Fundamental shift in yeast starter preparation?

[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

 

[VikeMan]

I will have a listen to the podcasts later in the week.

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

I would skip the podcast(s) and go right to the paper. The podcasters claim some numbers and concepts not supported by the paper.

 

[onlyhere4science]

Maria Moutsoglou addresses the cost for inclusion of yeast extract for nitrogen vs. using full strength wort for prop media here. Sounds like because you're using less DME/wort sugars, it's more cost-effective to produce cells with low OG/high nitrogen vs. standard wort. So the cost comments here are kinda off imo.

Lest we forget that The Journal of the Institute of Brewing is peer-reviewed and David Quain is the editor. So there is fact checking done on the work itself.

 

[VikeMan]

Maria Moutsoglou addresses the cost for inclusion of yeast extract for nitrogen vs. using full strength wort for prop media here. Sounds like because you're using less DME/wort sugars, it's more cost-effective to produce cells with low OG/high nitrogen vs. standard wort. So the cost comments here are kinda off imo.

The paper we've been discussing, i.e. this one...

https://onlinelibrary.wiley.com/doi/full/10.1002/jib.621
...does support that low (2P) gravity starter worts (with adequate nitrogen) are more cost effective, i.e. produce more cells per unit weight of sugar, and I have no problem with that. The problem I see is that podcasters seem to have misinterpreted the data and led people to believe that a 2P starter of a certain volume will produce as many or more cells than an 8P (or 9P or 10P) starter of the same volume, which the data doesn't support.

 

[onlyhere4science]

The paper we've been discussing, i.e. this one...

https://onlinelibrary.wiley.com/doi/full/10.1002/jib.621
...does support that low (2P) gravity starter worts (with adequate nitrogen) are more cost effective, i.e. produce more cells per unit weight of sugar, and I have no problem with that. The problem I see is that podcasters seem to have misinterpreted the data and led people to believe that a 2P starter of a certain volume will produce as many or more cells than an 8P (or 9P or 10P) starter of the same volume, which the data doesn't support.

You're right - you don't make as many cells by volume with a lower P media at least with the conditions used in the paper. So yes...you make more physiologically ****** cells with high OG.

Just for data sake, actual numbers numbers from the paper are in the Supporting Info. If we compare H5 which is plain wort/no additional nitrogen (e.g., standard brewing prop media), peak cell counts were 42.1 x 10^7 cells/mL. Peak cell count for L1 (2P, high nitrogen) was 30.1 x10^7 cells/mL. Copied the table below for reference.

Table S7. Properties of S. cerevisiae growth profiles in YCM or wort with high (H) or low (L) C:N ratio. Significance established against YCM, where significance is designated by * p ≤ 0.05, ** p ≤ 0.005, and *** p ≤ 0.0005 (α = 0.05).

Media Identifier​	Number of Growth Profiles​	% Viability a​	pH b​	​	% Ethanol (v/v) b​	Total Cells Produced (x 107 cells/mL) c​
YCM​	3​	99.0 ± 0.1​	5.08 ± 0.05​	​	0.89 ± 0.02​	26.8 ± 2.3​
H1​	2​	99.1 ± 0.3​	3.30 ± 0.04***​	​	0.88 ± 0.05​	17.2 ± 2.3*​
H2​	2​	98.1 ± 0.4*​	3.35 ± 0.01***​	​	1.76 ± 0.06**​	27.3 ± 1.7​
H3​	2​	98.9 ± 0.7​	3.45 ± 0.03***​	​	2.80 ± 0.21**​	32.8 ± 3.2​
H4​	2​	98.3 ± 0.4​	3.56 ± 0.08***​	​	3.80 ± 0.03***​	47.0 ± 0.5**​
H5​	2​	98.7 ± 0.3​	3.71 ± 0.06***​	​	5.24 ± 0.08***​	42.1 ± 0.1**​
L1​	3​	98.6 ± 0.1*​	4.99 ± 0.02​	​	0.68 ± 0.06*​	30.1 ± 5.3​
L2​	2​	97.5 ± 3.2​	4.85 ± 0.09*​	​	1.89 ± 0.01***​	33.7 ± 4.5​
L3​	2​	97.6 ± 3.4​	4.63 ± 0.03**​	​	3.06 ± 0.00***​	31.5 ± 1.7*​
L4​	2​	98.7 ± 1.6​	4.69 ± 0.00**​	​	3.96 ± 0.05***​	36.9 ± 5.9​
L5​	2​	99.0 ± 0.6​	4.74 ± 0.05**​	​	5.03 ± 0.06***​	38.4 ± 0.9**​
aAverage and S.D. for yeast in stationary phase. bAverage and S.D. of pH obtained from samples collected for fermentation efficiency analysis (n = 2) at the completion of growth. cDifference between average of four stationary phase cell concentrations and initial cell concentration for each growth profile.

 

[McMullan]

Lest we forget that The Journal of the Institute of Brewing is peer-reviewed and David Quain is the editor. So there is fact checking done on the work itself.

Not really. Peer review is more about 'Is this research publishable?'. Fact checking is more about independent confirmation either by reviewing existing data in the literature, if there are any, repeating experiments and/or designing new experiments to challenge the hypothesis. Oddly, assuming we start with sufficient healthy yeast cells, 1.040 wort starters work just fine, regardless whether they're stirred, shaken or just left in a cupboard. My fermentations proceed at a respectable rate and attenuate to around 80% -/+ a couple points. I'm not sure what needs to be fixed, tbh. Perhaps the research - if confirmed - is of more interest to some large commercial breweries struggling to propagate sufficient yeast (within budget) due to scale. At home-brew scale the 1.040 starter has been confirmed over and over. Seems a bit odd, to me, to be diluting starter wort therefore available nitrogen then adding nitrogen. I don't expect to see any significant improvements for home brewers.

 

[onlyhere4science]

Not really. Peer review is more about 'Is this research publishable?'. Fact checking is more about independent confirmation either by reviewing existing data in the literature, if there are any, repeating experiments and/or designing new experiments to challenge the hypothesis. Oddly, assuming we start with sufficient healthy yeast cells, 1.040 wort starters work just fine, regardless whether they're stirred, shaken or just left in a cupboard. My fermentations proceed at a respectable rate and attenuate to around 80% -/+ a couple points. I'm not sure what needs to be fixed, tbh. Perhaps the research - if confirmed - is of more interest to some large commercial breweries struggling to propagate sufficient yeast (within budget) due to scale. At home-brew scale the 1.040 starter has been confirmed over and over. Seems a bit odd, to me, to be diluting starter wort therefore available nitrogen then adding nitrogen. I don't expect to see any significant improvements for home brewers.

If you do what you've always done, you'll get what you've always got. Seems like a common mindset in home brews and commercial brewers, which is fine. No one can argue there is anything wrong with respectable rates and respectable attenuations. On the other hand, there are those that may see the opportunity in innovation that leads them to discovery and success that fuels their home brewing passion.

The paper cites other peer-reviewed research that dips into Crabtree regulation of brewing yeast effect. It's not like the research re-invented the wheel, it simply applied a known theory in a practical way for brewers to employ. And it would be kickass to see more research that jumps off from the paper's starting point...kinda like what Brulosophy did. More peer-reviewed work would be even better. Healthy skepticism is key to the scientific pursuit, probably how this research came along in the first place.

I'm just happy people are talking about yeast tbh.

 

[sibelman]

The reduced-gravity starter idea is somewhat intriguing. The expression "500% less" is frankly hilarious.

Does the speaker perhaps mean "reduced to 1/5th of the original amount", which would be 80% less? If so, it's a very odd way to say it.

 

[VikeMan]

Does the speaker perhaps mean "reduced to 1/5th of the original amount", which would be 80% less? If so, it's a very odd way to say it.

I'd say It doesn't really matter, as that wasn't true anyway. I would be nice, but probably wishful thinking, if "everyone" would read and understand the paper. It would be a lot easier to discuss.

 

[Bassman2003]

I listened to the podcast in my car and it is quite interesting. The Dr. is well spoken and explains everything quite clearly in brewing terms. My only question is about the dilution/starter volume. She mentions taking 13P wort and diluting down to 2P but I can not find much information about volumes. Looking at the table above it seems everything was at the same volume so the 2P wort was very efficient in making cells for the amount of ingredients. But, at comparable volumes, it made fewer cells than the 13P wort. So that would lead me to think to beat the 13P wort in cell count, one would need to almost double the volume of the 2P wort. Is this correct?

While this might save larger breweries money but at our scale, making larger starters is not very practical. I make 2L starters with 1.040 wort. If I am going to employ this method it seems I would need to make 3-4L starters to actually make more cells. While the high Nitro starters create healthy cells, I do not see the aspect of under pitching appealing. I still want to create/pitch the correct number of cells. Please let me know if I am off base as scientific papers seem a bit overwhelming to me at times.

 

[onlyhere4science]

I listened to the podcast in my car and it is quite interesting. The Dr. is well spoken and explains everything quite clearly in brewing terms. My only question is about the dilution/starter volume. She mentions taking 13P wort and diluting down to 2P but I can not find much information about volumes. Looking at the table above it seems everything was at the same volume so the 2P wort was very efficient in making cells for the amount of ingredients. But, at comparable volumes, it made fewer cells than the 13P wort. So that would lead me to think to beat the 13P wort in cell count, one would need to almost double the volume of the 2P wort. Is this correct?

While this might save larger breweries money but at our scale, making larger starters is not very practical. I make 2L starters with 1.040 wort. If I am going to employ this method it seems I would need to make 3-4L starters to actually make more cells. While the high Nitro starters create healthy cells, I do not see the aspect of under pitching appealing. I still want to create/pitch the correct number of cells. Please let me know if I am off base as scientific papers seem a bit overwhelming to me at times.

A fair question for sure. Seems like there was still p good growth in the 2P recipe, but certainly lower than an 8P recipe from the example provided in the table above. I think the quote from the paper below is interesting but def applies more to commercial brewers:

The total cell count in low C:N wort with 2°P sugar was 301 ± 53 x 106 cells/mL (Table S7). For a standard wort (13°P) and a pitching rate of 6.5 x106 cells/mL, the target inoculum could be met with a 2% (v/v) transfer. This is markedly more efficient than the common brewery scale-up strategy that uses a 10% or more (v/v) transfer (14).

It seems like you might suggest there is a benefit to pitching a higher quantity of physiologically unhealthy/lower vitality cells vs. a lower concentration of physiologically vital cells. In this case, around 28% fewer cells would be pitched with a 2P recipe of "same volume." I would bet the tradeoff is not exactly linear, but this would be something to test for sure!

 

[Bassman2003]

Thanks for your reply. In my mind, the best case scenario is pitching a high quantity of physiologically vital cells. I also wonder about the middle ground. While the research shows higher sugar inhibits ATP production and makes the environment less conducive for growth, does just adding more nitrogen to a 13P wort show any benefits? What about higher nitrogen but 6P wort? etc...

 

[onlyhere4science]

Thanks for your reply. In my mind, the best case scenario is pitching a high quantity of physiologically vital cells. I also wonder about the middle ground. While the research shows higher sugar inhibits ATP production and makes the environment less conducive for growth, does just adding more nitrogen to a 13P wort show any benefits? What about higher nitrogen but 6P wort? etc...

Anytime dude. Agreed on your thoughts on best case scenario.

Paper shows results with a good range of OGs with and without nitrogen. It’s my understanding that adding nitrogen in the prop media regardless of OG had a benefit - last graph shows that attenuation was improved for all OG when nitrogen was added. Sounds like there is likely a middle ground or at least an opportunity to improve your yeast health w nitrogen/yeast extract while still meeting a pitch rate target.

 

[Bassman2003]

When I grow up yeast, I start with a frozen 50ml vial. Go to 250ml of wort then ~2L. I pressure can my wort so I make a single mason jar with double strength wort and dilute with water. So I am seeing some opportunity to increase the dilution a bit as well as increasing yeast nutrient. While my container is limited to ~3L, I could probably add some more water and a little less wort. This is with an assumption that the C:N ratio has a linear application from high to low.

 

[McMullan]

I skimmed over the paper (methods and results). I wasn't that impressed. Very limited data with a lot of variation. Probably even more if the experiments were done more than only twice. I'd expect triplicate experiments at least, in a design submitted for publication rather than a look-see. All research needs to be confirmed independently and this research is definitely no exception. What puzzles me, though, is the initial steps in brewery yeast propagation usually use about 2P agar/media with yeast extract and peptone. In my case, when starting from scratch using stored/frozen yeast, there's an initial overnight 10ml prep that gets streaked on agar plates for QC and selection of healthy looking colonies, which go in another 10ml prep for 48 hours before getting stepped up to 100ml for another 48h. Then it's time to step up using 500ml 13P/1.040 starter wort with yeast nutrients. Subsequent step-ups, usually 2.5L then a half batch (12L) beer to full batch, are repitchings, in my mind, at home-brew scale.

As the link between yeast quality and fermentation performance has been established(5, 6), propagation must yield viable, physiologically ‘tuned’ yeast for serial repitching or for single use fermentation.

The best way to 'tune' brewer's yeast - to condition them metabolically against the stresses of fermentation environments and be fit for repitching is to pitch them into brewery wort. This has been known for decades. The cells develop a metabolic 'memory' of the fermentation environment, which is what we want. Once through the initial (millilitres) propagation steps yeast are ready for 13P/1.040 wort, with more than enough biomass production to harvest and repitch for optimised fermentations. For home brewers and micro breweries there is little to be gained in getting bogged down with yeast propagation practices optimised for large-scale brewing operations.

But it wouldn't surprise me if at some point 'Proper Starter 2(P)' hits the home-brew market. Imagine for a moment, a place where cans of unfermented wort - weak or not - actually sell for more than cans of beer. A new definition of being hoodwinked?

 

[madscientist451]

I'll go out on a limb here and predict that at the homebrew level, if you made two starters, one with my lazy-ass no oxygen, no nutrient no stirplate, 10.040-ish wort, jug with an airlock method and the other starter with the complicated method discussed here, that you won't be able to tell the difference in the beer at the end.
Or did has someone already test it out? The x-beeriment linked above didn't do the step feeding but did start with a low gravity wort.

Edit: Since I'm also kind of a cheapscate, if I can use less DME in a starter and the beer comes out the same, why not do that?
Yeah, I'm really not saving much money, and there's no way I'm going to fuss with step feeding a yeast starter.

 

[VikeMan]

Thanks for your reply. In my mind, the best case scenario is pitching a high quantity of physiologically vital cells. I also wonder about the middle ground. While the research shows higher sugar inhibits ATP production and makes the environment less conducive for growth, does just adding more nitrogen to a 13P wort show any benefits? What about higher nitrogen but 6P wort? etc...

In the paper's data, there's a little bit of a middle ground. See Figure 2-B. Under the conditions tested, the efficiency per gram of sugar benefit for low C:N wort was highest at 2P, and broke even with high C:N wort at roughly 4.5P. Any higher, and the low C:N wort was actually less efficient than the high C:N wort.

The reason for the highest per gram of sugar efficiency at 2P was believed to be due to suppression of the Crabtree effect (and I'd bet a paycheck that it was). You can see the same phenomenon in the high C:N wort, but it's not as dramatic, with the relatively lower nitrogen content being the likely reason for the impact being less pronounced.

Maybe someone will test "large volume, low gravity" starters vs. "low volume, high gravity" starters (both with adequate nitrogen), with the relative volumes calibrated to produce the same number of cells. And then make beer from these starters, and taste test panel the beejezus out of them, because all of this isn't very useful if the beer doesn't improve, or at least maintain the same quality at a lower cost.

Also, a thing that gives me pause is that the paper touted lower residual sugars as a de facto benefit of beers made with the yeast from low C:N starters, even calling the beers made with the yeast from high C:N starters "under attenuated." To me, under attenuated means attenuated less than the brewer intended. We have many knobs in recipe and process to influence attenuation. If we have styles/recipes that have evolved to get certain levels of attenuation from traditionally produced yeast, why would attenuating the same beer further be assumed to be an improvement? Everything gets a little drier and we therefore love it?

 

[RM-MN]

Edit: Since I'm also kind of a cheapscate, if I can use less DME in a starter and the beer comes out the same, why not do that?

Gordon Strong has reported that the often makes lagers and just pitches a single smack pack. Being a 4 time Ninkasi winner, he should know what beer should taste like. How does he get by without making a starter? You can't get much cheaper on starters than not making one.

 

[McMullan]

why would attenuating the same beer further be assumed to be an improvement?

From a big/macro brewery's perspective? It translates into more ethanol therefore more beer. More product per run of the brewery. They can use various tricks to maintain consistency of the brewery's products. Like a lot of research focusing on commercial challenges, e.g., high gravity brewing, it's about increasing profits and not necessarily of much use being applied at the nano scales associated with home brewing. I'd guess most home brewers don't even bother to propagate yeast before pitching into FV wort.

 

[Bassman2003]

Thanks for the discussion. The split between home and pro is often around money/profit. I am more interested in the increased performance of the yeast compared to saving money or lower plato wort. I think the use of the term under attenuated was in the context of expected attenuation compared to actual. I think we all want yeast that kicks ass. We can adjust our process around any yeast behavior, but if we can get them to perform optimally, then all the better.

One could put all of this into 'ain't broke, don't fix it' category, but that is the exact reason the research was done - for the pro brewers. They want to push the cost savings so they are looking for ways to improve process.

I see the overall premise as valid - to build up very potent yeast cells to then handle the stressful environment of fermentation. Do you go to bed early, pre-hydrate and rest up before a big event or keep your routine the same? It is easy enough to add some more nutrient and dilute some wort so I might try this to some extent. But the real determinant for me is better attenuation/performance and flavor consistency not biomass imho.

 

[VikeMan]

I think the use of the term under attenuated was in the context of expected attenuation compared to actual.

Maybe. But then, what was the expectation, and what was it based on? It's would be kind of odd to get less attenuation than normal, using the standard process on which the expectation was based, and then call it out as a shortcoming of the process.

I think they called it "under attenuated" because it was less attenuated than the attenuation they got from the non-typical process.