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HeidrunsGift

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Dadux/Ryan, thanks for the responses--definitely some technical stuff.

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.

OK that makes sense, that several scars do not necessarily correlate with a mother cell being very old. I must have incorrectly assumed that while reading the article. I will say that I would be surprised if the s. cerevisiae cells in our meads reproduce every 100 minutes though, for the reason you pointed out below in your first post: suppose once the bio mass has reached 1.024 KG (a little over 2.2 pounds, on the 9th replication; Stasis's math below), it hits stationary phase. Assuming it does 1 - 2 replications during lag phase, that leaves either 7 or 8 replications to do during exponential growth before it hits stationary phase and most growth comes to a stop. If the yeast are replicating every 100 min, then this leaves between 7 x 100 and 8 x 100 minutes for exponential growth phase, which comes out to between ~11.5 and 13.3 hours. I was always under the impression exponential growth lasted for several days, not about half a day. This means that replication would have to take far longer than 100 minutes. So in theory I agree, it just seems unreasonable that cells could still be relatively "young" and have gone through tons of replications.

[/QUOTE] 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. [/QUOTE]

Thats correct, I was referring to all the lees and how much cloudier the mead gets when I stir, even after only a couple days go by. I was just wondering why they seem to be going inactive, or going dormant and falling to the bottom when the article indicates that they are capable of doing so many replications.

I think that the ABV limit somehow stops their ability to assimilate sugar.

Yeah, similar to the comment above, I'm kind of getting at what causes a healthy colony of yeast that are capable of doing many many more cycles of replications to suddenly slow down. I assumed alcohol might be one factor. Dadux mentioned that they might start to secrete "short chain lipids" to start to "inactivate" growth. I'd be curious to read more up on these signal substances, and if there was a way to repress them to extend the exponential growth stage?

So I'm not sure if my questions will be able to help our techniques for our mead or make it better, they were just things that popped up in my mind as I was reading the article :) Thanks again for your inputs gents!
 

HeidrunsGift

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Oh and before I forget, on the topic of good reading material, there is an article in the latest copy of WineMaker (August-September) by Daniel Pambianchi that covers in depth what yeast are going through during fermentation - role of O2; nitrogen, sugar, fatty acid, ester, organic acid, and sulfur metabolisms; aroma/flavor compounds, etc.) A lot went over my head the first time I read it so I'll be re-reading that one. He also has a book called Techniques in Home Winemaking, anyone read that?
 

Squatchy

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Charlie. Thanks for pointing us to that read. I never can find enough to read. I'm cursed sometimes with too much of an inquisitive mind. The statue of the thinker is me in every way. I know you are cursed/blessed with the same hard wire. I really don't think it's a curse. It's what pushes some of us to move forward beyond established ways of thinking and self imposed boundaries.

BTW. A good friend of mine works/ and has for many years at Dog Fish Head. One of the biggest micro breweries in the nation. I was talking to him the other day and he mentioned that they do it so the ferment is finished by the time the yeast have replicated 6 times. Not sure what that means exactly in reference to the "timeline" we are tossing about. But I thought I would mention it anyway.
 

Dadux

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Dadux/Ryan, thanks for the responses--definitely some technical stuff.



OK that makes sense, that several scars do not necessarily correlate with a mother cell being very old. I must have incorrectly assumed that while reading the article. I will say that I would be surprised if the s. cerevisiae cells in our meads reproduce every 100 minutes though, for the reason you pointed out below in your first post: suppose once the bio mass has reached 1.024 KG (a little over 2.2 pounds, on the 9th replication; Stasis's math below), it hits stationary phase. Assuming it does 1 - 2 replications during lag phase, that leaves either 7 or 8 replications to do during exponential growth before it hits stationary phase and most growth comes to a stop. If the yeast are replicating every 100 min, then this leaves between 7 x 100 and 8 x 100 minutes for exponential growth phase, which comes out to between ~11.5 and 13.3 hours. I was always under the impression exponential growth lasted for several days, not about half a day. This means that replication would have to take far longer than 100 minutes. So in theory I agree, it just seems unreasonable that cells could still be relatively "young" and have gone through tons of replications.

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.

Thats correct, I was referring to all the lees and how much cloudier the mead gets when I stir, even after only a couple days go by. I was just wondering why they seem to be going inactive, or going dormant and falling to the bottom when the article indicates that they are capable of doing so many replications.



Yeah, similar to the comment above, I'm kind of getting at what causes a healthy colony of yeast that are capable of doing many many more cycles of replications to suddenly slow down. I assumed alcohol might be one factor. Dadux mentioned that they might start to secrete "short chain lipids" to start to "inactivate" growth. I'd be curious to read more up on these signal substances, and if there was a way to repress them to extend the exponential growth stage?

So I'm not sure if my questions will be able to help our techniques for our mead or make it better, they were just things that popped up in my mind as I was reading the article :) Thanks again for your inputs gents!

Yes, as i mentioned, 100 minutes is optimal conditions, and probably at 37ºC. Neither is true when it comes to mead.

Im not so sure that falling to the bottom and going dormant/dying go hand in hand. Same way your mead remains cloudy for months after the ferment is done, but the yeast is definitely not fermenting anything. I dont know how much of that falling yeast is actually dormant or dead.

Alcohol mainly affects the membrane, increasing its fluidity to dangerous levels. Its been documented that strains really have little to do with alcohol tolerance (maybe except turbo yeast, have not read anything about those) and that nearly any strain that is well fed, nutriens and sugar wise, with enough oxigen to cover its needs, and some other parameters, can constantly reach 16 or even 17% ABV. Independantly of the strain. As far as i've read the strains basically change slightly the composition of the membrane. More alcohol tolerant strains have in the membrane lipids that decrease membrane fluidity, which counteracts somewhat the ethanol effects (mostly oleic acid). And as we know, damaged membranes basically stop yeast functions alltogether. So its not only about sugar assimilation, but yeah, that is included.

I only got this lying around about the fatty acids, http://onlinelibrary.wiley.com/doi/10.1002/yea.3071/full
I must say i've read different things about this, from "they dont do anything in normal ferments" to "it inhibits growth" to this "they are toxic and kill the yeast cells". This article is recent enought to give it some credit, and its true that growth inhibition and death are things that go hand in hand many times. Im not an expert in the matter in any way, so feel free to reach your own conclussions and do your own research. Also as far as i know the best to stop them from creating these acids are minimizing yeast stress.
Also this article explains more about the stationary phase https://www.ncbi.nlm.nih.gov/pmc/articles/PMC372915/
 

Dadux

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Oh and before I forget, on the topic of good reading material, there is an article in the latest copy of WineMaker (August-September) by Daniel Pambianchi that covers in depth what yeast are going through during fermentation - role of O2; nitrogen, sugar, fatty acid, ester, organic acid, and sulfur metabolisms; aroma/flavor compounds, etc.) A lot went over my head the first time I read it so I'll be re-reading that one. He also has a book called Techniques in Home Winemaking, anyone read that?

That one is great, but also he did another one in 2011 that is a must.
2011- https://winemakermag.com/1078-understanding-yeasts
2017- https://winemakermag.com/1696-how-wine-yeast-works
 

Squatchy

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I have a friend that has worked at Dogfishhead for many years. We were talking the other day about some of this. He said ( and they make enormous batches) their scientist figure out ptch rates so that the sugar is gone buy the time the unscared mother has budded six times.

He has just opened his meadery this past weekend. He, and many others pitch more yeast than what most people would pitch here in our community. Even though I have advocated here for a long time to raise the pitch rates. I use more than what I advocate here a lot of the time. Can't really go wrong using more yeast. Ever.
 

darigoni

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How much yeast are they pitching?

And is it more than ?? buds, but no more than six buds?

??<= buds <= 6

Or is the sweet spot 6 buds?
 
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Squatchy

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Well I suppose the amount they pitch varies from one style of beer to another and the OG. Or were you asking about my professional mazer friends? Some guys will sometimes pitch 4-5 grams per gallon.

He said they shot for 6 generations. As you know not every yeast is on the exact page in the chronological order of things in a biomass of 350-450 million cells per milliliter.
 

Squatchy

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So am I having a dumb moment or what? I can't seem to find the link from Dadux's stuff that leads to the daughter cell reproduction/ declination of viability piece he posted here before. ANybody?
 

mannye

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Read this thread with a lot of interest. Very interesting. I have been thinking about pitch rates especially when we are using very low temps and I have been thinking it may be wise to increase the amount of yeast or maybe even stagger the pitch by reserving some must and making a second starter that's pitched, say, on day two or three. This might assure that the "virgin mothers" last a few days longer during the most active part of the fermentation.

Dunno... just a thought. I will be starting some batches next week with D-47 at around 60-62F and this might be a good opportunity to try it. I was also going to experiment with some lager yeasts at 50-55F to see what they can do. With one gallon test batches I can easily pitch a 5 gallon amount and not spend too much on testing.

At the usual 5 gallon size, all that original yeast can get pricey.
 

Squatchy

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At $1.50 per 5 grams. Yeast is the very cheapest expense we have in a mead batch. I generally use 15 grams for a 5-gallon batch. So $4.50. That's pennies compared to honey and/or wine kits, frozen fruit. I just spent $750 for a 5-gallon bucket of Tupelo. Add half that to a 200 dollar wine kit to make 8 gallons of melomel in a $1900 temp controlled stainless conical fermenter. And then age it in a $200 barrel. Seems strange to even consider a few packs of yeast. Just saying brother.
 

mannye

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At $1.50 per 5 grams. Yeast is the very cheapest expense we have in a mead batch. I generally use 15 grams for a 5-gallon batch. So $4.50. That's pennies compared to honey and/or wine kits, frozen fruit. I just spent $750 for a 5-gallon bucket of Tupelo. Add half that to a 200 dollar wine kit to make 8 gallons of melomel in a $1900 temp controlled stainless conical fermenter. And then age it in a $200 barrel. Seems strange to even consider a few packs of yeast. Just saying brother.

Not when you're using a lot of Wyeast Smack Packs (which I love) at 6 to 8 bucks a pop! :)

And yeah... All the other things are super expensive... so I ain't got no mo' money left!
 

Squatchy

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There are tons of great dry yeast that make great meads. And none of them are any slower than your 1388. I've won many medals in comps with 3 month old meads. You ought to try something new sometime
 

mannye

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There are tons of great dry yeast that make great meads. And none of them are any slower than your 1388. I've won many medals in comps with 3 month old meads. You ought to try something new sometime

NO! CHANGE IS BAD!!! lol :)

Of course I'm trying different strains. I stick with my tried and true for big batches of 5 or more gallons but I love experimenting with different strains in one gallon batches.
 

Squatchy

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I have about 15 tried and true strains. Using just one strain doesn't work for me. I have done so many test batches of several strains all made with the same must to compare side by side. One yeast to the next can show you a huge difference strain to strain. SOme are not very good at all compared to the ones that work best for a given honey. I feel like if I made everything with one strain. I would make more than half with the wrong yeast so half of my finished product would be some of the much lesser successful batches.

I have probably used at least 25 strains and continue to explore with new strains constantly
 

Squatchy

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Being new to mead making, I've mostly stuck to Lalvin wine yeasts, with one BOM batch in the works. in your 25-ish strain repertoire, are there any standouts you can point a new guy to for clover/wildflower/other less-expensive honey?

With affordability aside. I don't just clump together one honey with one strain. There a few other things to consider as well. So I would need more info to give you the best answer. But I can say this. I use only Llalemonde yeast mostly because they give us info for each strain and the other companies do not. You also need to consider your ability to control temps. And you might choose to one of equal choices one over the other if it adds mouth volume or other strain specifics. This is how then I often end up with split batches that I blend back together at the end of the day. I split up honey into like families for the most part. Some are fruit. Some are flowery. Often they are combined. Some are savory or earthy. SOme are spicey. Some are very delicate. And some would ask only to make a traditional because of its divine uniqueness.

I don't have time just now but I will write a piece about honey and yeast connections very soon and post it as a new thread

You will aslso do well to listen to the gotmead live podcast that starts on 9/5/17
 

darigoni

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I don't have time just now but I will write a piece about honey and yeast connections very soon and post it as a new thread

I think you covered this, along with suggested yeasts per mead category, in your pod casts, but VERY much look forward to seeing it in black and white!
 

Squatchy

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I think you covered this, along with suggested yeasts per mead category, in your pod casts, but VERY much look forward to seeing it in black and white!

I did. But I have found a better way to present and also have found a better way of understanding how to match them up
 
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