Music soothes the savage Lactobacillus helveticus

I'm sure you saw the news item. The one about how exposing cheese to different types of music during its formative years can give cheese distinctive flavors? It was determined that hip hop music is best, that is, if you like a cheese with a fruity flavor.

It's a compelling thought. On the one hand, it's silly and ridiculous since bacteria don't have ears (like corn does). And even if the bacteria did have ears, does a wheel of cheese have enough sentience to distinguish between The Magic Flute and Stairway to Heaven? I mean, if I have a good hangover going on, I would be hard pressed to tell the difference!

On the other hand, sound is energy. Pick the right range of frequencies, and it can be translated into heat, which (I assume) could change the flavor of the cheese. Sound is also mechanical energy. If you hit the right frequencies, you presumably could set up standing waves that encourage some sort of structure to the cheese. Or maybe there are polymers in cheese that are long enough to have resonant frequencies in the audible range?

I dunno. Maybe cheese is just smarter than we give it credit for. After all, just look at how intelligent Wisconsinites look with cheesehead hats! (Due to the family friendly nature of this blog, I have decided not to include pictures of fans wearing the classy cheesehead bra. Google it if you are interested. It really is a thing.)

The general idea of the experiment

The cheese maker Käsehaus K3 in Burgdorf, Switzerland placed nine wheels of Emmental cheese in nine separate crates for aging. The wheels were exposed to various sounds over the next six and a half months. One wheel got 24/7 of Led Zeppelin. Another got Mozart. Still others got hip-hop, ambient, and techno. Three cheeses had to suffer with a rather constant tone. Finally, one cheese got peace and quiet. This was called the control group.

After six months in these boxes, judges did a random blind assessment of the cheeses to assess whatever it is that official cheese assessors assess. From the images below, it would appear that olfaction is 80% of it. The assessments were repeated, and the results were consistent. Here is a quote from the Reuters article: "Beat Wampfler, the cheesemaker behind the project, said the cheeses were tested twice by the jury and both times the results were more or less the same."

Photos of the judging from the Käsehaus K3 website

What the media has to say

Many news outlets have covered this groundbreaking experiment. Here is a sampling of the reports of the findings.

From NPR: "[The  professional food technologists] concluded the cheese wheels exposed to music had a milder flavor compared with the control cheese. The group also determined the cheese that was played hip-hop had "a discernibly stronger smell and stronger, fruitier taste than the other test samples"

From Smithsonian: "The experts said A Tribe Called Quest’s [hip-hop] cheese was “remarkably fruity, both in smell and taste, and significantly different from the other samples.”

The best music to age cheese by

From Reuters: "“The differences were very clear, in term of texture, taste, the appearance, there was really something very different.”"

Well. That certainly sounds conclusive.

Digging a bit deeper

Before I continue, let me say this. I love this work. It's offbeat (no pun intended) and innovative. It opens the way for a better understanding of how things work. It rests in the cracks between science and craft.

On the other hand, I hate to be a spoilsport, but I am skeptical. Hip-hop?!?!?! Really?  I'm not so much a fan of hip-hop, and I like cheese. A good cheese should have the same taste in music as I do. This all creates cognitive dissonance in my little brain.

So, I swam upstream to read a more first-hand-ish version of the results. Here is the original press release, and here is a website version of the experiment.

They did some good things, by which I mean, they used some Science. Here is one thing: "The milk was produced by the same farmer and was processed in the same kettle on the same day of production."

I have already mentioned another thing that they did right. They repeated the assessments and concluded that they were in agreement, that is, the differences weren't just because of the variability in the humans smelling the cheeses. I couldn't find the actual assessment data, but I will assume that they applied the right stats on the assessments to verify that the judges agreed. (That might not be a good assumption, of course. Statistics is a slippery subject.)

But...

All that said, here is a quote from the original press release.

In general, it can be confirmed that the discernible sensory differences detected during the
screening process were minimal. The conclusion that these differences did indeed confirm the
hypothesis, namely that they can clearly be traced back to the influence of music, is conceivable,
but not compelling.

This is common statistics-speak. I will translate for the non-statistician. They started with the hypothesis that music can affect the maturation of cheese and set out to either prove or disprove it.

My professor for Stats 101 +/- 2.7

One possible outcome would be that the judges all said the cheeses smelled and tasted the same. The conclusion would be that, at least for this particular combination of cheese type, music selection, and means for delivering the music, the music has no effect on the cheeses.

Another possible outcome would be that the judges may have agreed that there is a difference between at least some of the cheeses. Upon hearing this, the conclusion from a typical layperson might be "Aha! Music causes cheese to age differently!!" The comments in the articles from NPR, Smithsonian, and Reuters all promote this conclusion. It makes for good headlines.

But a statistician is more careful with the analysis of the results. The faithful statistician is open minded to other possible interpretations of the data. A statistician concludes that the experiment does not disprove the hypothesis that music influences cheese flavor. While English majors abhor this double negative construct, but it is key to critical thinking to see the difference between "does not disprove" and "proves".

The statistician recognizes that "music affects the aging cheese" is one possible explanation for the outcome, but there could be other explanations. Here are some alternate explanations, some more plausible than others.

1) There are several pictures where the wheel of cheese has a placard that identifies the type of music that it listened to. Did the judges see the placard? (This is unlikely. The website says that they followed ISO 13299, which precludes any presentation of the samples that might identify individual cheeses.)

2) I noticed from the pictures that all the judges appear to be together in the same room. Is there a possibility that one judge picked up non-verbal cues from another judge?

3) Quoting from the original press release: "the discernible sensory differences ... were minimal". Hmmm... Maybe the differences were due to subtle differences in the way each cheese was processed? One of the cheeses was probably poured into a mold first, and another was poured last. Some of the cheeses were aged closer to the ceiling, and some closer to the floor -- there is likely a small difference in temperature. Some were closer to the door, which might open the door to more airborne bacteria. Perhaps one cheese received a little more personal attention (and/or bacteria) when workers did their routine inspection?

I don't claim to understand the potential causes of variability in the manufacture of cheese, and I am certainly not casting aspersions on the folks at Käsehaus K3. I just know that there are causes of variability in all manufacturing, however small or large.

4) Were the results analyzed for statistical significance? I say this because people are not good with statistics. Without rigorous statistics, we almost invariably jump to conclusions. Statistics is a tool that forces us to make sure those conclusions are valid. I did not see any detailed description of the statistics that the researchers applied to the assessments, so either the analysis of consensus was minimal or they recognized that the audience would be bored with it, since people are not good with statistics.

5) Were the results analyzed for statistical significance? I say this because the website lists only eight judges. Don't get me wrong. I commend them for putting this level of effort into the experiment. But, consider the fact that a rigorous poll or pharmaceutical test will survey thousands of people in order to provide statistically valid conclusions. But, don't get me wrong. I'm not saying "those darn cheesemakers really should have hired a thousand cheese testers." I am saying that we need to review the data in light of the statistical significance due to the limited number of judges.

6) Were the results analyzed for statistical significance? I say this because they have included a control cheese which didn't listen to any music. If you are testing whether music affects the flavor of cheese, the "obvious" statistical test would be to determine the variation of the eight cheeses that listened to music, and then test for whether the control cheese is within this variation.

Who understands this tripe, anyway!?!?!?

But, quoting from the website: "Thus, the reference sample was comparatively most pronounced in odor, as well as in taste, whereby here also the sample sinus 2 (medium frequency) was perceived as intensively." The control for this experiment was within the natural variation of the rest of the cheeses, so the hypothesis "sound has an effect on cheese" seems to be not supported by this experiment.

My favorite alternate explanation

There is normal variation in all manufacturing processes. The experimenters were careful to make sure that the milk came from the same farm and that the milk was all processed the same way. I am sure that K3 has a standardized practice for making cheese. Good on them. But even in the tightest of manufacturing facilities, there is variation.

That means that some of the cheeses will naturally taste spicier than others, while some will be fruitier -- even if the music was completely feckless. One of the cheeses will be the fruitiest. It could have been the cheese that listened to ambient music, or it could have been the Mozarted cheese. If by random chance the cheese that listened to techno music was the fruitiest, then the articles would all be talking about the effect of techno, rather than the effect of hip-hop.

My favorite alternate explanation is that through normal and random variation, one cheese will be chosen as the fruitiest, regardless of whether there is any effect of music on cheese aging.

Followup

Every good research paper ends with a statement like "clearly further research is required to keep the researchers employed". I say that with tongue-in-cheek, but refinement and replication are at the very core of Science.

I was heartened to read this from the original press release: "More extensive testing is required in order to determine whether there is a link between exposing cheese wheels to music as they mature and discernible sensory differences."

The press release goes on to say that tighter controls and more sampling are required. From my previous comments, you could gather that I agree. I would add that rigorous statistics is always a good thing.

I would suggest another experiment: put all the mp3 players on pause, and repeat the 9 cheese experiment. Use this data to better understand the natural process variation.