Furthering Your Beer Education

My suggestion is to buy some advanced brewing science books.

http://www.mbaa.com/store/Pages/atoz.aspx

 

You may already be aware of this site but permit me to suggest you follow: http://brulosophy.com/exbeeriments/

Cheers!

 

Woo-Hoo!

Cheers!

 

I'd be careful about drawing any conclusions from them. Each one (at least the ones I've read) has not been repeated, so n=1. And even if they were to be repeated and verified, I'd think long and hard before applying results more broadly, e.g. to other styles, or to beers produced under other conditions (i.e. with other combinations of processes not being tested).

 

Heretic!

The so called Brulosopher experiments are the certified truth because they are published on some dude's blog. Wait...

 

This critique is very much like Angus Deaton's critique of randomized controlled trials in development economics (PDF). Deaton just won a Nobel, by the way.

 

As an actual economist, I can say with certainty that he did not get a nobel for that crappy argument

With that said, I agree with @VikeMan. I would not change my brewing practices based on the really small sample sizes in the experiments on that site. They are fun to read and are often food for thought, but he needs to get at least 50 people to have a hope of detecting a real difference between brewing methods.

 

I think this comes down to the question of how far you can extrapolate from a randomized controlled trial. Here is an experiment from Brülosophy on mash temperature. The grain was mashed at either 147°F or 161°F, and the rest of the brewing process was designed to be identical. The high-temperature mash resulted in a much higher final gravity (1.014 vs. 1.005), but in general people couldn't tell the difference between the beers by sensory analysis, and those who could tell the difference couldn't tell which one had been mashed hotter. On the other hand, the hot-mashed beer generally got higher marks for mouthfeel and aroma.

With an experiment like this, we might ask how much internal and external validity we have achieved. Internal validity refers to the repeatability of the experiment (as well as other factors that might undermine its causal explanation for the observations). Under the exact same conditions, should we expect the same results? I think everyone is on the same page that a small, unrepeated experiment like this has questionable internal validity.

External validity refers to how applicable the results are to different circumstances. Deaton questions the external validity of RCTs in development economics (he also questions their internal validity, but that's not our topic here). Sample quotation:

Yet I also believe that RCTs of "what works," even when done without error or contamination, are unlikely to be helpful for policy unless they tell us something about why it works, something to which they are often neither targeted nor well-suited.... Actual policy is always likely to be different from the experiment, for example because there are general equilibrium effects that operate on a large scale that are absent in a pilot, or because the outcomes are different when everyone is covered by the treatment rather than just a selected group of experimental subjects. Small development projects that help a few villagers or a few villages may not attract the attention of corrupt public officials because it is not worth their while to undermine or exploit them, yet they would do so as soon as any attempt were made to scale up. The scientists who run the experiments are likely to do so more carefully and conscientiously than would the bureaucrats in charge of a full scale operation. So that there is no guarantee that the policy tested by the RCT will have the same effects as in the trial, even on the subjects included in the trial.... [A]n educational protocol that was successful when randomized across villages in India holds many things constant that would not be constant if the program were transported to Guatemala or Vietnam.​

I'm a little surprised that @wspscott thinks this is a crappy argument. I don't detect any crappiness in it. As I said, it is a lot like @VikeMan's argument about whether a Brülosophy result will hold true when it is applied to a different beer style, or a different brewing process. If anything, I would say Deaton's argument is more solid, because at least in brewing there is a known physical/chemical process underlying the results, so we have a better (if imperfect) conception of what the relevant variables are. (The big variable that I think we have a quite poor understanding of is the tasting environment—give me the same beer on different days, and I might have very different reactions, based on who knows what.)

To keep the discussion beer-focused, let's give an example. We could draw the following conclusions from the mash temperature experiment described above. Here they are, in decreasing order of implied external validity:

1. A hot mash leads to a higher final gravity and better mouthfeel and aroma, but most people can't tell the difference.

2. When brewing a blonde ale, a hot mash leads to a higher final gravity and better mouthfeel and aroma, but most people can't tell the difference.

3. When brewing the Centennial Blonde Ale from the HomeBrew Talk website's top 10 list, a hot mash leads to a higher final gravity and better mouthfeel and aroma, but most people can't tell the difference.

4. When brewing the Centennial Blonde Ale from the HomeBrew Talk website's top 10 list using Marshall Schott's brewing system and processes, a hot mash leads to a higher final gravity and better mouthfeel and aroma, but most people can't tell the difference.

5. When brewing the Centennial Blonde Ale from the HomeBrew Talk website's top 10 list using Marshall Schott's brewing system and processes, a hot mash leads to a higher final gravity and better mouthfeel and aroma according to the particular people surveyed by Marshall Schott in the original experiment, but those people still generally can't tell the difference.

I think it's a legitimately hard question where the reasonable conclusion lies (assuming you believe the results have decent internal validity—an open question, as noted above). I wouldn't go all the way to 5, but I wouldn't be at 1 either.

The right way to deal with evidence like this, I think, is to treat it as a thought-provoking example and a chance to question received wisdom about brewing. It's not as though Brülosophy is coming into a space where a lot of high-quality quantitative work has been done already (or at least, work that is publicly available—I assume the big beer companies have done some pretty high-quality research—I believe the "student's T" was even invented at Guinness). The results raise questions, though they certainly don't answer them conclusively. Just by way of example, Marshall's fermentation temperature experiments (here, here, and here) are certainly eye-opening for someone who, like me, believes that fermentation temperature control is a key aspect of good brewing. I'm not going to take the attitude that temperature doesn't matter, but I am going to be a little more circumspect in telling new brewers that it's one of the most important variables to control.

 

Fermentation temperature can be very important depending on the strain. For example, WY1388 has a published temperature range of 64-80F. I double dog dare you to make a 9% Golden Strong ale with 1388 above 76F in the beginning of fermentation. You will be drinking nail polish remover and it wouldn't surprise me if Brulosopher's tasters couldn't tell the difference.

 

How would you advise new brewers as regards to fermentation temperature? Would you suggest that they ferment in the recommended temperature range or would you state that it doesn't matter?

Cheers!

 

@scurvy311 , with those aspirations, I think the best thing you can do is find a local brewery to volunteer at. Volunteering may be cleaning kegs or graining out, etc.. but it will afford you to be included in practical brewing conversations with the brewery staff there.

I agree with @telejunkie . Formal brewing education is mostly theory and to a much lesser extent practicality. You'll often hear of graduates with no prior brewing experience that have a hard time even connecting hoses with tri-clamps.

If you do not seek to enter the industry as a full time brewing staff, I would recommend volunteering and reading into more serious brewing texts, such as those by Dr. Bamforth or Michael Lewis. The brewing elements series is a good one too. The book on yeast and the book on water are very detailed.

Honestly though, the biggest help you can be to friends starting a brewery is if you have any engineering, electrical, mechanical, plumbing proficiencies. Starting up a brewery is mostly nuts, bolts, power tools, construction and to a much lesser extent brewing theory.

 

Certainly assembling the brewery needs the skills you listed.

Selecting the equipment configuration requires brewing process knowledge. What skill set is the ‘architect’ of the brewhouse? I know a lot of skilled engineers (electrical engineers, mechanical engineers, etc.) but they would be unable to ‘design’ a brewhouse.

Cheers!

 

"Much lesser extent brewing theory"

 

I referred to it as "crappy" because it comes across as a rant from someone who doesn't appreciate/like how empirical economics has changed in the last 20-30 years. Without going too deep in the weeds, Deaton is arguing that a RCT often doesn't have external validity because of all the examples in the quote. But, his idea of external validity is based on theoretical assumptions (general equilibrium) that are in some cases completely indefensible from a real world point of view. With that said, Deaton is much smarter than I am (so is Heckman) I just disagree with their perspective as far as the true value of economic theory to modern empirical economics.

To bring it back to beer, there is nothing wrong with a RCT in brewing because we can do experiments to isolate individual affects (mash temp, fermentation temp, yeast, trub,...). The problem with the Brülosophy experiments is not that he is doing a RCT, it is that his sample sizes are way to small to ever hope to be able to identify a meaningful difference. From an experimental science point of view, a RCT can be both internally and externally valid. In economics, a RCT can give a very clear experimental effect (internally valid) but not tell us anything about the real world (externally valid). You see the same problem with a lot of psychology experiments. Internally valid, but because they mostly use college age kids, they are not externally valid.

Good post on your part in responding to my less than sober "crappy" comment, cheers

 

I would still urge a beginning homebrewer to pay attention to fermentation temperature, and I would even emphasize it as one of the most important control points. But I'm not nearly as confident in my opinion as I was before I read that post. Part of my point is that it's hard to give advice unless you have a pretty solid understanding of cause and effect, and those experiments have caused me to be a bit more humble about what I "know" about homebrewing. I may start a new thread about this issue, because I think it's pretty important for users of this forum.

Right, I don't think the experiments can be regarded as conclusive at all. On the other hand, it's not totally useless data. The experiments are better-designed than anything I've done with my homebrewing. And when the results are surprising, it's a good opportunity to re-think what we know about brewing.

 

Some of what I read in these experiments sets off alarm bells. For example, in the mash temperature experiment, the higher mash temp resulted in a beer with an FG 9 points higher than the lower mash temperature. Of 9 tasters (the supposedly better tasters BTW, the ones who had passed the triangle test), only 4 were able to guess which one was mashed higher after the nature of the comparison was revealed. Are we supposed to believe that a 9 point difference in FG is basically undetectable? Personally, there's not enough there for me to even start to re-think what I think I know about residual sugars. But if someone wants to repeat the experiment, I'd guess I's be happy to be a taster.