Fundamental shift in yeast starter preparation?

[cactusgarrett]

I thought I'd spin this off of the yeast slurry discussion; don't want to take that over.

@renstyle mentioned listening to the Bru Lab episode 80 about yeast, which I just finished. It's got my mind reeling; not really sure what to think yet. In the episode, they reference an earlier episode (062) where work was done to show that yeast starters prepared at 1.008 gravity produced 500% more, healthy (quantity) yeast cells due to the yeast relying on respiration. The takeaway is you can use less extract to prepare the starter, and pitch far less than the online calculators suggest.

The reasoning seems logical, and I can usually be talked into considering anything with seemingly sound logic, but them referencing the work (from episode 62) that suggests a starter wort of 1.008 is best for growth (with enough nutrient/nitrogen)? It goes against ALL the online starter calculators to date, and I don't know what to think.

And the idea that when they asked themselves "how much nutrient/nitrogen do you use?", they started with 5g in 1-2L, then noted the Wyeast instruction is (for their product) 2.2g in 5gal - that comes out to 0.1g/1L, not 5g. Other resources note that if you use too much of these nutrient products, you can be doing harm by poisoning the yeast with too much nutrients such as Zinc.

 

[day_trippr]

Good luck, but you lost me at Bru Lab...

Cheers!

 

[cactusgarrett]

Good luck, but you lost me at Bru Lab...

Cheers!

Right. I mentioned it in the other thread - I'm trying to temper any biases against the Brulosophy guys and their "hot takes" (mine and others) while digging into this. This work, though, was actually done by Maria Moutsoglou, who (at the time) worked for Sierra Nevada (at Molson Coors right now). I'd like to think that brings a bit more gravitas to the topic.

 

[Bassman2003]

This should be pretty easy to test. Just make two starters side by side, one with the lower gravity wort and see how much slurry you end up with.

 

[cactusgarrett]

This should be pretty easy to test. Just make two starters side by side, one with the lower gravity wort and see how much slurry you end up with.

The studies state, though, that despite better cell growth, the cells are better equipped to ferment from respiration (vs fermentation), and that you can pitch 500% fewer cells into standard wort. Seems like this would throw off the "count by volume/weight" aspect.

 

[VikeMan]

This should be pretty easy to test. Just make two starters side by side, one with the lower gravity wort and see how much slurry you end up with.

I havent listened to the podcast, but I suspect the amount of O2 and nutrients become critical.

In the episode, they reference an earlier episode (062) where work was done to show that yeast starters prepared at 1.008 gravity produced 500% more, healthy (quantity) yeast cells due to the yeast relying on respiration.

The studies state, though, that despite better cell growth, the cells are better equipped to ferment from respiration (vs fermentation), and that you can pitch 500% fewer cells into standard wort. Seems like this would throw off the "count by volume/weight" aspect.

Is it 500% more cells produced in the starter, or is it 500% less cells needed into the wort?

 

[cactusgarrett]

Is it 500% more cells produced in the starter, or is it 500% less cells needed into the wort?

From memory, it was 46% more cells generated in the "starter" (lab material) and of those cells, 500% fewer were needed for a comparable fermentation of "standard" gravity wort/beer.

 

[cactusgarrett]

I suspect the amount of O2 and nutrients become critical.

Mainly nitrogen.

 

[cactusgarrett]

I also want to be clear that I'm not trying to make this into be a Brulosophy bashing/bias session. I supposed to give this discourse a fair shake I should have omitted that they reported on it in the first place.

 

[McMullan]

Yeast are living organisms. Treat them as such and you will be rewarded for your respect of living things. If one wishes to select for the best possible yeast cells to ferment malted barley wort then - wait for it - culture them in malted barley wort. The flawed assumptions based on very limited data do not refute what we already know inside out. The inconvenient truth. Brulosophy seem to get so awesomely excited about all kinds of unconfirmed ****, in the name of advertising mainly. That's what Brulosophy is all about, right?

 

[cactusgarrett]

Brulosophy seem to get so awesomely excited about all kinds of unconfirmed ****, in the name of advertising mainly. That's what Brulosophy is all about, right?

Again, this isn't Brulosophy's work, it was Maria Moutsoglou (at the time) at Sierra Nevada. Can we please curb the Brulosophy hate for an attempt at reasonable discourse here?

 

[VikeMan]

I just listened to episode 62, where Maria Moutsoglou actually talked. A couple of takeaways:

The ratio of Carbon to Nitrogen in the reduced gravity, nitrogen supplemented wort was 100 (vs 850 for the regular starter wort).

She did not say that you could pitch 500% less yeast into the main batch of wort. It was the host who said something about 500% in a rambling, frankly indecipherable statement. At the point where he said it, in some sort of a perceived epiphany, nothing that went before suggested that you could pitch 500% less yeast. And again, Maria Moutsoglou made no such claim.

Before I'd get too excited, a big thing that's missing here is tasting panel data.

And here, I believe, is the paper, which I have not read through yet:
https://onlinelibrary.wiley.com/doi/full/10.1002/jib.621
ETA: According to the abtract, the 46% increase in cell production was for the 2 Plato low C:N wort vs the 2 Plato high C:N wort. It was not in comparison to a "normal" gravity starter wort (in spite of what the podcast may have implied).

 

[McMullan]

'Haters' aside, reasonable discourse involves what here? Maria what's-her-face is entitled to her opinions, but has anyone with any credibility actually confirmed her opinions in a way considered convincing? I suspect such a grossly simplistic idea has been considered numerous times independently. Perhaps there's a reason we haven't accepted the idea already?

 

[TheMadKing]

I just listened to episode 62, where Maria Moutsoglou actually talked. A couple of takeaways:

The ratio of Carbon to Nitrogen in the reduced gravity, nitrogen supplemented wort was 100 (vs 850 for the regular starter wort).

She did not say that you could pitch 500% less yeast into the main batch of wort. It was the host who said something about 500% in a rambling, frankly indecipherable statement. At the point where he said it, in some sort of a perceived epiphany, nothing that went before suggested that you could pitch 500% less yeast. And again, Maria Moutsoglou made no such claim.

Before I'd get too excited, a big thing that's missing here is tasting panel data.

And here, I believe, is the paper, which I have not read through yet:
https://onlinelibrary.wiley.com/doi/full/10.1002/jib.621
ETA: According to the abtract, the 46% increase in cell production was for the 2 Plato low C:N wort vs the 2 Plato high C:N wort. It was not in comparison to a "normal" gravity starter wort (in spite of what the podcast may have implied).

And this about wraps it up for me. She's comparing which is the more limiting carbon or nitrogen, and it sounds like nitrogen. Which makes sense when you realize that most off the shelf yeast nutrients smell like ammonia. It sounds like she performed a perfectly valid test of the effectiveness of common yeast nutrients that was garbled by poor wording or misunderstanding by the host.

Thanks for clearing that up Vike!

 

[VikeMan]

Thanks for clearing that up Vike!

To be fair though, she did also discuss respiration vs. fermentation, and the (true) fact that respiration is a lot more efficient way to make ATP (energy, which is needed for growth and propagation) than fermentation is. And a way to force respiration (and less fermentation) is to limit the carbon concentration and provide enough nitrogen.

That said, will a starter done that way result in better (tasting) beer?

 

[cactusgarrett]

reasonable discourse involves what here?

Along the lines of Vike wrote. I'm looking for legit reasons other than gut reactions and "it's what we've always done before" to not consider it further.

Before I'd get too excited, a big thing that's missing here is tasting panel data.

My swiss cheese memory for data aside, the gist of what was being put forth is what I wanted to discuss here - making starters at 1.008. You're also putting forth good points that Maria Moutsoglou brought data, and the host is making extrapolations from it

 

[DuncB]

@cactusgarrett
This thread
is very good about yeast growth and explains how and why some of the experimental findings aren't that useful in the real world.

https://suigenerisbrewing.com/index.php/2022/09/20/optimizing-yeast-starters/

 

[Bramling Cross]

I just listened to episode 62, where Maria Moutsoglou actually talked. A couple of takeaways:

The ratio of Carbon to Nitrogen in the reduced gravity, nitrogen supplemented wort was 100 (vs 850 for the regular starter wort).

She did not say that you could pitch 500% less yeast into the main batch of wort. It was the host who said something about 500% in a rambling, frankly indecipherable statement. At the point where he said it, in some sort of a perceived epiphany, nothing that went before suggested that you could pitch 500% less yeast. And again, Maria Moutsoglou made no such claim.

Before I'd get too excited, a big thing that's missing here is tasting panel data.

And here, I believe, is the paper, which I have not read through yet:
https://onlinelibrary.wiley.com/doi/full/10.1002/jib.621
ETA: According to the abtract, the 46% increase in cell production was for the 2 Plato low C:N wort vs the 2 Plato high C:N wort. It was not in comparison to a "normal" gravity starter wort (in spite of what the podcast may have implied).

Thanks for that, Vikeman. I started and then deleted a couple different posts that opened with, "Five-hundred percent is an awfully big number. What sort of starter volume are they using? It must be close to a full batch size?"

I get it, now. Thank you.

 

[cactusgarrett]

To be fair though, she did also discuss respiration vs. fermentation, and the (true) fact that respiration is a lot more efficient way to make ATP... than fermentation is. And a way to force respiration (and less fermentation) is to limit the carbon concentration and provide enough nitrogen.

Right. For those who haven't listened to the episode, that's the whole basis of the study and the concept the host is putting forth when suggesting starters can be made with less sugar.

And to be clear, I don't buy this all, either, but I wanted a good reason (aside from it not passing the sniff test) to not consider it further.

 

[SanPancho]

whatever happened to the ol' "OLIVE OIL IN YOUR STARTER" hubbub from a while back.....

 

[CascadesBrewer]

Right. For those who haven't listened to the episode, that's the whole basis of the study and the concept the host is putting forth when suggesting starters can be made with less sugar.

I have not listened. My impression (based on a tour of a local yeast lab) is that during fermentation there they continually feed the yeast sugars to keep the gravity levels lower than what kicks off the Crabtree effect. This translates into much more cell growth. Are they just making a starter in 1.008 wort, or are they continually keeping the wort at around the 1.008 gravity level?

 

[cactusgarrett]

Are they just making a starter in 1.008 wort, or are they continually keeping the wort at around the 1.008 gravity level?

Starter in 1.008 medium and making sure they hit a specific level of nitrogen in order to rely on respiration instead of fermentation. They didn't mention anything about feeding to maintain 1.008, so I'm assuming that didn't happen.

 

[cactusgarrett]

This thread
is very good

Great stuff; thanks.

 

[McMullan]

Is respiration more efficient for yeast cells? Really? It depends on the yeast and its environment. If we look beyond a simple comparison of how many mols ATP get produced from a mol of glucose, fermentation vs respiration; due to the ecology of brewer's yeast there are actually proteomic restrictions making respiration in high carbon environments far too costly, metabolically. But the logic that we therefore simply reduce the carbon/energy/gravity and increase nitrogen in starter wort, to increase growth therefore biomass, is expressing a form of biased tunnel vision. Being essential for growth, e.g., for nucleic acids and proteins, yes, nitrogen is required, but glucose/energy/ATP is required to the extent biomass production is positively correlated with wort gravity, not just nitrogen. We use relatively low gravity (<1.010) culture media in labs to propagate yeast, but these procedures are optimised to produce yeast cultures for non-brewery use. The aim isn't to maximise biomass. On the other hand, brewers follow procedures that maximise biomass so sufficient yeast cells for successful brewery fermentations get pitched. There is enough nitrogen and carbon in malted barley wort with an SG=1.040 to support sufficient growth in brewing environments. It works just fine. There's nothing broken here. Nothing to fix. We don't just want our brewer's yeast cells to grow, we want them adapted to ferment brewery worts. Let's just call it 'a gut reaction' and stop wasting valuable brewing time trying to be different for the sake of being different.

 

[CascadesBrewer]

This thread
is very good about yeast growth and explains how and why some of the experimental findings aren't that useful in the real world.

That Sui Generis Brewing is a well written and useful approach, especially for building up from small cultures. It does point out the positives of the study by Maria Moutsoglou:

Increasing nitrogen content has a dramatic impact on yeast growth, as nitrogen (which is used to make DNA and proteins) is often a limiting nutrient for yeast growth. A recent study found that using low-sugar (~1.008) wort with high nitrogen (~30g yeast extract [essentially Fermaid-O] per liter of wort) produced nearly 50% more yeast than the same gravity wort with minimal additional nitrogen added. For more details, see the episode 62 of the Bru-Lab Podcast. At home (or in the brewery) this isn’t really a practical option, as yeast extract is not exactly cheap.

Note the "30 g of Fermaid-O per liter" requirement. MoreBeer sells Fermaid O at $0.12/g in a 120g pack (and $0.08/g in 750g pack). That would add $7.25 (or $4.96) to the cost of a 2L starter. That is likely not very cost effective.

The article recommends adding only 5g per L, which reduces that cost down to $1.25 (or $0.83) for a 2L starter. That seems more reasonable. The other option is using using DAP. I think he recommends using DAP at around 0.8 g/L. At the $0.04/g price of DAP, that would add about $0.07 per 2L starter. (This amount of DAP is based on a recommendation I saw to add 0.5g to 0.75g per gallon of wort, and the article's recommendation to use 5X the recommended amount.)

But what this paper does show to us is that increasing nitrogen content will have a positive effect on yields. I add ~5 g/L yeast extract to my starters, at a gravity of 1.040, and see a yield increase of ~10%. Even just DAP, at 5X (or more) the manufacture’s recommended dose, can increase yields. If you do this in the final stage before pitching the yeast, be sure to remove as much of the wort as possible. Yeast can make some pretty unpleasant compounds under high nitrogen conditions.

But then, a 10% increase is not much to get excited about. The recommendation to keep ale yeast starters at 30C and lager yeast starters at 25C might have more impact.

I do wonder if there is a specific yeast nutrient that is "best" to add to a starter and at what rate. I have generally added "some" "yeast nutrient" to my starters. Over the years I have not been very consistent on the amount or the type of yeast nutrient I have used. Lately I have been adding 1g to 2g of Wyeast nutrient to a 1L starter.

 

[McMullan]

Peptone and yeast extract are pretty standard, but far too expensive to waste on making starters that only produce about 10% more biomass. With such a marginal increase I'm not sure what all the fuss is about. It's much more effective and cheaper to make a bigger starter or more starters.

 

[VikeMan]

Oh, great. Brulosophy has now done an experiment based on their misinterpretation of Maria Moutsoglou's comments and/or the paper. (Surely they read the paper, right? I mean, right?) They basically think that Maria Moutsoglou told them that instead of making a starter of "X" volume @ 1.040, make a starter of the same volume but at 1.008.

 

[cactusgarrett]

Brulosophy has now done an experiment based on their misinterpretation of Maria Moutsoglou's comments and/or the paper.

Seems like people would be just as unhappy if they didn't do any work on this - isn't that the point of them doing the testing? I don't jock their nuts, but man - seems like they're 100% damned if they do and damned if they don't around here.

What work/detail on Brulosophy's part would be sufficient for the detractors to this concept consider a shift in their own thinking?

 

[AlexKay]

I give it about as much credence as if a poster on these forums said "I get great results using a lower-gravity starter," which is to say, not none, but perhaps not enough to change my own practices.

 

[jdauria]

Interesting, but being Brulosophy, I will wait to see other sources say the same. Personally, I have given up on starters based on cell counts in favor of the Shaken not Stirred method that Denny Conn talked about on a episode of Experimental Brewing. Shaken, not Stirred: The Stir Plate Myth Buster | Experimental Homebrewing Since trying this method six months ago, my stir plate has been on the shelf gathering dust. Have brewed dozen or so beers and the method works, fermentation still takes off like normal and beers fully ferment out, even with lagers.

 

[VikeMan]

Seems like people would be just as unhappy if they didn't do any work on this - isn't that the point of them doing the testing? I don't jock their nuts, but man - seems like they're 100% damned if they do and damned if they don't around here.

What work/detail on Brulosophy's part would be sufficient for the detractors to this concept consider a shift in their own thinking?

What work/detail on Brulosophy's part would be sufficient for the detractors to this concept consider a shift in their own thinking? I dunno. Maybe an experiment based on what Maria Moutsoglou (or her paper) actually said, and not on a misunderstanding of her work.

IOW, if they are going to be "doing the testing," they ought to test something that was actually suggested by the research.

ETA: They are of course free to test whatever they want. Just don't tie it to a person/paper who never suggested it.

 

[Bassman2003]

It is my understanding the stir plates are more about driving off CO2 than ingesting O2. I read Denny's page and I saw no mention of CO2 or any real reason SNS is better than a stir plate, just different. SNS pitches the entire contents of the starter into your beer. That alone is a reason to choose another method for many brewers. Whatever method is fine but they are all going after the same goal. I happen to have the exact opposite experience as Denny with starters. After 19 years of brewing I finally made a stir plate out of a computer fan and think it is much better than my previous static starters. I run them at room temp, cold crash the night before and siphon off the liquid before pitching.

I like Denny. He was a large factor in me starting to brew all grain from extract many years ago, but poo pooing industry standard practice just because one does something differently is not how I would do things. Stir plates provide constant agitation as well as allow for larger starter sizes. I usually end up with 2L as my final stage. If I was using SNS I would need quite a large container and pitch quite a bit of starter wort into my batch. Starters are for growing yeast, that is it. Who cares if the starter wort is nasty? It has no place in your beer unless you are treating the starter like your batch of beer - same wort composition and ferm temp etc... imho.

It is also important to distinguish between a vitality starter and trying to grow a lot of yeast.

 

[cactusgarrett]

Maybe an experiment based on what Maria Moutsoglou (or her paper) actually said, and not on a misunderstanding of her work

I agree with this. Whether true to the original study or not, they ran with (arguably) a more practical approach to the concept and examined what the average garage brewer would do with the info - lower the OG of the starter. There's a lot to unpack with their result and it shouldn't be the end of people looking into it (since despite no discernable difference, the FG was noticeably different). Again - I'm not trying to defend them, just trying not slam the door in their face because of the Brulosophy name alone.

 

[McMullan]

What work/detail on Brulosophy's part would be sufficient for the detractors to this concept consider a shift in their own thinking?

With an attitude expressing blatant anti-science undertones, none, imho. Branding those who offer healthy skepticism and constructive criticism as 'detractors' who should 'consider a shift in their own' beliefs makes me think brulosophy are the last group I want trying to interpret information for me. There's more than enough information disorder online already, thanks.

 

[CascadesBrewer]

I read Denny's page

I would note that the page (and another one or two on their site) are not written by Denny, but by "Saccharomyces". I don't know much about the guy but I have seen several of his posts over on the AHA forums. I suspect there are many with more yeast knowledge than him, but he seems much more qualified than Denny or me on the topic.

While personally, I have had excellent results with SnS starters, with dry yeast and with harvesting yeast to pitch into big beers, I just picked up my first stir plate last week. A stir plate does seem like the best option for building up cell counts.

Oh, great. Brulosophy has now done an experiment based on their misinterpretation of Maria Moutsoglou's comments and/or the paper.

Despite Cade's obvious lack of understanding of the paper, it is a fairly interesting experiment. One thing I have not seen talked here is that Maria's paper claims that they measured better attenuation values with yeast propagated with the low C:N ratio starter than the high C:N ratio starter. This experiment showed better attenuation with the low gravity starter (I am not sure his 5g of yeast nutrient got him to the same C:N ratio as the paper). Note that the paper showed the best attenuation performance came from direct pitching harvested yeast.

I am open to the idea that a larger starter of low gravity wort with added nitrogen might work better than the "standard" 1.040 starter.

Direct link:
https://brulosophy.com/2022/10/24/exbeeriment-impact-yeast-starter-strength-has-on-a-munich-helles/

 

[VikeMan]

I am open to the idea that a larger starter of low gravity wort with added nitrogen might work better than the "standard" 1.040 starter.

Well, yes. That's certainly worth a look, with the emphasis on "larger," i.e. dilute the "standard" volume and gravity starter down to 2P (and add nitrogen), and use the resulting full diluted volume. I think it's the path for further investigation implied by the paper. Alas, it's not what the Brulosophy experiment tried.

Once (if) it's established that it results in higher cell counts, you could then incrementally reduce the volume of the lower grav starter until reaching the break even point as compared to the standard starter. Then you've found the most efficient "per sugar unit weight" way to get to "X" cells.

Then there's the rigorous panel taste testing of the beers made from these starters. Hopefully, nobody would ever jump to the conclusion of "new best practice" without that. Inconceivable!

 

[logdrum]

Interesting, but being Brulosophy, I will wait to see other sources say the same. Personally, I have given up on starters based on cell counts in favor of the Shaken not Stirred method that Denny Conn talked about on a episode of Experimental Brewing. Shaken, not Stirred: The Stir Plate Myth Buster | Experimental Homebrewing Since trying this method six months ago, my stir plate has been on the shelf gathering dust. Have brewed dozen or so beers and the method works, fermentation still takes off like normal and beers fully ferment out, even with lagers.

I too, have moved to the "Shaken Not Stirred" method & honestly, fermentation has taken off much better than the stir plate/crash method.

 

[Bassman2003]

Thanks Cascades, I thought the web page did not look like a "Denny" web page! Anyway, I do not see the two as mutually exclusive. SnS seems like a vitality starter to me which does not create a lot of new cells but wakes up what you do have which results in a fast start. If you pitched a starter from a stir plate at the same point in the cycle one would get fast start times as well. That does not rule anything out from my perspective. Whatever is the best way to get a lot of fresh, healthy yeast cells is the way I want to do it.

I do not understand the need to "get away" from a stir plate. Making the starter is no easier with or without placing your container on the stir plate. If it is more about the quality of the starter wort for direct pitching, then that would at least be a subjective reason

 

[Bassman2003]

I will have a listen to the podcasts later in the week. Always looking for better yeast performance and if just adding some more nutrient helps, then that is easy. Not sure about 1.008 wort, but will have a look.

 

[CascadesBrewer]

SnS seems like a vitality starter to me which does not create a lot of new cells but wakes up what you do have which results in a fast start. If you pitched a starter from a stir plate at the same point in the cycle one would get fast start times as well.

I have been curious about this myself. I suspect you are correct. A smaller starter for a shorter time will likely help to kick start the yeast, and shaken in a big jar or spun on a stir plate likely does not have a huge impact.

I will have a listen to the podcasts later in the week. Always looking for better yeast performance and if just adding some more nutrient helps, then that is easy. Not sure about 1.008 wort, but will have a look.

The paper might be more value than the podcast:
https://onlinelibrary.wiley.com/doi/full/10.1002/jib.621