Yet more evidence that commercial brewers do not mash at 5.2 to 5.6 pH ...

[Silver_Is_Money]

I just re-read the study we've all rapidly learned to first ridicule and then second vehemently hate. Despite what appears to be a poor translation into the King's English, it actually concludes (immediately preceding the conclusion section) that as to both flavor and stability the unacidified beers (the ones with lower nitrogen, wherein the study had determined that mash acidification increases residual nitrogen) came out on the winning side. This appears to me to be what @Robert65 concluded when he proclaimed 5.65 mash pH (as measured at room temp) to have been the key to his finally brewing consistently great beer, and it is my contention that the peer reviewed commercials who mash at 5.2-5.4 pH as measured at mash temperature (an implied 5.5-5.8 pH if measured at room temperature, for which the midpoint just so happens to be pH 5.65) have been there all along.

With respect to taste the beers are close to each other. The ageing intensity of smell and drinking increases parallel to proteolysis, i. e. the increased configuration of free amino nitrogen influences negatively smell and taste of the forced aged beers. Therefore the trial beer „62 °C” performs better as the other beers (Fig. 14). The lower ageing taste is reflected in a higher acceptance of the aged beer. Regarding flavour stability, the beer with the mashing-in temperature of 62 °C without acidification was better as the beers with acidification or reduced mashing-in temperature (58 °C)

Will lastly this "truth" become self evident? (reflecting back to my earlier philosopher Arthur Schopenhauer quote here)

 

[Silver_Is_Money]

It is my understanding that proteolysis is the breakdown or degradation of proteins into amino acids. Protein is built from amino acids, and the amino group is defined or identified by its nitrogen ion. Mash acidification apparently accelerates the liberation (the freeing from its protein bound state) of this amino nitrogen through protein decay, so a measure of increased wort "free amino nitrogen" (no longer bound within the protein molecules) is a sign of said protein decay, and per this study this increased measure of decay correlates to both off flavor and reduced stability.

The interesting thing (presuming here some validity to the studys conclusions) appears to be that once the Wort is fully divorced from the malts and unmalted grains of its origin via lautering run-off, and then subsequently acidified, this protein decay does not appear to occur to nearly the extreme that it does within an acidified mash whereby said grains are fully present.

This seems at least intuitively to make perfect sense, since protein is about 10%-11% by weight for grains, but only about 0.4% to 0.5% of final beer. By weight this is a roughly 6-fold reduction in protein, meaning that the vast majority of the protein stays behind within the now spent grains, and is therefore not as present within the downstream Wort, so acidification at this juncture involves less proteins leading to less potential for proteolysis. I must inject at this juncture that intuition often leads to very bad science. But if the dissertation is true, this reduced protein decay mechanism may explain why mashing at 5.65 pH (as measured at room temperature) and then acidifying later may factually have the potential to lead to better beer.

 

[TheMadKing]

I brewed a Helles Bock yesterday and chose to forgo any acid in the mash. I did add 2g gypsum and 1g calcium chloride and took several pH measuments along the way. I took all pH measurements with a calibrated Milwaukee MW101 at 20C (I cooled my samples in a shot glass in the freezer)

10 minutes into the mash 5.51 @20C

End of mash 5.58 @20C

I added 500mL of Sauergut at 15 minutes into the boil and took another reading which was 5.00 @20C

Flame out pH was 5.10 @20C

Thought you all might find that interesting

Edit: it should be noted that I'm blessed with very soft water with only 24ppm bicarbonate

 

[SteveH aka shetc]

So they run experiments, try to isolate a variable, collect sensory data using a well known testing methodology, and for the most part have a reasonable number of subjects. What have I missed? C'mon you Spurs, I mean it, c'mon [emoji16]

Pretty sure the few outliers are, ahem, not statistically significant in context.

But, I can agree with the above. Most of their audience doesn't care to delve into the intellectual rigour of this thread (or section). And that's fine. But for most of us it's patently insufficient.

 

[TheMadKing]

So they run experiments, try to isolate a variable, collect sensory data using a well known testing methodology, and for the most part have a reasonable number of subjects. What have I missed? C'mon you Spurs, I mean it, c'mon [emoji16]

It's that sensory data I have a problem with.

I would encourage you to look at how a professional sensory panel is used (not a taste preference panel). They are attempting to use taste preference by untrained tasters as being equivalent to detection or non-detection of a specific flavor change.

It doesn't matter how carefully you set up your experiment if you use uncalibrated equipment incorrectly to gather the data from it.

To modify a George Carlin quote:

think about how bad the average persons taste in beer is, now realize that 50% of people are worse than that.

 

[SteveH aka shetc]

They say their preference data is crap. The results are based on the triangle tests.

It's that sensory data I have a problem with.

I would encourage you to look at how a professional sensory panel is used (not a taste preference panel). They are attempting to use taste preference by untrained tasters as being equivalent to detection or non-detection of a specific flavor change.

It doesn't matter how carefully you set up your experiment if you use uncalibrated equipment incorrectly to gather the data from it.

To modify a George Carlin quote:

think about how bad the average persons taste in beer is, now realize that 50% of people are worse than that.

 

[Silver_Is_Money]

In retrospect I shouldn't have mentioned Brulosophy, even in jest, as it is now beginning to sidetrack and/or outright derail things (as conversations about Brulosophy seem to often do on this forum).

I may be the first person to ever side track his own thread.

 

[Qhrumphf]

It is my understanding that proteolysis is the breakdown or degradation of proteins into amino acids. Protein is built from amino acids, and the amino group is defined or identified by its nitrogen ion. Mash acidification apparently accelerates the liberation (the freeing from its protein bound state) of this amino nitrogen through protein decay, so a measure of increased wort "free amino nitrogen" (no longer bound within the protein molecules) is a sign of said protein decay, and per this study this increased measure of decay correlates to both off flavor and reduced stability.

The interesting thing (presuming here some validity to the studys conclusions) appears to be that once the Wort is fully divorced from the malts and unmalted grains of its origin via lautering run-off, and then subsequently acidified, this protein decay does not appear to occur to nearly the extreme that it does within an acidified mash whereby said grains are fully present.

This seems at least intuitively to make perfect sense, since protein is about 10%-11% by weight for grains, but only about 0.4% to 0.5% of final beer. By weight this is a roughly 6-fold reduction in protein, meaning that the vast majority of the protein stays behind within the now spent grains, and is therefore not as present within the downstream Wort, so acidification at this juncture involves less proteins leading to less potential for proteolysis. I must inject at this juncture that intuition often leads to very bad science. But if the dissertation is true, this reduced protein decay mechanism may explain why mashing at 5.65 pH (as measured at room temperature) and then acidifying later may factually have the potential to lead to better beer.

Hmmmm. More bad science intuition here, but as I've tended to prefer a more acidic mash for ease's sake, I wonder if that explains why I've mostly found "yeast nutrient" (ie the broad class of FAN-laden products) unnecessary to harmful where others find their fermentations sluggish without it.

 

[mabrungard]

So they run experiments, try to isolate a variable, collect sensory data using a well known testing methodology, and for the most part have a reasonable number of subjects. What have I missed? C'mon you Spurs, I mean it, c'mon [emoji16]

The real problem with this citizen science is that untrained and unknowing tasters are being tasked with a ‘mystery’.

How can anyone draw a valid conclusion without knowing what the question is nor having the knowledge or training to pick up the characteristic that the study is pursuing?

The only way this methodology produces a valid result is when the characteristic is so blatant that it’s apparent to anyone. Sadly, many of the ‘improvements ‘ that we impose only provide tiny improvements in beer perceptions. That is far too much to ask from an unknowing taster.

 

[Qhrumphf]

The real problem with this citizen science is that untrained and unknowing tasters are being tasked with a ‘mystery’.

How can anyone draw a valid conclusion without knowing what the question is nor having the knowledge or training to pick up the characteristic that the study is pursuing?

The only way this methodology produces a valid result is when the characteristic is so blatant that it’s apparent to anyone. Sadly, many of the ‘improvements ‘ that we impose only provide tiny improvements in beer perceptions. That is far too much to ask from an unknowing taster.

It strikes me as the same general mindset of many homebrewers with imperfect process and resulting flaws: "will it ruin my beer". A process problem is only a problem if the result is so severe to ruin the beer. An off-note is only present if so intense it ruins the beer. And if not, then clearly all is well, at least to them.

 

[hopjuice_71]

One last thought on Brulosophy that people here can consider.. ..or not.. .. then I’ll let the beaten and dead horse lie.

When one asks a question and investigates it, there is always a “resolution” (level of detail) associated with the approach and outcome. For example, you could be asking the question “what effect does diet X have on the health of mice?” You could work towards answering this question on whole organism level (low resolution) or on a molecular level (high resolution), with the level of detail in the desired outcomes of the study dictating the interrogative approaches used. I might argue that a detailed molecular level study has more value, but this is where my personal biases come in. In the case of Brulosophy, their assembly of a sensory panel and particular triangle approach is clearly addressing their question at a low resolution. It only has the potential to pick up gross effects of their tested variable (i.e is it detectably different), not nuanced effects - Brulosophy knows it and we know it - but this feature/bug/issue does not immediately invalidate the question or the approach, as some people seem to think. As @Qhrumphf implied in a couple of posts, it does, however, mean that the experiments are not going to appeal to a certain cross-section of homebrewers who seek more level of detail while there are many homebrewers for which low resolution is appropriate/good enough.

In my opinion, Brulosophy serves a purpose in providing a level of "resolution" to homebrewers who only care, for example, that a pile of kettle trub in the fermenter won't completely ruin their beer.

 

[hopjuice_71]

I just re-read the study we've all rapidly learned to first ridicule and then second vehemently hate. Despite what appears to be a poor translation into the King's English, it actually concludes (immediately preceding the conclusion section) that as to both flavor and stability the unacidified beers (the ones with lower nitrogen, wherein the study had determined that mash acidification increases residual nitrogen) came out on the winning side. This appears to me to be what @Robert65 concluded when he proclaimed 5.65 mash pH (as measured at room temp) to have been the key to his finally brewing consistently great beer, and it is my contention that the peer reviewed commercials who mash at 5.2-5.4 pH as measured at mash temperature (an implied 5.5-5.8 pH if measured at room temperature, for which the midpoint just so happens to be pH 5.65) have been there all along.



Will lastly this "truth" become self evident? (reflecting back to my earlier philosopher Arthur Schopenhauer quote here)

Back to the discussion...

Sorry, didn't mean to seem like I was ridiculing the Reiter article. The writing and organization make it hard to penetrate, but as you say this is possibly a translation issue. It is almost as if this is some kind of pre-print version where it has undergone review but final edits have not been made to it yet (figures at the end of the document, rather than embedded, are tip-off for this). There is bit of an issue with a disconnect between a few, but definitely not all, of the conclusions and the data presented. For example, I think they may have been using viscosity as an indirect measure of b-glucan content, but this is not clearly specified nor was it measured at both lab and large scale. That being said there is useful data in there if one is willing to sit down and interpret it on their own.

 

[Vale71]

Except viscosity does change in the laboratory mashes and is not even measured in the large-scale mashes, so how do they come to the conclusion that beta-glucan content is invariant?
The focus of the study was clearly the effect of biological acidification on beer ageing, I really don't understand why they had to go and present those extremely broad conclusions that are clearly completely unsupported by their data (and in some cases, the available data even contradicts them) thus disqualifying their work.

 

[dmtaylor]

for the most part have a reasonable number of subjects. What have I missed?

*for the most part have a very low number of unqualified testers so as to call into question the usefulness of any result.

[/derail]

 

[bob1852]

*for the most part have a very low number of unqualified testers so as to call into question the usefulness of any result.

[/derail]

His most interesting write up is how the results aren't much different when he segregates by different experience/expertise tasters...

I think that highlights a huge issue....many more people think they're expert tasters than actually are, and things like BJCP level aren't a great way to tease that out.

 

[hopjuice_71]

Except viscosity does change in the laboratory mashes and is not even measured in the large-scale mashes, so how do they come to the conclusion that beta-glucan content is invariant?
The focus of the study was clearly the effect of biological acidification on beer ageing, I really don't understand why they had to go and present those extremely broad conclusions that are clearly completely unsupported by their data (and in some cases, the available data even contradicts them) thus disqualifying their work.

Honestly, I am only guessing about the b-glucan thing... ...it really wasn't clear.

We could go really deep down the rabbit hole regarding the underbelly of science, the flaws of the peer-review system, issues with publishers, and how the media deals with science. Suffice it to say, overstatement is rampant in science. Sometimes it escapes reviewers and editors. I have even seen it encourage by journal editors! At the end of the day, it is really up to the reader to use the data as they see fit. This article has data that can be interpreted without really caring what conclusions the authors have articulated.

 

[hopjuice_71]

*for the most part have a very low number of unqualified testers so as to call into question the usefulness of any result.

[/derail]

Here is how I see this issue. Say I gave you two nearly identical pictures of a person and asked you to pick out the difference(s). If the difference was a very minor alteration to an eyebrow, you might have a very hard time finding it. If I pre-trained you to focus on facial features (i.e. "qualified" you) your chances of finding it would increase greatly. However, if the difference was that in one picture the person was missing a leg, or both legs, the difference would be obvious to the trained or untrained, or even if you were an alien that had no idea what a person was supposed to look like. You can expand this analogy to a panel looking for differences in the pictures.

If you view Brulosophy through this lens, the qualifications of tasters become irrelevant. All we have to understand is that the experiments will only reveal major differences. This may or may not be useful to you, but it may be to others.

Guess i didn't let the dead horse lie. Sorry, its just an interesting discussion.

 

[Qhrumphf]

I think the crux is that Brulosophy has their setup in such a way that only major differences will be identified. And as such it appeals to the low standard of proof "anyone could identify it" or "will it ruin my beer" bar that most homebrewers will be happy with. The "Joe Six-Pack not bad beer" standard. To that extent, nothing wrong with it as long as those limitations are acknowledged. And higher levels of brewing science on this section (along with LOB and the like) tend more into not only subtleties of character, but the stability of such. These are things that generally matter to pros to which higher level brewing science is directed, and only a small minority of homebrewers.

 

[bob1852]

To that extent, nothing wrong with it as long as those limitations are acknowledged.

They do acknowledge that.

It's not their fault that some of their readers do not.

 

[Qhrumphf]

They do acknowledge that.

It's not their fault that some of their readers do not.

I've never faulted Brulosophy directly. I've always found them very fair and open of their limitations. Their readers not so much...

 

[bob1852]

I've never faulted Brulosophy directly. I've always found them very fair and open of their limitations. Their readers not so much...

Yep, your critiques of their approach have always been fair and mathematically/scientific method based...

Some others, not so much...

 

[enkamania]

So I'll go with a 30 minute acid addition. I only do 30 minute boils. Before, I was just finding a time prior to whirfloc that I wasn't "busy"

 

[mabrungard]

Even with a pre-disclosure of what the study’s characteristic might be, untrained evaluators might not pick up a difference. But I still think that this WOULD help an evaluator pick out the odd beer instead of them guessing if there’s any difference at all.

A case in point, last night I was enjoying a good rauchbier that had a minor tannin problem. One of my friends was enjoying the beer and said it was perfect until I pointed out that minor issue. After that, he admitted that it was there.

A suggestion of a possible problem doesn’t increase or decrease a false sense of perception when you include a comparator beer that doesn’t have the problem.

 

[hopjuice_71]

With respect, I am not sure your example is necessarily the best one. Under the conditions you describe - where you pointed out the flaw was there and the exact identity of the flaw - you introduced a massive bias. Of course your friend would find it. I have a terrible palate and I probably would have found it, even if it was entirely in my head

The intention of your point is well taken though, and I find that you are actually supporting the points made regarding the panel tasting. The distinction is where the intended threshold of detection by the panel lies. There is no question that training/priming evaluators would increase sensitivity, but the point is that the Brulosophy panel method is not aimed at detecting minor or subtle, it seems designed by purpose to detect the obvious (as for the why, see post #228 by @Qhrumphf - summed up well there). When you think about it, if detecting the obvious is the goal, then a panel of unqualified "Joe-six-pack " drinkers is exactly what you'd need.

 

[bob1852]

But I still think that this WOULD help an evaluator pick out the odd beer instead of them guessing if there’s any difference at all.

But, the purpose of a triangle test isn't to help the evaluator pick out the odd sample. The null hypothesis is that there isn't a detectable difference between the samples.

If they don't know what to look for, and can't reliably detect the difference, that's really the whole point of a triangle test.

If I gave you three cookies, and said "tell me which one was made with brown sugar, as the other two were made with white sugar", that defeats the purpose of a triangle test. If I say "tell me which of the cookies are different?" and the panel can't reliably do that (to what ever P level you seem important enough), you can then conclude that making your cookies with either brown or white sugar doesn't really matter.

I still think there's a fundamental misunderstanding to what a triangle test is supposed to accomplish....

 

[Robert65]

I still think there's a fundamental misunderstanding to what a triangle test is supposed to accomplish....

I've seen this with another popular experimental brewing site, though I won't name names... Often the fact that tasters show no *preference* is taken as indicating there is no significant *effect* attributable to the difference in methods being compared, where no preference is mistaken for meaning there is no perceivable difference. This also creeps into Brulosophy from time to time in their discussion, but they at least usually do note the distinction, which may be appropriate if their goal is to sort out differences that will really matter to Joe Sixpack.

 

[bob1852]

I've seen this with another popular experimental brewing site, though I won't name names... Often the fact that tasters show no *preference* is taken as indicating there is no significant *effect* attributable to the difference in methods being compared, where no preference is mistaken for meaning there is no perceivable difference. This also creeps into Brulosophy from time to time in their discussion, but they at least usually do note the distinction, which may be appropriate if their goal is to sort out differences that will really matter to Joe Sixpack.

Yeah, I wish they'd do away with the post-triangle test preference question.

The purpose of the experiment isn't about preference, it's about detectability of difference.

If they want to do taste preferences of a variable, the triangle test is the wrong test.

 

[Silver_Is_Money]

Indeed Brulosophy has now completely derailed this thread.

 

[day_trippr]

"When that happens, one must consider whether the thread had run its course"

[Some Wise Guy]

 

[Robert65]

The derail has at least illustrated the different levels of significance of actual, measurable effects of changes in process, and suggests which categories mash pH prediction/control and simple kettle pH adjustment may fall into. I would venture that the effects of the latter would be more likely to be detected by, and even important to, even our new friend Joe Sixpack. There you go, topic reintegrated.