Author Topic: Let's Discuss Dry Yeast  (Read 10044 times)

Offline Bel Air Brewing

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Re: Let's Discuss Dry Yeast
« Reply #195 on: December 07, 2021, 10:53:25 am »

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

Very likely

That is my suspicion. But each generation continues to perform well, and the resulting beer is always good.
I wonder how long we can continue with this procedure, before we have to dump the yeast and start over?
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Offline tommymorris

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Let's Discuss Dry Yeast
« Reply #196 on: December 07, 2021, 11:01:58 am »
Are there ways professional breweries purify their slurries; every batch or periodically? I thought I have read about acids that can be used to kill contaminate, but allow the yeast to survive. Maybe I’m crazy.

Mark mentioned that Anchor never goes back to the source yeast.

Offline erockrph

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Re: Let's Discuss Dry Yeast
« Reply #197 on: December 07, 2021, 11:50:10 am »

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

Very likely

That is my suspicion. But each generation continues to perform well, and the resulting beer is always good.
I wonder how long we can continue with this procedure, before we have to dump the yeast and start over?

Short answer - as long as the culture tastes and performs as well as you like it.

Longer answer - there are two separate issues, contamination and genetic drift. As far as contamination goes, as long as your yeast is outcompeting the other microbes that come along at pitching, you probably won't notice a significant flavor contribution from the other microbes. With genetic drift, over time you may notice that the culture become more or less flocculant or attenuative as you select for certain cells based on how you collect them. If your beers become too dry, less attenuated, or develop some off flavors, then it may be time to start over with a fresh culture.
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Offline ynotbrusum

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Re: Let's Discuss Dry Yeast
« Reply #198 on: December 07, 2021, 11:56:33 am »

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

Very likely

That is my suspicion. But each generation continues to perform well, and the resulting beer is always good.
I wonder how long we can continue with this procedure, before we have to dump the yeast and start over?

The furthest I went with successive re-pitching was 25 total pitches, using an American Lager yeast, over the course of about 2 years.  I experienced no problems and simply wanted to change to another yeast.  It was as robust as when I started in terms of fermentation time and attenuation.  Could there have been fall off in some measurable way?  Perhaps, but no one complained about the beers made with it.  I rarely go beyond 6-9 pitches anymore and sometimes just one or two - the dry lager yeasts are good enough and cheap enough that I don't sweat it.

I recall hearing of homebrewers who used the water purification tablets to wash yeast for re-building and re-use, but I have never seen the need.
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Offline Bel Air Brewing

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Re: Let's Discuss Dry Yeast
« Reply #199 on: December 07, 2021, 11:57:46 am »

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

Very likely

That is my suspicion. But each generation continues to perform well, and the resulting beer is always good.
I wonder how long we can continue with this procedure, before we have to dump the yeast and start over?

Short answer - as long as the culture tastes and performs as well as you like it.

Longer answer - there are two separate issues, contamination and genetic drift. As far as contamination goes, as long as your yeast is outcompeting the other microbes that come along at pitching, you probably won't notice a significant flavor contribution from the other microbes. With genetic drift, over time you may notice that the culture become more or less flocculant or attenuative as you select for certain cells based on how you collect them. If your beers become too dry, less attenuated, or develop some off flavors, then it may be time to start over with a fresh culture.

Thanks, that is good insight.
We have been lucky so far with pitching multi-gen yeast. I guess we will find out some day when a batch of beer does not meet our standards, due to poorly performing yeast, and then will be dumped...or given to my in laws. Never let a bad beer go to waste!
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Offline Bel Air Brewing

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Re: Let's Discuss Dry Yeast
« Reply #200 on: December 07, 2021, 12:02:08 pm »

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

Very likely

That is my suspicion. But each generation continues to perform well, and the resulting beer is always good.
I wonder how long we can continue with this procedure, before we have to dump the yeast and start over?

The furthest I went with successive re-pitching was 25 total pitches, using an American Lager yeast, over the course of about 2 years.  I experienced no problems and simply wanted to change to another yeast.  It was as robust as when I started in terms of fermentation time and attenuation.  Could there have been fall off in some measurable way?  Perhaps, but no one complained about the beers made with it.  I rarely go beyond 6-9 pitches anymore and sometimes just one or two - the dry lager yeasts are good enough and cheap enough that I don't sweat it.

I recall hearing of homebrewers who used the water purification tablets to wash yeast for re-building and re-use, but I have never seen the need.

Yes, dry yeast (lager /ale) is inexpensive. Well...depends on where you buy it. But the primary reason we harvest, and repitch, is because of the performance of the harvested yeast.

The 2nd, 3rd, etc., generation seems to do better than the previous generation.
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Offline ynotbrusum

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Re: Let's Discuss Dry Yeast
« Reply #201 on: December 07, 2021, 12:05:49 pm »
I agree that those re-pitches often out perform the initial pitch of dry yeast - just remember to aerate well and give nutrient to the re-pitches. (My experience, anyway).
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Re: Let's Discuss Dry Yeast
« Reply #202 on: December 07, 2021, 12:07:07 pm »

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

Very likely

That is my suspicion. But each generation continues to perform well, and the resulting beer is always good.
I wonder how long we can continue with this procedure, before we have to dump the yeast and start over?

How long is a piece of string?  I just pay attention to how the slurry looks, smells and performs to decide.
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Re: Let's Discuss Dry Yeast
« Reply #203 on: December 07, 2021, 12:08:02 pm »
Are there ways professional breweries purify their slurries; every batch or periodically? I thought I have read about acids that can be used to kill contaminate, but allow the yeast to survive. Maybe I’m crazy.

Mark mentioned that Anchor never goes back to the source yeast.

The breweries I've worked with around here did nothing but xfer it from one fermenter to another.
Life begins at 60.....1.060, that is!

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Offline Bel Air Brewing

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Re: Let's Discuss Dry Yeast
« Reply #204 on: December 07, 2021, 04:03:28 pm »
Are there ways professional breweries purify their slurries; every batch or periodically? I thought I have read about acids that can be used to kill contaminate, but allow the yeast to survive. Maybe I’m crazy.

Mark mentioned that Anchor never goes back to the source yeast.

The breweries I've worked with around here did nothing but xfer it from one fermenter to another.

That is the ideal practice. It requires constant brewing, or at least brewing on a regular basis. We have done this previously with very good results.
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Offline dannyjed

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Re: Let's Discuss Dry Yeast
« Reply #205 on: December 08, 2021, 04:20:27 pm »
I repitched both WY 1056 and WY 2206 for twenty generations and I noticed no change in performance. I was trying to see how many times it would take for some sort of genetic drift, but it didn’t happen. Eventually, I wanted to try other yeasts and gave up. Another thing that I remember Mark stating was that actually each fermentation is around 5 generations of yeast replicating itself.


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Offline Bel Air Brewing

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Re: Let's Discuss Dry Yeast
« Reply #206 on: December 09, 2021, 03:34:25 am »
I repitched both WY 1056 and WY 2206 for twenty generations and I noticed no change in performance. I was trying to see how many times it would take for some sort of genetic drift, but it didn’t happen. Eventually, I wanted to try other yeasts and gave up. Another thing that I remember Mark stating was that actually each fermentation is around 5 generations of yeast replicating itself.

That is good to know.
I guess a human analogy would be every 7 to 10 years most, but not all, of our cells are replicated.
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Offline dmtaylor

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Re: Let's Discuss Dry Yeast
« Reply #207 on: February 16, 2022, 06:12:58 am »
I'll be honest with you guys.  I just did my blind tasting of S-189 vs. Diamond, and.... I really just cannot tell these apart.  I thought maybe I could on the first sip, but after that, they really just tasted identical.  If anything, I found S-189 might have had more hop flavor, while Diamond tasted less hoppy but also more bitter... but this was like splitting hairs.  I really don't know if it was just my imagination.  I got the same attenuation and FG with both, so I'm almost thinking maybe... these are super closely related.

Update 3 months later...

What a difference age made.  I tasted the two versions side by side again.  The S-189 was slightly hazy, and a bit fruity, and tasted more "like homebrew" (which I think might be some oxidation), versus the Diamond which was darker and clear, and tasted like a very lovely German lager indeed!  So I've finally got my answer, Diamond is my favorite lager yeast without any doubt!

Granted, if memory serves, these were fermented warm as well, which might have added that slight fruitiness to the S-189, which I do not pick up as much in Diamond.

I've been raving about S-189 for years, and it's a great yeast.  But I'll be playing with Diamond a whole lot more in future.

Cheers.
« Last Edit: February 16, 2022, 06:15:34 am by dmtaylor »
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Offline purduekenn

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Re: Let's Discuss Dry Yeast
« Reply #208 on: February 18, 2022, 07:49:10 am »
What temperature did you ferment at?

Offline narvin

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Re: Let's Discuss Dry Yeast
« Reply #209 on: February 18, 2022, 08:04:08 am »
I had a very sluggish fermentation with Diamond, even with pitching 2 packs in 4 gallons and fermenting at 52-55.  It's finally cleaning up with time but it stunk like old bread and feet (not sulfur) at first.  I'm wondering if the Label Peelers discount yeast is garbage.
« Last Edit: February 18, 2022, 08:06:16 am by narvin »