A Dry Yeast Rehydration Experiment

It would be even nicer if they would (using your number) say "there is a 92% chance the panel detected a real difference." Instead, we get "these results suggest tasters in this xBmt were unable to reliably distinguish..."

If there were 100 different experiments with this same result, we should know that in the overwhelming majority of them, a difference was in fact detected. (As an aside, n > 1 could find the true "no difference to the average Joe" processes/ingredients.) But the way the results are presented feeds the lazy "nothing matters" trend in homebrewing. </rant> <!-- for now -->

 

Obviously I was not responding to dmtaylor's response. And of course I agree with him and was suggesting that there might indeed be a difference. Not only that, I was suggesting that the test itself was not conducted carefully enough, and could have shown even more difference.

As for the test itself, it doesn't take much crtitical thinking. Even without using statistical methods (using varying confidence levels, whether 95% or 91.7%), it's obvious that with three samples, if they were only randomly chosen, only 1/3 of the participants (8.7) would have chosen the correct sample. Instead, 12 picked the correct (different) sample, which is obviously significant.

What was also significant, however, and disturbing, is that out of the 12 tasters who correctly chose the sample that was different, 11 of them incorrectly chose the warm fermented beer as the one they thought was fermented cool.

 

This might sound terrible, but it's consistent with my sense of humor:

I'm glad to see that you're disturbed. Too many people are not disturbed.

 

Amen Brutha. But it's not obvious to everyone, and my guess is that it's not obvious to most. I think more people see something like 12 out of 26 tasters correctly choosing the unique sample, and thinking "Gosh, less than half of the tasters got it right. There must not be a difference." I base this opinion on the plethora of posts on this and other forums using the results as evidence to support the "nothing matters" flavor of the day. It's the wackiest form of confirmation bias, because it's not even confirmation.

 

I couldn't agree more. But I think that statistical evaluation is beyond most people's grasp, so they immediately ignore the statistics and jump to the author's conclusions, whether or not his evaluation was correct. As I pointed out, one doesn't even need to have a statistical background to see the obvious. Early High School math (simple division) should be more than sufficient.

The real question remains - out of the 12, why was it that almost all of them chose the warmly fermented beer as the cool fermented beer?

Thus again, my speculation that the differences may be 'more' related to the relative amount of healthy yeast action, than the fermentation temperature. In other words, by using the same amount of yeast in a warmly fermented beer as in a beer fermented significantly cooler, it is likely that the warmly fermented beer had a proper amount of robust yeast - at least very significantly more so than the cool fermented beer. The cool fermented beer may therefore have had an improper amount of yeast. As we know from experience, and as many have constantly claimed, even professionals, not providing a proper amount of healthy yeast to a beer, especially a lager fermented at lower temperatures, produces an inferior product.

Thus when the tasters in the experiment tried to select the beer that was fermented at a cooler temperature (therefore likely consciously selecting the beer that tasted better, based on preconception), they chose the beer that did come out superior, based on healthier yeast dosing.

So, to improve the experiment, at least in one respect, I think it would be more proper to provide more yeast to the cooler fermented beer than the warmer fermented beer. In other words, I think that both beers should have the proper amount of yeast for that fermentation temperature, not the same amount of yeast.

 

I believe you are exactly right. Hit the nail on the head. But, we might be wrong. More exbeeriments are needed. ;D

Personally, I've begun fermenting my lagers warmer, as I hinted previously, the reason being that I hypothesize that there's little if any downside and that the so-called estery profile of a lager yeast doesn't kick in at low 60s F but might do so at unusually high temperatures in the 70s or above...... which is exactly the same as the guidance I would give anyone about the average ale yeast! There are always some exceptions to any rule, but in general, I believe this to be true. But again, of course, more exbeeriments are needed.

 

I have only a limited education in statistics, so I am a little out of my depth here. But I think the problem is not just that a p-value of 0.05 is arbitrary. The problem is that negative results are reported in a way that has proven to be highly misleading to the casual reader. (VikeMan has been hammering this point for a long time.) In a lawyerly sense, it's not technically false to say something like "participants in the experiment were unable to reliably tell the difference." That merely restates the experimental results. But most readers probably assume that this negative result has "external validity" (meaning it's predictive of what you would expect to happen if you brewed the beer in the real world), which is not always true. You'll see people on this forum reporting negative results as if it establishes that the practice being tested doesn't matter, and this is not generally warranted.

So in short I think it's bad to mislead people and I wish Brülosophy would stop doing it. The gap between the respect the site purports to have for its readers and the respect that it actually pays them is troubling.

 

I totally agree, but have you expressed your concern directly to Marshall Schott?

 

What difference would that make? Marshall can accept constant criticism, as meanwhile he is supported by millions, so he can choose to absorb as much or as little as he wants. Celebrity status. As long as he is never accused of sexual harrassment or racism, he'll continue to be adored by the masses.

Don't get me wrong, I like Marshall a lot, he's a very decent guy. It's just... he doesn't know us from Adam, and he's bombarded, so... yeah... why... what difference......

 

I've left comments from time to time but I haven't communicated more directly than that. I don't take a completely cynical view—I don't think he's consciously trying to mislead people—but at some point ignoring these issues starts to look like willful blindness. It's too bad because as dmtaylor observed, he seems like a decent enough guy, but as I've come to understand how bad the site's statistics are (as I said, I don't have a lot of statistics education, so it took me a while), I've grown less patient. At this point I might even say the site is on net detrimental to the hobby. Maybe not, maybe I'm overstating how much people rely on purported negative results, but the fact that it's even a question says there's a real problem.

 

I very much agree, and I have been openly saying this is poor ( I use the term "hot garbage", but I digress) for many years..

However, Marshall and his "team" will not pay the slightest mind to the naysayers. This is a VERY lucrative business model for them, and the sheeple way out-way the shepards. Plus, I think they strongly believe (dare I say, confirmation bias?) they are doing the community well.

At the end of the day though, I really don't care. I don't have the drink their or anyone who follows there short and shoddy practices beer. Its all "fake news" to me and I move on.

If you are indeed keen on real brewing science, I suggest https://brewingscience.de and the MBAA.

 

Yeah, I can feel your frustration. I haven't really read too many of his experiments, so was not aware of the issues until today. I've always been of the belief that if something important doesn't seem right, then it's better to speak up and complain, than to let it ride (I've done my share of this, writing to various sites, breweries, etc., but most often with no response). Otherwise, nothing in this world will ever get better. I guess the question is, how 'important' is this? From the perspective of a hobby where newbies are involved (we're all 'newbies' to some aspect of brewing), I always found many of the people in BA going out of their way to help others avoid some of the pitfalls and myths surrounding this hobby. So, perhaps, just speaking up about it in these forums, like so many have, is more than sufficient. If some people prefer to go to one or two single sources for all their gospel understandings about brewing, and never question what is said, then it's their own intended misfortune.

 

Brulosophy permits folks to comment to the various exBEERiments. Why not place your comment about the need to 'adjust' yeast amounts between cold (50 degrees F) and warm (70 degrees F) there:

http://brulosophy.com/2016/02/08/fe...ager-yeast-saflager-3470-exbeeriment-results/

Cheers!

 

I did go there and actually started including my comments, but then decided that I should first look into it a little more deeply, before I could respond more clearly. I have written comments to many similar sites in the past (including one just this last week or two), but I rarely get a response. It's human nature that positive suggestions are often viewed as negative criticisms. As @dmtaylor and @minderbender stated above, it might do little good. But I guess it never hurts to try.

In order to respond properly, I have to convince Marshall Schott that he may not have provided a sufficient amount of yeast in the lager. He provided a photograph of the package, which suggests that one package is enough (he used two). We both now know that the instructions on the Fermentis lager packages are incorrect (admitted by Fermentis and corresponding to their detailed sheets) and that double the amount needs to be used. We also know that even this amount is intended only for the 'preferred' temperature range, rather than for the entire possible range (Schott went below the preferred range for his lager). Thus he likely strongly believes that he pitched enough yeast in the lager, in contradiction of what Fermentis actually suggests in their detailed documentation. This will become a key part of the response.

 

I should also mention that I'm currently brewing a lager, also at 50 F, and using two packages of Fermentis lager yeast (S-189). The fermentation took two days to start, and is still fermenting today, 13 days after pitching. Thus it's obvious (to me, and according to the detailed specifications) that two packages (they were quite new) were not enough, and I will likely end up with an inferior product.

 

Based upon the numerous posts you have already made why not one more post at Brulosophy?

Cheers!

 

Did you rehydrate those two sachets (using the specific Fermentis directions)?

Cheers!