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Squatchy

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I just found this a little bit ago and haven't read too much yet. A few of my friends here came to mind. So I thought I would post it to see if you guys wanted to toss some things around after we have all had a chance to digest it. Stasis, maybe this is one of those pieces you think should go on the Patrons side? I sent Vicky a note to see what her thought were about keeping some things on the "patrons section" verses posting them to the open public. I never did ever get a response from her.

Any way. I won't tell you guys what I am anticipating from this read. That way maybe you will see some things I don't.

Here's the link. https://pdfs.semanticscholar.org/d3a2/55ef82822585d7c534a1ca0f4fd8e32c756c.pdf

Why don't you sound off if your up for the challenge.
 

Dadux

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I started reading with interest but i was dissapointed (mead wise, actually i enjoyed the read since I'm interested in the ageing process). The problem is not that much the fact that its old, but the fact that in our case its hard to see the relevance this study has.
The main reason for this is that they measure lifespan in a replicative context, that is, the cell can replicate X times before dying, but that approach offers little information for our case, or so i believe. Let me explain it further:

The mean replications of a yeast cell is around 25 times. This study assumes that after the first 40% of those 25 replications (10 or so, Figure 5) the "lifespan" of the daughter cells is diminished ("lifespan" meaning the ammount of times it manages to replicate). IF you had 2 grams of yeast per gal, after 10 replications (when we start to see a decay of any kind) you'd have 1kg of yeast. I just cant see how this is relevant for our case.
Im not disregarding the study completely, but how the evaluate the case is for us irrelevant.
Another reason for this is the medium they use. They are using YPD medium to grow the yeast. This medium has been seen to extend the lifespan of the cells, because its super rich in nutrients and this also makes them reproduce constantly.

This does not correlate with mead, where you have a somewhat hostile enviroment, with a set ammount of nutrtients, where the lag phase is only a few hours/days at best. The rest is stationary phase, when the yeast is mainly not replicating. So what do i get if they measure the "lifespan" in replications, when after a couple of days my yeast wont be replicating, but accumulating sugars? It does not give me relevant information. Maybe their information has some impact, yes, but we cant know since the place where the cells grow and how they live its completely different. Maybe those last newborn cells in the log phase survive less in the stationary phase, but it'd be hard to tell,

In case you want an overview on how much yeast live in the stationary phase, read this http://onlinelibrary.wiley.com/doi/10.1046/j.1474-9728.2003.00033.x/pdf
(which is not totally accurate because there, the yeast are not in anaerobic conditions and the water is not filled with honey/ethanol, but it gives more insight)

Edit: You could say the most interest this could have is for wild fermented meads where you start with a very low population of yeast that increases very slowly over a long period of time and replicates a lot of times
 
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Stasis

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I just found this a little bit ago and haven't read too much yet. A few of my friends here came to mind. So I thought I would post it to see if you guys wanted to toss some things around after we have all had a chance to digest it. Stasis, maybe this is one of those pieces you think should go on the Patrons side? I sent Vicky a note to see what her thought were about keeping some things on the "patrons section" verses posting them to the open public. I never did ever get a response from her.

Any way. I won't tell you guys what I am anticipating from this read. That way maybe you will see some things I don't.

Here's the link. https://pdfs.semanticscholar.org/d3a2/55ef82822585d7c534a1ca0f4fd8e32c756c.pdf

Why don't you sound off if your up for the challenge.

This could definitely be in the patrons section. There are studies which calculate how complex something can be before a person is put off. In a book the limit of words a reader cannot know per page, in gaming how complex the rules are before a person can start playing, in questionnaires how long questions can be (they limit the long questions and put them towards the end because at least then you know you're soon ready):
So by the same logic I think that while it would be super cool for new members to have access to all the information, it might actually work against us mazers because we might be deterring new mazers. This thread will get buried eventually so nothing wrong done, but if it ends up being a super informative thread I'd hate to pin it in a non-patrons section. While saying this I'm also shooting myself in the foot because I won't be able to stop paying my subscription if I want to be super updated (although progress is kinda slow so if I really wanted to skip some time I could...)
This is just my opinion and it's also biased because I'm trying to defend having patrons at all. Who knows how things work in reality.

About this article, I'm with Dadux. Very well said. Although I calculated 2kgs of yeast by 10th replication :p (don't count the 2) 4 - 8 - 16 -32 - 64 -128 -256 - 512 - 1024 - 2048grams
 

Dadux

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About this article, I'm with Dadux. Very well said. Although I calculated 2kgs of yeast by 10th replication :p (don't count the 2) 4 - 8 - 16 -32 - 64 -128 -256 - 512 - 1024 - 2048grams

Haaah i just inputted 2^10 in the calculator. Too lazy ;D , thanks for the correction

Edit: even if I'm not a patron (yet) i have mixed feelings like you guys, but maybe for different reasons.
I dont think you should pay for knowledge. I am totally against the concept, and that is how i see it. So on that side I think the thread is fine on the "commoners" section ;D
But on the other hand the website does not maintain itself and the fee is not too high. So if noone has no reason to become patron noone will (well its probably not true, but then it'd be better just adding a "donation" button and deleting patrons)

And as i see it, in these kind of threads/articles it doesnt matter that much where they are posted. Because if we reached a conclussion like X (say, we decided that we need to pitch 10 grams per gal), then we'd actually just say/teach that in all the newbee threads. So while i love this kind of posts with info, and getting some debate, i dont think it matters much whether its in one place or another. New people wont come near them because they wont understand them but thats why we have a lot of sections. And if you put them in the patrons section you prevent people who are not patrons from debating/adding valuable info.
For me i feel things that could be in the patron sections are big ongoing experiments, proven recipes, etc. That is more valuable info that yes, could be there. Or at least thats how I see it.
 
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Squatchy

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I haven't really landed on what I think should be the case. I am not as active here any more because the lag time frustrates me enough that I started to let you newer guys (thanks) answer then "same ole same ole questions). I guess if people donated enough that we were more modern (and admittedly I don't know shit about IT) then I wouldn't even consider the "patron thing" as a carrot for peps to join.

The cost to become a patron is so little a newbee would save that in honey expense from the ruined batches they would make in a year (or in a batch for that matter) in honey cost. People who are settled in the "how/science" part don't need a recipe. So that's different. I am a patron to share in the cost of having this place to help newcomers to be able to wade past all the bull shit on the web.
 

Squatchy

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So I have not had a chance to read my own link to the reason I started this thread.

But. I thought it might contain info that would shed some light on pitch rates vs logarithmic regeneration. And give us more control on ester production vs clean ester free ferments. Regardless of strain implications.

I think in a broad sweeping way. I don't choose to differentiate as much as some of you between beer yeast /wine yeast and mediums. I get that these things have some differing implications. But you can put a cow in a dessert, or top of a mountain or in a grass field in Michigan and he's still a cow and not a ton of things change about the intrinsic parameters of a cow. I guess I'm saying if you want to get too specific about the lesser pieces to the over all picture you cut your window of learning opportunities down considerably. I'm one who would like to take the big pieces to the table and then dissect them. Rather than throwing the baby out with the batch water.

I realize you can take the same must in volume and treat ot totally the same except for the shape of the vessel and this makes a difference between A/B. And hundreds of other deviations by changing the smallest piece. That's why I never say no when someone wants one of my recipes. I know you won't make what I do. Hell. I have a hard time making my own shit over and over again to turn out the same. In fact it's very close but never the same.

So anyway: Would anyone care to comment on where you might think the the sweet spot stops and starts. As far as number of replications in the biggest part of the biomass in relation to the power band in the fermentation kinetics when the most flavor is produced in any given mead batch?

Dadux. Please can you, for my own satisfaction, show me the mean for reproduction is 25. And also How often our yeast do reproduce in hours/minutes if you have that as well. (BTW I have yet had time to visit the link you posted above)

Lastly I may be wrong. I was wrong about scar transfer to the budded cell until this discovery. But I never contributed the end of lag with the end of logarithmic reproduction. In fact . I always thought the exact opposite. In as much as I thought the logarithmic reproduction started once lag was over. During the time of high Krausen and massive CO2 production. And then at some point they moved over to a stationary phase and it is there where we start to see a decline in population.

I don't have much of a scientific education. I studied chemical recreation and female anatomy when I went to college the first time. It wasn't until I was near 50 that I went back to school to learn anything of value. So I am always hoping to learn more. I must say though. That I am slow to believe things until I can see proof positive info that comes from scientific studies/ pier reviews and the like. Nothing against you at all but I'm saying this so that maybe you can attach some links of the sort. Thanks
 

Dadux

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Dammit. Sorry Squatchy i was writing a lengthy response but my PC shut down. Will try to do it tomorrow, since i want to point you guys to an artcile about the esters and such.
For now the mean i got was from wikipedia (its referenced there, saccharomices cerevisiae article) which states it at 26. And in figure 5 of the paper you sent, that particular strain has 29-30 (not sure since its a graph). For replication time its 100 minutes according to wikipedia (same article, referenced too) under optimal conditions, but im sure i somewhere read 80 as the fastest. More on the ester and replication tomorrow when i post the paper i wanted to show you guys

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Squatchy

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Dammit. Sorry Squatchy i was writing a lengthy response but my PC shut down. Will try to do it tomorrow, since i want to point you guys to an artcile about the esters and such.
For now the mean i got was from wikipedia (its referenced there, saccharomices cerevisiae article) which states it at 26. And in figure 5 of the paper you sent, that particular strain has 29-30 (not sure since its a graph). For replication time its 100 minutes according to wikipedia (same article, referenced too) under optimal conditions, but im sure i somewhere read 80 as the fastest. More on the ester and replication tomorrow when i post the paper i wanted to show you guys

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Sorry to hear the pc thing. I have also had that happen once after writing for over an hour on a piece I was working on.

I also wanted to say that my understanding is that it's once you move past the lag phase this is when logarithmic growth happens. And this is when you see most of the reproduction of biomass along with most of the flavor, fussells, (which half of the flavors we like are actually fussels) H2S and SO2 is made as well as the polysaccharides and phenols. I just realized I ask about a link in the above. :)
 

Dadux

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Ok so here it goes.
Dont restart now, wretched machine!
http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2006.tb00718.x/pdf
I recommend reading it but I'll point out a few things that are very relevant to this discussion
Remember its a white wine article. I know you want the broad strokes, Squatchy so i wont mention much detail in that regard, but always worth keeping it in mind.

1- Independantly from the pitched ammount the highest concentration of yeast is reached after 3-4 days (figure 2, that'd be the growth phase), and the ammount is around 10^8 cells/ml, with slightly more cells the higher the ammount pitched. Also the more yeast pitched, the faster the ferment (figure 1)

2- Squatchy- "I also wanted to say that my understanding is that it's once you move past the lag phase this is when logarithmic growth happens. And this is when you see most of the reproduction of biomass along with most of the flavor, fussells, (which half of the flavors we like are actually fussels) H2S and SO2 is made as well as the polysaccharides and phenols" You are mostly right. Im not checking this but i think polysaccharides are released also/mainly at the end in many cases (differs on the strain). Also you missed glycerol, which has been found to be mainly produced in the first day of fermentation (but also through the growth phase, altough most is early on that phase). Fusels are basically higher alcohols as you probably know. As with many other things (acetaldehyde, acetic acid, others), in low ammounts they give a desirable flavour but too much of them can give undesirable flavours.

3- Into esters and flavour compounds, the article has table II, very interesting. In it you can see that the highest pitch rates give the most flavour compounds overall (rate of 10^7 cells/ml, if you pitch 5 grams of yeast in 4l, close to 1 gal, you are pitching 6.25x10^6 cells/ml, according to the data from mangrove jack that 1 gram of yeast is 5x10^9 cells, altough we already discussed that ammount may be higher or even lower)
But its worth mentioning that it is in fact a lower rate that produces the most esters, 10^6 cells/ml, and that gives over double ammount of ester compounds than 10^7. Also that pitching rate (10^6 cells/ml) has the highest volatile acidity in the non-wild fermented category, and same goes for total acidity. I also recommend you gusy read the conclussions of the article that also has interesting info.

Squatchy- "So anyway: Would anyone care to comment on where you might think the the sweet spot stops and starts. As far as number of replications in the biggest part of the biomass in relation to the power band in the fermentation kinetics when the most flavor is produced in any given mead batch?"
So i tried to more or less answer this. Ferments go considerably faster the more you pitch (at least until 10^7 cells/ml which is 2 grams per liter of must or 8g/gal, over that ammount i have not seen any data but seems obvious to me that the more ammount pitched the faster it goes), and the same goes to total aromatic compounds, but not for esters (big difference here, sweet spot being at/close to 10^6 cells/ml or 0.5 grams of yeast per liter/2g per gal) and acidity. If the ammount of yeast goes from 10^7 cells/ml to 10^8, you got 3-4 replications, and if you start at 10^6 cells/ml you got 6-7 replications. I think the sweet spot is in that renge, depending on what you look for, and there is probably no point flavour or speed wise in pitching less than 2g/gal (10^6 cells/ml).

Obviously as you can guess that other factors, mainly temperature, influence all this. The study was conducted at 20ºC, but we go lower than that so that might mean longer growth phase and/or lower ammount of total yeast cells/ml in the end, different ammount of certain esters as we discussed in other thread...yadda yadda.

I hope you guys find this interesting. I might do some more research and analize those numbers one by one from the flavour compounds later on.
If someone has other info about the topic, go ahead. And sorry if all the numbers gave you a headache, heh. I tried to simplify a bit, but im not that good at it.
 

Lumenbeing

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The question on my mind is, what generation yeast cells are we even starting with? When you pitch a pack of yeast, are you pitching old mothers or daughters of old mothers? Its a bit of the chicken or the egg thing right? Except there are no chickens, only eggs.


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Dadux

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Well, statistically half is first generation, a quarter is second, 1/8 is third and so on and so on.

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Squatchy

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Well, statistically half is first generation, a quarter is second, 1/8 is third and so on and so on.

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I wouldn't say that for certain. Is it possible the lab can manipulate things to be able to separate or manage things so we don't have much of the old bags? I might try to ask that to Lalvin if I ever get a free minute in my life during the day.
 

Lumenbeing

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Well, statistically half is first generation, a quarter is second, 1/8 is third and so on and so on.

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What does "first generation" even mean though? Every yeast cell came from a mother cell right? So are we talking a fresh daughter of a fresh daughter (no bud scars) counts as first generation?


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Dadux

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What does "first generation" even mean though? Every yeast cell came from a mother cell right? So are we talking a fresh daughter of a fresh daughter (no bud scars) counts as first generation?

First generation are cells that have had no other daughters (no bud scars). Second generation are cells that are mothers of 1 generation (1 bud scar) Third generation 2 bud scars and so on.

SO imagine you have 2 cells. First replication you have 4 cells, second you have 8. From those, 4 are "newborn" with no scars. 2 have 1 scar and 2 have 2 scars. By statistic half the cells wont have any scars, because the colony duplicates every X minutes.

And Squatchy you are not getting many old bags anyway. I dont think they can separete them any way (that is worth the money). 75% of the cells have 1 or none bud scars, i think thats enough. But hey if you write to them let us know. After all i could be wrong.
 

Squatchy

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I hardly doubt they can separate either. I was just saying. How we quickly land on "the obvious". And sometimes "the obvious" isn't what we think. I remember the first time it came to my realization, that at any time during an active ferment half our biomass ate brand new cells, and how much I tripped out on that whole concept. It still freaks me out to stop for a second and think about it
 

HeidrunsGift

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First generation are cells that have had no other daughters (no bud scars). Second generation are cells that are mothers of 1 generation (1 bud scar) Third generation 2 bud scars and so on.

SO imagine you have 2 cells. First replication you have 4 cells, second you have 8. From those, 4 are "newborn" with no scars. 2 have 1 scar and 2 have 2 scars. By statistic half the cells wont have any scars, because the colony duplicates every X minutes.

And Squatchy you are not getting many old bags anyway. I dont think they can separete them any way (that is worth the money). 75% of the cells have 1 or none bud scars, i think thats enough. But hey if you write to them let us know. After all i could be wrong.

So this article is beyond my level of biology expertise, but I think I grasp the major concepts. Dadux, according to the article it seems like the older the mother cell becomes, the shorter the life expectancy of the daughter cell. As it becomes older and has replicated more and more, it continues to scar again and again. Ie, the more scars the mother has when the daughter is made, the shorter the life expectancy (and I would assume the lower the health/viability) of the daughter.

So I would think that the question brought up about the quality/viability of the yeast cells isn't not just about how many scars that particular cell has (ie, if its 1st or second generation), but how many the mother had. Sure its better that our 5 gram pack of dried yeast all have no scars, but isnt it just as important that their mothers didnt have, say, 10-15 scars? Because if the daughter's mother had a lot of scars, wouldn't that particular daughter's viability be very low? The only reason why I think this might not be an issue, is that since yeast can replicate so much, you may only need a small number of both daughters AND mother cells that had little to no scars and those small number of yeast cells are the ones that go on to produce the large, robust colony. In other words, you only need a few really good yeast cells among a lot of bad ones to make a strong, healthy colony.

Here are a couple other questions that popped up that I had, Dadux maybe you could help with these as well:

-How long do yeast cells in a fermentation live? Do most of the yeast that is pitched live throughout the fermentation, not just the ones that are replicated later on?
-What "signals" the colony to stop exponential growth/massive reproduction, and go into stationary phase? Colony biomass limit? Alcohol concentration? If yeast are capable of living for a long time, what causes there to be so much either dead or inactive yeast to be piling up already (prior to the "signal" that starts stationary phase)?

I have only read the original link posted by Squatchy so far so sorry if some of these questions are answered in the links posted later on
 

Dadux

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So this article is beyond my level of biology expertise, but I think I grasp the major concepts. Dadux, according to the article it seems like the older the mother cell becomes, the shorter the life expectancy of the daughter cell. As it becomes older and has replicated more and more, it continues to scar again and again. Ie, the more scars the mother has when the daughter is made, the shorter the life expectancy (and I would assume the lower the health/viability) of the daughter.

So I would think that the question brought up about the quality/viability of the yeast cells isn't not just about how many scars that particular cell has (ie, if its 1st or second generation), but how many the mother had. Sure its better that our 5 gram pack of dried yeast all have no scars, but isnt it just as important that their mothers didnt have, say, 10-15 scars? Because if the daughter's mother had a lot of scars, wouldn't that particular daughter's viability be very low? The only reason why I think this might not be an issue, is that since yeast can replicate so much, you may only need a small number of both daughters AND mother cells that had little to no scars and those small number of yeast cells are the ones that go on to produce the large, robust colony. In other words, you only need a few really good yeast cells among a lot of bad ones to make a strong, healthy colony.

Here are a couple other questions that popped up that I had, Dadux maybe you could help with these as well:

-How long do yeast cells in a fermentation live? Do most of the yeast that is pitched live throughout the fermentation, not just the ones that are replicated later on?
-What "signals" the colony to stop exponential growth/massive reproduction, and go into stationary phase? Colony biomass limit? Alcohol concentration? If yeast are capable of living for a long time, what causes there to be so much either dead or inactive yeast to be piling up already (prior to the "signal" that starts stationary phase)?

I have only read the original link posted by Squatchy so far so sorry if some of these questions are answered in the links posted later on

First of all i must say i dont agree with your logic per se. It might be so, but let me propose something else that could be perfectly true as well.
What if it does not matter the number of scars the mother has? what if these people just measured the ammount of times they reproduced but the important thing is actual time lived. According to this study, a cell that grows on a rich medium and reproduces every 100 minutes, at her lets say 12th reproduction will give a daughter cell with less lifespan. But imagine the following, a cell that has not reproduced because had no nutrients avalieable that has lived 20h (1200 minutes, the same as the other mother cell) eventually gathers enough nutrients to reproduce and gives a daughter cell. WHo is to say that daughter cell wont also have a reduced lifespan? Yes, they measured reproductive cycles. But its as probably its not number of divisions related, but time related.
Its as if i say that a woman has 15 children, the last one is more likely to have problems becasue its the last one. But its not true. Child problems are related to the mother's age. A mother's 15th child will have more chances of suffering certain disseases just because the mother is older, not because of its 14 previous brothers and sisters. The initial statement might be absolutely false. We should at least consider the possibility that daughter cells life expectancy might be related to mother age and not to the mother's previous reproductions. This could be specially interesting for liquid yeast packs.

About the mother reproductions you mention on paragraph 2, statistically again, if we have X new cells, and thus X mothers, X/2 mothers will be the first daughter they have, X/4 the second, X/8 the third and so on. Sure, some mothers will have 10 scars, but how many? 1/2^10. I would not worry much about that. specially since ther eis little we can do about it.

I'll also try to answer your questions but im no microbiologist. Maybe someone else is, loveofrose or some other, and can also chime in, but as far as i know/think:

1-viability, life/death and active/inactive are different concepts. Some good ammount of yeast quit early, but that does not mean its dead. I have no real idea how many of those are dead and how many just inactive. In the first link i posted, more than 50% of the yeast (if i remember correctly) seem to be able to make colonies until after 15 days or so when cultured in water, and after 25-30 none can. But from must/mead to water there are a lot of differences, good and bad. I'd say that most of the yeast pitched lives the first few days/week but is inactivated at some point. Just watch your fermentations. When you see the speed go down, the cells are quitting, be that dying or just inactivating. I cant really give more reliable info on this. I have not read on anyone measuring this, maybe because its pretty hard to differenciate between pitched yeast and born yeast cells, specially in large ammounts.

2- I might be wrong on this one, but if i remember correctly, stationary phase could probably be divided in two. Early, the inactivation/death will more or less be countered by some new cells being "born", and the total active yeasts plateaus. After that, at some point the cells just start creating reserves when they realize the sugars start to dwindle. Im not 100% sure, but I'd say there is a stop/decrease in reproduction because of some secreted substances that signal the inhibition of duplication in other yeast cells. When too many cells secrete this molecules (I read those might be short chain lipids, or that among them might be those) the growth is inactivated. And they probably start accumulating sugars in glucogen when they "sense" the ammount of sugars go down. Again, its been some time since i read up on the topic so thats all i can tell you. I would like to give you a more detaild explanation but for now thats what i have. If someone else knows more, maybe they can correct/complete this. If not and you still interested, remind me in a few days and i can dig up some stuff up.

3- I dont understand this " If yeast are capable of living for a long time, what causes there to be so much either dead or inactive yeast to be piling up already (prior to the "signal" that starts stationary phase)?"
Maybe you refer to the lees but i dont see that much lees early on. Sometimes also yeast fall to the bottom but that does not necessarily mean that they are not fermenting. But as i said i dont see much/any until at least 5-7 days have passed since pitch, and thats already stationary phase.
 

Squatchy

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So one thing I always find amazing is this:

People seem to think that once a ferment stops fermenting once the ABV tolerance is meet that the yeast die of alcohol poisoning. This is at least partly not true. Proof is here: Let that same ferment sit for 2 months , 6 months, 1 year. You pick. Add some water to dilute the ABV and they go back to work. I don't think it's because one or two somehow were able to survive for some reason. Why would some die and others not. So, certainly something else, or a combination of something else has caused some to die. But obviously some lived. I think that the ABV limit somehow stops their ability to assimilate sugar. And that's why they stop fermenting but don't die. At least not right away. And as we know. Some start dying in just a few days after fermentation starts.
 
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