Ruminations on beer

The word "beer" has occurred in 14 of my blog posts so far. Go figger. As all my friends know, I don't even like beer. And I always tell the truth in my blog posts.

Beer is frequently featured in my posts because of Beer's law. I am probably the first person in history to remark on the connection between August Beer's name and the yellow, foamy liquid. And I am certainly the first person to use actual beer to demonstrate Beer's law.

Beertones

Beer's law is a law about light and color measurement. So, you can imagine my delight when the world finally got serious about measuring the color of beer! The Beertone guide below puts an end to all those arguments in the tavern about whose beer is darker, and allows you to order beer buy RGB value. A simple flip of the deck under properly calibrated lighting can identify the color of each and every beer in the Beertone database.

The Beertone Guide

The legacy of Hugh Beaver

Speaking of bar arguments, Sir Hugh Beaver was a guy very interested in eliminating them. He was on a hunting trip and found himself amidst an argument about whether the golden plover or the grouse was the fastest European bird [1]. He found it devilishly hard to research the question, so he decided to create a book to answer all such questions. What does this have to do with beer? Sir Hugh Beaver was then the director of the Guinness Brewery [2]. Originally, it was just a marketing gimmick. He soon realized that this was a bonafide business in its own right.  

Hugh Beaver of Guinness and Hugh Beaumont of Leave It to Beaver
Two lives inextricably intertwined

Speaking of publications from Guinness, the book of world records was not the first time that the Guinness Brewery became famous for its publications. The so-called "Student's t-test" came out of that little place in 1908 [3]. William Sealy Gosset was researching ways to improve all matters having to do with barley and yeast, and beer production. At the time, he thought his work was of little consequence. Little did he know that his name was to go down in the history of statistics. 

Well, his name didn't quite go down in history, but his pseudonym did. It seems that a previous Guinness employee had spoiled the water. Trade secrets had been published, so Guinness adopted a policy that employees were not allowed to publish anything. Gosset negotiated an agreement with Guinness where they allowed him to publish so long as he published under a pseudonym and did not publish any of their data. The stated author of this landmark paper in statistics (March 1908 volume of Biometrika) was "Student" - hence the famous Student's t test that everyone in Stats 201 promptly forgot after the finale exam. 

The amazing world of Guinness bubbles

Speaking of bar arguments and Guinness, to this day, there has been an ongoing argument about the direction of the flow of bubbles in a freshly poured pint. It appears that bubbles travel downward, rather than upward as one might expect. One enterprising group of scientists at Stanford University headed down to the pub with a high speed camera to test this. Optical illusion, or fact? Their conclusion was that the "...bubbles at the center rise up and create a circulation in the glass.  The circulation causes bubbles at the edge of the glass to be pushed downwards."

OMG! The bubbles really do head for the bottom of the glass!

This is not the last word, by any means. The critical research continues. Last year saw the publishing of a paper at Cornell which literally turned the world of fizzy-ology upside down:

"In this paper, we use simulations and experiments to demonstrate that the flow in a glass of stout beer depends on the shape of the glass. If it narrows downwards (as the traditional stout glass, the pint, does), the flow is directed downwards near the wall and upwards in the interior and sinking bubbles will be observed. If the container widens downwards, the flow is opposite to that described above and only rising bubbles will be seen."

Pint and Anti-pint

Just as an aside, I tried this experiment at home. I could not replicate their results. Every time I turned the pint glass upside-down, all the bubbles headed downward. Along with the stout.

But the two previous explanations lack the big words to give them the level of pretension that the whole topic deserves. This following paper provides adequate levels of pretension. The lead author is from Limerick, Ireland, so she no doubt is an expert on stout. (Guiness is headquartered in Limerick.) Here is what she has to say:

"Our theory involves a physically based regularization of the basic equations of the two-phase flow, using interphasic pressure difference and virtual mass terms, together with bulk or eddy viscosity terms."

I offer the following as an alternative for the abstract: [4] 

There were some researchers from Limerick

Who proved bubbles go down - quite a mean trick.

They modeled two-phase flow 

To explain why it's so

With a pressure difference interphasic.

I am guessing that my own name may not go down in history as the author of the first limer-abstract. It's a shame. But I realize that this limerick won't get much airplay because limericks are supposed to be naughty. [5]

To beer or not to beer?

Speaking of "naughty", what about beer and human mating rituals? 

I have been reading a delightful blog by Christian Rudder. He has the enviable position of being allowed free access to the scads of data from the dating site "OkCupid". They have a database with zillions of questions, answered by zillions of people, and he has been doing correlations to find answers to which of these questions correlate with each other. For example, one would expect that if someone identified themselves as being into Harleys and Metallica, it's likely that they would also be into My Little Pony. His data can answer that. 

But Christian wasn't really looking for My Little Pony fans, he was looking for something more practical. I am guessing that he knew something that I discovered the hard way--the Heisenberg Uncertainty Principle of First Dates: The mere act of asking a woman if she might be willing to smooch on a first date will effect whether she will. Generally speaking, I found that the effect is negative.

So, Christian wanted to know what "safe" question you could ask on a first date to get some indication as to whether you might get lucky. He had the answers to the question "would you consider sleeping with someone on the first date". And he had answers to a zillion other questions. Here is the astounding revelation in his blog post about safe questions for a first date. "Among all our casual topics, whether someone likes the taste of beer is the single best predictor of if he or she has sex on the first date."

Ask her if she likes beer!

Speaking of dating and beer, let's talk about beer goggles. Do "the girls all git purdier at closin' time", as the song says? Amanda Ellison, senior lecturer in the Department of Psychology at Durham University and author of the book "Getting your head around the brain" would like to dispel the rumor of beer goggles. Here is what she has to say about the effect of alcohol:

The area of the brain that makes us want to mate keeps functioning, no matter how much we drink, meaning that people can still assess how visually-appealing others are. ...alcohol switches off the rational and decision making areas of the brain while leaving the areas to do with sexual desire relatively intact, and so this explains beer goggles. 

Before and after that third pint of Guinness

We don't rate people as getting more attractive when we have a few under the belt. We just get better at making bad decisions. And mind you... those decisions often find us getting into trouble with the law. Beer's law.

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[1] Apparently the question about whether the African or the European swallow was faster is uncontested, since the bridge keeper at the Bridge of Death is the sole decider of Truth.

[2] This epiphanic moment that marked the nascence of the Guinness Book of World Records was on my birthday, November 10. Beaver was born in Johannesburg in 1890. I visited Johannesburg 120 years later. I once had a copy of the Guinness Book, and I once had a Guinness beer. To the best of my knowledge, neither Hugh nor myself have ever robbed a bank. The coincidences are endless.

[3] Student's t test is not (as you would expect) an annual competition sponsored by some school between Lipton, and Bigelow, and Celestial Seasons. It is a method in statistics that is used to test the validity of experimental results. Suppose I want to find out if having a couple of beers for breakfast will improve the appearance of my hair. I run a number of trials, on some days I have my normal breakfast of two beers, and on other days I abstain. For each day, I count the number of compliments I get on my hair. At the end of the experiment, if I get more compliments on beer days, it might be because the beer really does make my hair look better, or it could just be random. For example, maybe on beer days, I just happened to get served more often by that cute young gal at Starbucks who has a crush on me. Student's t test is a way of gauging the likelihood that the experimental results might just be random chance.

[4] I am following my normal practice of poking fun at things that are too difficult for me to understand. Its a defense mechanism.

[5] (From the Wikipedia entry on limericks) Gershon Legman, who compiled the largest and most scholarly anthology, held that the true limerick as a folk form is always obscene, and cites similar opinions by Arnold Bennett and George Bernard Shaw,[5] describing the clean limerick as a "periodic fad and object of magazine contests, rarely rising above mediocrity." From a folkloric point of view, the form is essentially transgressive; violation of taboo is part of its function.

One Beer's law too many

Some people may think that Beer’s law has to do with underage drinking, and that August Beer is what comes before OktoberFest. Beer’s law is, however, one of the coolest laws of photometry, and August Beer is the guy who it is named after. (For a complete discussion of how it got that name, skip to the end of this blog post.

This blog post is a re-enactment of a seminal experiment that a preeminent researcher reported on back in 1995. This phenomenal scientist has had such a profound influence on the worlds of printing and colorimetry, that I am tirelessly committed to the promulgation of his work. I am speaking, of course, about myself.

Experimental setup

The picture below details the equipment to be used in this experiment. At left is a constant current power supply, which provides power for the blue Luxeon LED. This LED shines into the optical assembly, which is supported by one of the biggest books I have on color science. At the far right is the sensor for an expensive light sensor, with the control unit show on the expensive black carpet. The observant reader will no doubt be impressed by the huge expense that I must have gone through to dig this pile of junk out of my basement.

Expensive equipment used for this experiment

The lights were turned down and the system calibrated so that the light meter read 100.0 banana units when there was nothing between the light source and the detector, as shown below.

Expensive optical stuff, bored, with nothing to read

Now the party begins. I cracked open a cold one and set it in the beam. Note that the reading has dropped to 90.0 banana units, indicating that 10.0 banana units of light got caught by the amber fluid and never quite made it home. I can definitely identify with these photons.

Same set up, but with one sample cell

As they say, you can’t milk a camel while standing on one leg, so let’s order another one. But before it gets set down on the bar, let’s take a guess at what the light meter will read. Hmmm…. The first sample dropped it by 10.0, so it would make sense that the second one would so the same. My guess at the results: 80.0.

Same set up, only this time with two samples

For those of you who agreed with my guess, it was commendable, but wrong. There was indeed a pattern established, but not the one you were thinking of. Why did it go down to 81.0, instead of 80.0? For every 100 photons that entered the first sample, 10 of them were absorbed, and 90 were transmitted on to the second sample. Upon reaching the second sample, the same probabilities apply. Of the 90 photons that made it to the second sample, 90% of those made it out, so that there were 81.

You now know Beer’s law.

But just to make sure the concepts are all down, let’s take this one step further. How about three samples? 90% X 90% X 90% = 72.9%, as verified by the highly sensitive experimental set up below.

Results for three samples

One last thing… Can you guess what kind of beer was used?

Miller Lite – the official beer of color scientists everywhere

Disclaimers – Do not try this experiment at home. I am a trained professional. The mixing of beer and scientific equipment is not recommended. No beer was wasted in the photoshoot for this blog. I cannot say the same for the scientist who performed the experiment.

Who invented Beer’s law, anyway?

Some folks may have just assumed that Beer’s law was named after William Gosset, who was a pioneer in statistics, and worked for Guinness. That would be a good guess, since he was a smart guy. It would have been just like him to have a really cool law of physics named after him, since he invented the t test, which was named after Student, which was actually his pen name. But that’s another interesting story.

The guess is unfortunately wrong, since Beer’s law was named after August Beer. This is yet another in my series of mathematical misnomers.

This law of physics was first discovered by the father of photometry Pierre Bouguer in 1729. August beer didn’t discover this law until over a century later in 1852. Beer worked with  Johann Heinrich Lambert on a book (“Introduction to the Higher Optical”) that was published in 1860. So naturally, the law has become known as “Beer’s law”, “Beer-Lambert law”, “Beer Lambert-Bouguer law”, “Lambert-Bouger law”, “Lambert’s law”, and “Bob”.

Why is it known in the printing industry as “Beer’s law”? There are two key influences that led to this egregious misnomer. The first was a landmark 1967 book by J.A.C. Yule, “Principles of Color Reproduction”. Any book with the word “reproduction” in the title is apt to move quickly. I just checked with Amazon. They only have two copies left.

The second thing that probably had an even greater effect was the frequent use of the eponym by the eminent applied mathematician, color scientist, mathematics historian, and all around nice looking guy, John “the Math Guy” Seymour. He has made no bones about why he decide on this name among all the potential candidates. I quote here from his paper delivered at the 2007 Technical Association of the Graphic Arts:

Since there seems to be little agreement about who is responsible for which law, I have chosen to refer to the statement that optical densities of filters add as Beer’s law. My decision is not based on historical evidence, but on the gedanken I introduced in a paper given at IS&T (Seymour, 1995). In this, I demonstrated the law by using a varying number of mugs filled with beer. My hope is that my further corruption of already corrupt historical fact will help remember the law!

Brilliant words by a brilliant man, indeed.