I've been recycling for about 4-5 months now and I'm wondering if and when there could be genetic mutations introduced?
     
  2. Nosybear

    Nosybear Well-Known Member

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    Absolute answer, it had mutations when you pitched it. Practical answer, unless you're the champion of sanitation, you probably should have changed out by now. Here's the important question: Did it make good beer the last batch? If so, you're probably good.
     
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  3. coreyman

    coreyman Member

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    It made good beer last batch. I like to think I'm pretty good at sanitation. I've never had an infected brew... knock on wood. Are you suggesting my yeast is becoming more infected each time with bacteria due to inefficiencies in the sanitation process?
     
  4. BOB357

    BOB357 Well-Known Member

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    Please delete
     
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  5. BOB357

    BOB357 Well-Known Member

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    Depending on the conditions a yeast is subjected to and how/when it's harvested. it will undoubtedly change. That's a major contributor to the evolution of a strain. I believe that's called selective breeding. At some point there will be mutations and/or other changes. This is why selected pure strains are kept in storage in order to maintain the traits that have been developed over time.

    How many generations before any noticeable changes occur may vary due to many factors. As long as the strain continues to produce characteristic results, I see no problem with reuse.
     
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  6. Nosybear

    Nosybear Well-Known Member

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    Bacterial populations accumulate, mutations accumulate.... That much is inevitable. No, the sanitation question was to get you thinking about how clean the yeast still is. Other side, there have been stable yeast strains for long periods of time, even stable cultures for centuries. Without a good microscope it's hard to tell but as long as the beer comes out good, the culture probably is as well.
     
  7. Trialben

    Trialben Well-Known Member

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    I remember a podcast on that bloke who brews heady topper in the interview he goes about 6 generations with Conan until He ditches it and starts again with a fresh strain. He also said the yeast performs better after a generation or two.

    Poor Attenuation for me is an indicator to throw out my yeast strain.

    Oh and last one if in doubt throw it out and get an fresh pitch.
     
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  8. coreyman

    coreyman Member

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    What % Attenuation do you look for? I always look for close to 90 something % converted because most of my brews do not have high amounts of alcohol in the teens.
     
  9. Trialben

    Trialben Well-Known Member

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    Well let's say you've been consistently hitting at or around 80% attenuation and all of a sudden you get low 70's through no fault of your own like adding high proportions of crystal or mashing high- then this could be an indicator that your yeast maybe performing poorly and time to refresh your yeast strain.
     
  10. coreyman

    coreyman Member

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    Great observation! I'll keep that in mind.
     
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  11. Trialben

    Trialben Well-Known Member

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    Either that or you strike infection is another good indication lol:p.
     
  12. Hawkbox

    Hawkbox Well-Known Member

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    I use it until I get bored and then don't overbuild a starter, or until I realize I have 12+ strains in my fridge and I only use 3 of them.
     
  13. Mase

    Mase Well-Known Member

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    By the skin of my teeth a avoided falling into that black hole. Kudos to those who do that, I just don’t have that drive.
     
  14. Trialben

    Trialben Well-Known Member

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    Know you with your rigerous cleaning regime you'd be able to wing it for sure for a few yeast generations.

    But for sure it can be the cause of dumpers if you screw up on your starters.
     
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  15. Mase

    Mase Well-Known Member

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    It’s crossed my mind a few times when we brew a similar style back to back with the same yeast, by transferring to keg, then adding a batch of wort onto the yeast/trub to see how it would do, but I’ve always held back as Pitching dosage always held me back.
     
  16. BOB357

    BOB357 Well-Known Member

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    Yea, that would be a big over pitch for sure. I usually plan back to back batches that use the same yeast. After transferring to aa keg, I swirl up the dregs and fill a 12 oz. jar, loosely cap and put it in my yeast fridge. More often than not it's pitched within a day or 2. I usually just go for 2 or 3 batches from a pitch.
     
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  17. Mase

    Mase Well-Known Member

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    I just hate seeing all that yeast go down the drain... guilt may overtake reluctance at some point. But I like your approach Bob... but isn’t 12 oz an over pitch as well (assuming an OG around 1.050-ish?
     
  18. BOB357

    BOB357 Well-Known Member

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    A lot less of an over pitch than transferring onto a whole yeast cake. Once it settles out I kind of eyeball it and may not pitch it all. There can be quite a lot of difference in the amount of settled yeast/trub depending on how much beer you swirled it up with in the fermenter.

    My results have been nothing but positive. I really think overpitching is more detrimental to the next generation of the yeast than to the beer unless it's massive. You're pitching plenty of viable yeast and not subjecting it to multiple exposures to possible contamination.

    It's about the easiest and safest yeast handling strategy I've found. You can harvest more than one jar if you wish.
     
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  19. Mase

    Mase Well-Known Member

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    Not to mention coughing up nearly $10 per brew for a pack of liquid yeast. I know, I know, I could use dry yeast and save a few bucks, but I’m a creature of habit and follow the “if it ain’t broke, don’t fix it” belief. We’ve brewed approx 50 brews since January of 2017, and have brewed with the same equipment and approach for 45 of them. But being recently retired, it only makes sense to find economy without compromise, and harvesting yeast is a great place to start. I’ve got all the confidence to harvest/reuse, just haven’t pulled the trigger yet for reasons already discussed above. Now to find an alternative to expensive Deer Park bottled spring water for brewing ($12 bucks for a 5 gallon batch yield), and $10 bucks for two large bags of ice for wort chilling.
     
  20. BOB357

    BOB357 Well-Known Member

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    I know there's somewhere near that you can get RO water. That and some Calcium Chloride and Gypsum will save you quite a bit. At 10 bucks a batch for ice you could buy a good wort chiller and pay for it in savings in no time. I've become very price conscious since retiring too. Just a fact of life you need to get used to.
     
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