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General Category => Yeast and Fermentation => Topic started by: Bel Air Brewing on December 02, 2020, 09:51:02 am

Title: Yeast Mutation
Post by: Bel Air Brewing on December 02, 2020, 09:51:02 am
We all know that yeast, like a virus, will mutate over successive generations.

But how long does this take in the real world? How many generations will remain true to the original? Do mutations automatically mean the yeast will no longer perform?

Is there a chance that a mutant yeast would actually improve in character?

How do you know a yeast has mutated to the point of no longer being viable for beer?

My experience has been that each successive generation will actually perform better than the previous generation, up to a point. Is this the result of mutation?
Title: Re: Yeast Mutation
Post by: denny on December 02, 2020, 10:09:25 am
How long is a piece of string?
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 02, 2020, 10:44:03 am
How long is a piece of string?

How long is your string, on average?
Title: Re: Yeast Mutation
Post by: RC on December 02, 2020, 11:05:43 am
How long is a piece of string?

How long is your string, on average?

Yeah too much to unpack here regarding mutation (and genetic drift is arguably a bigger consideration anyway), but a couple of these questions can be fairly easily answered:
----------
How do you know a yeast has mutated to the point of no longer being viable for beer? Unless you want to take up yeast plating and start a microbiology lab in your house, the only way to know is via fermentation performance and flavor profile of a batch using that yeast. EDIT: But also, declining performance/flavor could instead or in addition be due to bacterial and/or wild yeast infection. This is much more likely to be the reason for declining performance/flavor at the homebrew level than mutation. Again, you'd need a lab to distinguish between the two.

My experience has been that each successive generation will actually perform better than the previous generation, up to a point. Is this the result of mutation? No. It is because the cells are fat and happy and healthy because they have been repeatedly and extremely well-fed on the food source they like the most.
Title: Re: Yeast Mutation
Post by: denny on December 02, 2020, 11:21:28 am
How long is a piece of string?

How long is your string, on average?

About this long..... ;D
Title: Re: Yeast Mutation
Post by: denny on December 02, 2020, 11:22:20 am
How long is a piece of string?

How long is your string, on average?

Yeah too much to unpack here regarding mutation (and genetic drift is arguably a bigger consideration anyway), but a couple of these questions can be fairly easily answered:
----------
How do you know a yeast has mutated to the point of no longer being viable for beer? Unless you want to take up yeast plating and start a microbiology lab in your house, the only way to know is via fermentation performance and flavor profile of a batch using that yeast. EDIT: But also, declining performance/flavor could instead or in addition be due to bacterial and/or wild yeast infection. This is much more likely to be the reason for declining performance/flavor at the homebrew level than mutation. Again, you'd need a lab to distinguish between the two.

My experience has been that each successive generation will actually perform better than the previous generation, up to a point. Is this the result of mutation? No. It is because the cells are fat and happy and healthy because they have been repeatedly and extremely well-fed on the food source they like the most.

Love that last paragraph
Title: Yeast Mutation
Post by: BrewBama on December 02, 2020, 11:34:21 am
How long is a piece of string? 

Tommy previously answered this question:


2*pi*r exactly. r depends on the radius of circle the string fits around.

From another post:


I recall a Dr Bamforth interview where he said he was given a lecture in England. He said something like he prefers not going into double digits repitching before a replacement pitch is grown from a master colony. A gentleman in the back stood and said they’re on something like their 4000th+ repitch at last count!



Sent from my iPad using Tapatalk
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 02, 2020, 11:36:50 am
Thanks for the constructive input.
Title: Re: Yeast Mutation
Post by: tommymorris on December 02, 2020, 11:52:29 am
How long is a piece of string?
2*pi*r where r is the radius of the circle you form with the string.
Title: Yeast Mutation
Post by: BrewBama on December 02, 2020, 11:53:25 am
How long is a piece of string?
2*pi*r where r is the radius of the circle you form with the string.
Sorry Brother. I stole your thunder (#7 above).


Sent from my iPad using Tapatalk
Title: Re: Yeast Mutation
Post by: tommymorris on December 02, 2020, 12:43:22 pm
How long is a piece of string?
2*pi*r where r is the radius of the circle you form with the string.
Sorry Brother. I stole your thunder (#7 above).


Sent from my iPad using Tapatalk
Whoops. I forgot I had already used that joke. Party fouls on my part ;)
Title: Re: Yeast Mutation
Post by: ynotbrusum on December 02, 2020, 01:07:34 pm
I have experienced petite mutants arising in a single batch that was stressed in one way or another (typically underpitched, fermentation temperature issues, or similar stressor during fermentation).  Once there, I am not sure how to rid the slurry of the problem mutant presence, though plating and culturing would be one way that comes to mind.

Improvement of the beer by the existence?  I suppose it’s possible if that expression is something sought in the style (4VG, perhaps or clove character in a Hefeweizen)?

Others may have specific stressors that they seek in a style
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 02, 2020, 01:40:25 pm
I have experienced petite mutants arising in a single batch that was stressed in one way or another (typically underpitched, fermentation temperature issues, or similar stressor during fermentation).  Once there, I am not sure how to rid the slurry of the problem mutant presence, though plating and culturing would be one way that comes to mind.

Improvement of the beer by the existence?  I suppose it’s possible if that expression is something sought in the style (4VG, perhaps or clove character in a Hefeweizen)?

Others may have specific stressors that they seek in a style

Thanks. In our case with acute over pitching, might that cause mutation?
Note that my 8th generation of W-34/70 seemed just fine after rousing it with some fresh wort. It is now chugging away in another Euro-Lager.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 02, 2020, 04:01:15 pm
My experience has been that each successive generation will actually perform better than the previous generation, up to a point. Is this the result of mutation? No. It is because the cells are fat and happy and healthy because they have been repeatedly and extremely well-fed on the food source they like the most.

Your observation is absolutely correct. Yeast cultures do in fact improve in performance up to a point.  It is called adaptation. Sadly, that is selective, cropping technique, and yeast genetics dependent.  I am of the firm belief if one serially crops selectively and does not over pitch, what will happen is that yeast cells not well adapted to one's selection criteria will be winnowed out leaving those that perform well in one's brewery. 
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 02, 2020, 04:43:24 pm
My experience has been that each successive generation will actually perform better than the previous generation, up to a point. Is this the result of mutation? No. It is because the cells are fat and happy and healthy because they have been repeatedly and extremely well-fed on the food source they like the most.

Your observation is absolutely correct. Yeast cultures do in fact improve in performance up to a point.  It is called adaptation. Sadly, that is selective, cropping technique, and yeast genetics dependent.  I am of the firm belief if one serially crops selectively and does not over pitch, what will happen is that yeast cells not well adapted to one's selection criteria will be winnowed out leaving those that perform well in one's brewery.

Good info. I am cutting back slightly on pitch rate.
Title: Re: Yeast Mutation
Post by: ynotbrusum on December 02, 2020, 06:39:49 pm
And for what it’s worth, I have taken a lager yeast out 25 repitches with no observed off flavors or performance issues. It took a couple years and I stopped only because I feltI had satisfied myself and wanted to move onto other strains.
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 02, 2020, 07:22:39 pm
And for what it’s worth, I have taken a lager yeast out 25 repitches with no observed off flavors or performance issues. It took a couple years and I stopped only because I felt I had satisfied myself and wanted to move onto other strains.

That's good to know. I've never gone that far, simply due to fear of the unknown. Around 10 generations has been the max for me. But armed with this info, we will continue to re-pitch without being overly concerned.

My yeast has sat for about 5 months, completely dormant. And then re-pitched without any problems. I try to brew faster and re-use the yeast on a more rapid schedule.

The problem arises when you have three, four, or more yeasts in storage.

I have the following, all being harvested:

Kolsch (Wyeast)
London Ale (Wyeast)
Czech Pils (Wyeast)
W-34/70 (Saflager)
Oktoberfest (Wyeast Blend)

The only ones not working right now are the Kolsch and the Czech Pils.

We have 40 gallons fermenting at this time.
Title: Re: Yeast Mutation
Post by: Descardeci on December 03, 2020, 10:03:48 am
And for what it’s worth, I have taken a lager yeast out 25 repitches with no observed off flavors or performance issues. It took a couple years and I stopped only because I felt I had satisfied myself and wanted to move onto other strains.

That's good to know. I've never gone that far, simply due to fear of the unknown. Around 10 generations has been the max for me. But armed with this info, we will continue to re-pitch without being overly concerned.

My yeast has sat for about 5 months, completely dormant. And then re-pitched without any problems. I try to brew faster and re-use the yeast on a more rapid schedule.

The problem arises when you have three, four, or more yeasts in storage.

I have the following, all being harvested:

Kolsch (Wyeast)
London Ale (Wyeast)
Czech Pils (Wyeast)
W-34/70 (Saflager)
Oktoberfest (Wyeast Blend)

The only ones not working right now are the Kolsch and the Czech Pils.

We have 40 gallons fermenting at this time.

Mutation is complex thing, is hard to observe with some organism and easier in others, there artificial and natural selection and genetic drift, those all can enter the count to change the yeast, but I don't think this is really a problem in brewing, you're using a single strain, the mutation can be for a little change of flocculation or attenuation or nothing, but the enviroment you're creating will favor those without mutation, the select strains that the lab sell to you, you're not change too much the enviroment, you're give the same sugars all the time you make beer, same pH, or close, and is not adding another organism to compete with the yeast so mutation can happen but I don't think it will afect your beer, I'm speaking this a biology, but I'm not a expert on yeast mutation or nothing like this, just give my thoughts
Title: Re: Yeast Mutation
Post by: hopfenundmalz on December 03, 2020, 11:12:41 am
How long is a piece of string? 

Tommy previously answered this question:


2*pi*r exactly. r depends on the radius of circle the string fits around.

From another post:


I recall a Dr Bamforth interview where he said he was given a lecture in England. He said something like he prefers not going into double digits repitching before a replacement pitch is grown from a master colony. A gentleman in the back stood and said they’re on something like their 4000th+ repitch at last count!



Sent from my iPad using Tapatalk

Harveys claims to have used the same yeast for 50 years or so.
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 03, 2020, 01:50:04 pm
The same yeast for 50 years? Is the strain always harvested?

Or are there scientists with white lab coats propagating the yeast cells to ensure that the strain remains pure?
Title: Re: Yeast Mutation
Post by: hopfenundmalz on December 03, 2020, 04:34:52 pm
The same yeast for 50 years? Is the strain always harvested?

Or are there scientists with white lab coats propagating the yeast cells to ensure that the strain remains pure?

How about 63 years? I don't know all the answers, but watch the video.

https://www.harveys.org.uk/news/60th-anniversary-harveys-yeast

I have really enjoyed the Harvey's beers that I've had in England.
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 03, 2020, 07:22:27 pm
The same yeast for 50 years? Is the strain always harvested?

Or are there scientists with white lab coats propagating the yeast cells to ensure that the strain remains pure?

How about 63 years? I don't know all the answers, but watch the video.

https://www.harveys.org.uk/news/60th-anniversary-harveys-yeast

I have really enjoyed the Harvey's beers that I've had in England.

Good story, thanks. I'll see if we can go a few hundred generations!
Title: Re: Yeast Mutation
Post by: Northern_Brewer on December 04, 2020, 02:26:10 am
It's complicated, not least because it depends massively on your cropping regime - top-cropping an open fermenter at high krausen and repitching every week as in a traditional British brewery will give much happier yeast than something that's been swilling round the bottom of a conical for weeks.and then left in a fridge for a few months. It also depends on the strain, some are just more "fragile" than others.

General view seems to be that typical bought-in yeast in commercial conicals is good for about 10-12 repitches and then it becomes a bit of a lottery. Apparently the Conan at the Alchemist can be run for 50 generations but after 15 or so it gets into a cycle of "bad" pitches and then "good" ones. I suspect part of what's happening in these old British multistrains (and the Harvey's one is not particularly old by these standards) is that you have different strains cycling at different rates, which gives the appearance of a blend that's fairly robust.
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 04, 2020, 04:52:59 am
We toured the Hoffbrau Brewery last January, in Munich. They re-pitch through the 3rd generation, and then start with fresh virgin yeast. They indicated too many issues with maintaining the same yeast quality and flavor profile is why they don't go beyond 3 generations.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 04, 2020, 05:40:24 pm
We toured the Hoffbrau Brewery last January, in Munich. They re-pitch through the 3rd generation, and then start with fresh virgin yeast. They indicated too many issues with maintaining the same yeast quality and flavor profile is why they don't go beyond 3 generations.

Either they use an unstable yeast strain or they are limiting growth during pitching.  Do they use cylindroconical fermentation vessels?
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 04, 2020, 06:17:45 pm
We toured the Hoffbrau Brewery last January, in Munich. They re-pitch through the 3rd generation, and then start with fresh virgin yeast. They indicated too many issues with maintaining the same yeast quality and flavor profile is why they don't go beyond 3 generations.

Either they use an unstable yeast strain or they are limiting growth during pitching.  Do they use cylindroconical fermentation vessels?

Yes.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 04, 2020, 06:22:19 pm
Thanks. In our case with acute over pitching, might that cause mutation?
Note that my 8th generation of W-34/70 seemed just fine after rousing it with some fresh wort. It is now chugging away in another Euro-Lager.

The problem you are experiencing is due to lack of new cell production resulting in a culture that contains too many old cells. Old cells suffer from mitochondrial DNA damage due to reactive oxygen species (ROS).

All cultures are going to mutate over time.  That is how house cultures come about.  Over time, a culture develops variants due to single nucleotide polymorphisms. Allow these variants to continue to mutate and a pure culture is going to a multi-strain culture.  We have to remember what most brewers refer to as culture generation is actually the serial crop ordinal value.  The number of generations a yeast culture has undergone can be approximated by multiplying the serial crop ordinal value by 4.5.  For example, the approximate number of generations serial crop number 7 has undergone since the culture was initially pitched is 7 * 4.25 = 29.75; therefore, the youngest cells in the crop are approximately 30 generations away from the cells that were pitched into the first batch in the serial crop sequence.  If each generation of humans reproduced at age 20, it would take 600 years to produce 30 generations.  That is why yeast is a good organism for genetic research.

With that said, amateur brewers should be able to repitch bottom-cropped yeast many more times than a commercial brewery due to the less stressful environment a 5 or 10-gallon fermentation places on a yeast culture.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 04, 2020, 06:24:21 pm
Either they use an unstable yeast strain or they are limiting growth during pitching.  Do they use cylindroconical fermentation vessels?

Yes.

Do you know the volume of these fermentation vessels in hectoliters?
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 04, 2020, 07:53:50 pm
Either they use an unstable yeast strain or they are limiting growth during pitching.  Do they use cylindroconical fermentation vessels?

Yes.

Do you know the volume of these fermentation vessels in hectoliters?

Very large. Not sure about the size. Perhaps two or more stories in height.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 05, 2020, 06:47:58 am
Do you know the volume of these fermentation vessels in hectoliters?

Very large. Not sure about the size. Perhaps two or more stories in height.

That is a lot of hydrostatic pressure.  That is the problem with tall, cylindroconical fermentation vessels.  They place significant hydrostatic pressure on what is in the cone.  People who dive experience hydrostatic pressure.  If one examines the breweries known for repitching, volume is increased not by growing fermentation vessels up, but by growing them outward.
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 05, 2020, 09:11:39 am
Do you know the volume of these fermentation vessels in hectoliters?

Very large. Not sure about the size. Perhaps two or more stories in height.

That is a lot of hydrostatic pressure.  That is the problem with tall, cylindroconical fermentation vessels.  They place significant hydrostatic pressure on what is in the cone.  People who dive experience hydrostatic pressure.  If one examines the breweries known for repitching, volume is increased not by growing fermentation vessels up, but by growing them outward.

So as home brewers we are causing issues with tall conical type ferment vessels?
I have seen large, flat, shallow, open air ferment tanks in a few breweries in the Old World.
Title: Re: Yeast Mutation
Post by: denny on December 05, 2020, 10:06:25 am
Do you know the volume of these fermentation vessels in hectoliters?

Very large. Not sure about the size. Perhaps two or more stories in height.

That is a lot of hydrostatic pressure.  That is the problem with tall, cylindroconical fermentation vessels.  They place significant hydrostatic pressure on what is in the cone.  People who dive experience hydrostatic pressure.  If one examines the breweries known for repitching, volume is increased not by growing fermentation vessels up, but by growing them outward.

So as home brewers we are causing issues with tall conical type ferment vessels?
I have seen large, flat, shallow, open air ferment tanks in a few breweries in the Old World.

No, because ours are smaller volume.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 06, 2020, 10:45:27 am
That is a lot of hydrostatic pressure.  That is the problem with tall, cylindroconical fermentation vessels.  They place significant hydrostatic pressure on what is in the cone.  People who dive experience hydrostatic pressure.  If one examines the breweries known for repitching, volume is increased not by growing fermentation vessels up, but by growing them outward.

So as home brewers we are causing issues with tall conical type ferment vessels?
I have seen large, flat, shallow, open air ferment tanks in a few breweries in the Old World.

As Denny mentioned, our volumes are not large enough to exert much in the way of hydrostatic pressure.  If temperature is maintained, the average amateur brewers places little in the way of environment stress on a yeast culture, which is why we should be able to serially repitch bottom-cropped yeast if care is made to ensure that average cell age remains young.  The major problem with bottom-cropped yeast is wild microflora ingress.  Top-cropped yeast is much cleaner in terms of wild microflora because wild microflora does not floc to the top. However, few brewing cultures are true top-croppers these days due to the extensive use of cylindroconical fermentation vessels and I have yet to see a Sacharomyces pastorianus culture floc to the top. 

That being said, I am currently reading "Lager" by Dave Carpenter.  The book is beautifully put together, but sadly, it has erroneous information with respect to top-cropping.  The author states that top-cropping involves harvesting yeast from krausen and that the practice leads yeast that has lost its ability to flocculate, which is about as incorrect as one can get.   First off, the rocky brown head that forms first is skimmed.  There is very little in the way of re-usable yeast in the brown head.  However, the second head that forms it almost pure yeast that has flocculated. A lot of brewers conflate flocculation with sedimentation.  Even non-flocculent yeast strains will eventually sediment if given enough time.  Flocculation is the aggregation of yeast cells into flocs.  Most brewing cultures fall into the NewFlo flocculation phenotype.   Flocculaton occurs in NewFlo cultures after the sugars mannose, glucose, sucrose, maltose, and all of the polysaccharides that can be reduced to one of these sugars have been exhausted, which is why spinning a yeast culture to keep it in suspension demonstrates a fundamental lack of understanding of brewing yeast culture biology.  Flocculation is inhibited as long as mannose is in solution because mannose binds to the protein-saccharide receptor that is involved in flocculation.  We can think of this receptor as the yeast cell wall equivalent of Velcro. What differentiates true top-cropping brewing cultures from the rest is that they entrap CO2 gas when they floc, which is which why they rise to the surface.  What keeps a top-cropped culture from becoming powdery (non-flocculent) is the practice of taking the middle head.  If we discarded the middle head and kept the last head, our culture would become progressively more powdery.
Title: Re: Yeast Mutation
Post by: Qzm on December 14, 2020, 08:30:01 am
As Denny mentioned, our volumes are not large enough to exert much in the way of hydrostatic pressure.
To put it another way:

If you take a typical homebrew in a conical fermenter and measure the absolute bottom-most molecule, you will find it has ~21kg* sitting on top of it.

Take the equivalent molecule from 1000l conical of the same batch, and it has more than* a literal tonne weighing down on it (and that much fits in roughly a cubic yard, for visualisation).

There's more complexity to it, certainly, but for the purpose of getting the idea into even the drunkest homebrewer's head... it's enough to use the imagery of carrying a sack of grain versus carrying a car. That should be enough to grasp that the home and commercial situations are subtly different :P.

*Twenty liters multiplied by a specific gravity of 1.06.
Title: Re: Yeast Mutation
Post by: hopfenundmalz on December 14, 2020, 05:57:53 pm
As Denny mentioned, our volumes are not large enough to exert much in the way of hydrostatic pressure.
To put it another way:

If you take a typical homebrew in a conical fermenter and measure the absolute bottom-most molecule, you will find it has ~21kg* sitting on top of it.

Take the equivalent molecule from 1000l conical of the same batch, and it has more than* a literal tonne weighing down on it (and that much fits in roughly a cubic yard, for visualisation).

There's more complexity to it, certainly, but for the purpose of getting the idea into even the drunkest homebrewer's head... it's enough to use the imagery of carrying a sack of grain versus carrying a car. That should be enough to grasp that the home and commercial situations are subtly different :P.

*Twenty liters multiplied by a specific gravity of 1.06.

Volume doesn't factor in to hydrostatic pressure.

https://www.engineeringtoolbox.com/hydrostatic-pressure-water-d_1632.html
Title: Re: Yeast Mutation
Post by: Qzm on December 14, 2020, 07:27:58 pm
Volume doesn't factor in to hydrostatic pressure.

https://www.engineeringtoolbox.com/hydrostatic-pressure-water-d_1632.html
I've not studied fluid mechanics in the slightest, but my understanding was that mass is what we'd be most concerned with here (given that we can't do much about gravitational acceleration, and we're buying off-the-shelf conical designs :P). Pressure may be the relevant unit of measurement regarding the cells, but expressing it as weight is not exactly wrong*, though the conceptualisation I presented is obviously a gross simplification and explicitly specific to a theoretical lowest, narrowest possible point (higher points will have lower pressures/less force being applied).

The thrust of my post was to illustrate why people don't have to worry about it in homebrewing, rather than to elaborate how it works.

*Though one should really give weight by area, in order for it to actually be convertible.

EDIT: And I am assuming we're brewing in incompressible fluids. If not, I'd love to see a vlog on the process :D.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 18, 2020, 05:17:59 am

Volume doesn't factor in to hydrostatic pressure.

https://www.engineeringtoolbox.com/hydrostatic-pressure-water-d_1632.html

However, fermentation vessel volume does play a role in hydrostatic pressure due to the fact that breweries tend to want to maximize floor space, which means growing fermentation vessels up instead of out.  Let's compare 5.22 gallons of wort in a 6-gallon plastic carboy versus 5.22 gallons in a 2" diameter, 32' high cylindrical fermentation vessel (3.14 * 1 * 1 * 32 * 12 / 231 = ~5.22 gallons).  The yeast cake on the bottom of the plastic plastic carboy experiences less than 1.42 psi of hyrdrostatic pressure whereas the yeast cake at the bottom of the 2" diameter fermentation vessel experiences over 42.7 psi of hydrostatic pressure.  The moral of the story is that if one has space, it is better to grow fermentation vessels out than up.  That recommendation not only applies to hydrostatic pressure, but also to heat dissipation and O2 pickup. Let's look at Anchor.  Anchor open ferments in what are basically coolships for the very reason that wort used to be cooled in coolships; namely, the high surface area to volume ratio afforded the original Anchor brewers better heat dissipation than other fermentation vessel designs during a period of time when mechanical refrigeration was a luxury.  Today, that style of fermentation is part of the flavor profile.
Title: Re: Yeast Mutation
Post by: Cliffs on December 18, 2020, 09:45:26 am
unfortunately Anchor Steam doesnt seem too preoccupied with how their beer tastes these days. I live somewhat close to the brewery and can get fresh examples and it has declined greatly in the last few years.
Title: Re: Yeast Mutation
Post by: Saccharomyces on December 19, 2020, 06:09:25 am
unfortunately Anchor Steam doesnt seem too preoccupied with how their beer tastes these days. I live somewhat close to the brewery and can get fresh examples and it has declined greatly in the last few years.

I was wondering what the Sapporo purchase of Anchor would do to the beer.
Title: Re: Yeast Mutation
Post by: Bel Air Brewing on December 19, 2020, 07:03:08 am
unfortunately Anchor Steam doesnt seem too preoccupied with how their beer tastes these days. I live somewhat close to the brewery and can get fresh examples and it has declined greatly in the last few years.

I was wondering what the Sapporo purchase of Anchor would do to the beer.

Let's hope the result is not the same as when Miller purchased the Celis Brewery, in Austin, Texas. Celis brewed wonderful Belgian beers. But after the purchase was made, the brewery was scuttled.

Recently, the original owners somehow obtained the rights to the building, and started the brewery up again, but it is a shadow of what it used to be.

As I do not consume wheat beers, I was not a fan. No idea what yeast they use, or if the yeast tends to mutate in their brewery.

https://www.celisbeers.com/
Title: Re: Yeast Mutation
Post by: hopfenundmalz on December 19, 2020, 08:54:22 am

Volume doesn't factor in to hydrostatic pressure.

https://www.engineeringtoolbox.com/hydrostatic-pressure-water-d_1632.html

However, fermentation vessel volume does play a role in hydrostatic pressure due to the fact that breweries tend to want to maximize floor space, which means growing fermentation vessels up instead of out.  Let's compare 5.22 gallons of wort in a 6-gallon plastic carboy versus 5.22 gallons in a 2" diameter, 32' high cylindrical fermentation vessel (3.14 * 1 * 1 * 32 * 12 / 231 = ~5.22 gallons).  The yeast cake on the bottom of the plastic plastic carboy experiences less than 1.42 psi of hyrdrostatic pressure whereas the yeast cake at the bottom of the 2" diameter fermentation vessel experiences over 42.7 psi of hydrostatic pressure.  The moral of the story is that if one has space, it is better to grow fermentation vessels out than up.  That recommendation not only applies to hydrostatic pressure, but also to heat dissipation and O2 pickup. Let's look at Anchor.  Anchor open ferments in what are basically coolships for the very reason that wort used to be cooled in coolships; namely, the high surface area to volume ratio afforded the original Anchor brewers better heat dissipation than other fermentation vessel designs during a period of time when mechanical refrigeration was a luxury.  Today, that style of fermentation is part of the flavor profile.

It is still specific gravity times acceleration of gravity times height that determines the pressure. I get your point on vessel geometry. There is also the square vs round designs, the round ones are used for Weißbier in Germany, I've seen many square ones for lagers.

Title: Re: Yeast Mutation
Post by: Saccharomyces on December 19, 2020, 09:07:21 am
It is still specific gravity times acceleration of gravity times height that determines the pressure. I get your point on vessel geometry. There is also the square vs round designs, the round ones are used for Weißbier in Germany, I've seen many square ones for lagers.

Yes, it is still a specific gravity times acceleration of gravity times height problem.  However, the takeaway here is that the volumes of wort amateur brewers make are too small to have to make the height versus width trade off that designers of commercial breweries have to make.  Any commonly used fermentation vessel at the amateur brewing level is not going to place much in the way of hydrostatic pressure on fermenting beer. Hydrostatic pressure does have an upside; namely, reduction in ester production.
Title: Re: Yeast Mutation
Post by: ynotbrusum on December 21, 2020, 05:06:10 am
Brewing under pressure has many advocates.  I wonder about yeast pitches and repitches at say, 12 or 15 psi - how well the yeast holds up....