Cheers!

Humans have been making and consuming alcoholic drinks for a very long time.

We're hardly the only animal species to experience the psychotropic effects.  You may recall that about ten years ago a story from Sweden (Höme of the Majestic Mööse!  Extra points if you know the reference) in which one of the antlered behemoths got drunk eating fermented fallen apples, tried to climb the apple tree, and got stuck.  Not all species experience the same effects, though.  A 2008 study of pen-tailed tree shrews in Malaysia found that they habitually consume naturally-fermented nectar that raises their blood alcohol levels to well above the legal limit for humans, and show no ill effects whatsoever.  Presumably if they've evolved with that kind of diet, they've developed a mechanism for detoxifying the alcohol, or at least avoiding the psychological effects.  The jungles of Malaysia are thick with predators, and for a small furry mammal to spend all its time stumbling around dead drunk would be a good way to end up actually dead.

The earliest hard evidence of humans making wine or beer comes from near Jiahu, in the Yellow River Valley of China.  Pottery dating from about 6800 B.C.E. was found that had residues of fermented rice, honey, grapes, and hawthorn berries; around the same time, there's evidence of grape wine and barley beer being made in the Middle East.  I've often wondered what that stuff tasted like, as compared to our refined and filtered wines, beers, and spirits a lot of us enjoy today.  Back then, they were relying on wild yeasts and bacteria to do the fermenting, and that undoubtedly led to highly variable results (and a lot of spoilage).

The written records of the Greeks and Romans certainly mention wine and beer, and (especially with the Romans) we know a good bit about their winemaking techniques.  Grape juice, sometimes flavored with spices, honey, or other fruit juices, was boiled, then filtered, poured into clay amphorae, the lids sealed with beeswax, and then buried for a period that could vary from weeks to years.  The resulting liquid was then decanted and bottled.  This was when it was discovered that the soil type, climate, and grape variety had huge effects on the outcome; Roman wines ran the spectrum from surrentine (which the Emperor Tiberius sneeringly called "generous vinegar") to falernian (so expensive it was only available to the very rich but potent -- it was not only delicious, but was aged for up to twenty-five years and had an alcohol content of around fifteen percent).

[Image is in the Public Domain]

We just learned a little more about the production of vino from an archaeological find from the harbor of San Felice Circeo, ninety kilometers south of Rome.  Wine jars were unearthed in a seabed deposit that still had residues of the wines they contained.  Both red and white wines were found, along with pollen identifiable as coming from several varieties of wild grapes that grow in the area.  (Whether the vines themselves were cultivated is unknown; but those varieties are still found growing wild nearby.)  Interestingly, the amphorae were sealed not with beeswax but with pine tar, and apparently the pine tar was used not only as a sealant but to flavor the wine itself.  Maybe the result was something like Greek retsina, which people seem either to love or hate (I like the flavor, but my wife's opinion is if she wanted to chew on a pine branch, she'd go do it).

It'd be interesting if we went back to Roman times and attended a feast, where it would fall on the spectrum between delectable and revolting.  I wrote last October about a fellow named Andrew Coletti who has tried to recreate bunches of historical recipes as accurately as possible, and found that one of the Roman dishes bore an uncanny resemblance to french fries with ketchup.  But I have no doubt that some of the food and drink would taste pretty strange to us.  I'd still want to try it, though.  I don't hesitate to try local foods when I travel, and have rarely had a bad experience, although I did draw the line at the Icelandic "delicacy" hákarl, which is fermented shark meat.  It apparently has a "strong ammonia smell," and the late Anthony Bourdain said it was "the single worst, most disgusting, and terrible-tasting thing" he'd ever consumed.  Chef Ainsley Harriott was even more descriptive, describing eating it as being like "chewing on a urine-soaked mattress."

I've heard of "acquired tastes," but that's over the line.  In fact, for me, that's so far over the line that from there I wouldn't be able to see the line using a powerful telescope.

But Roman wine?  Sure, I'd give it a go, even the "generous vinegar" one.  Who knows, maybe I'd love it.  Chacun à son goût, and all that sort of thing.  But think about this if you go out for a pint or a glass of wine with friends tonight -- you're partaking in a tradition that goes back in some form or another for thousands of years.  Pretty cool, when you think about it.

Cheers!

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My goodness...

In this week's installment of Research I Can Get Behind, we have: some scientists who have figured out why bubble cascades happen in a pint of Guinness.

Being a big fan of the classic Irish dark brew, I've wondered the same thing myself.  When a pint is poured, a good bartender will make sure the patron doesn't drink the beer until it's settled for a minute or two.  This has afforded me the opportunity to observe a very strange thing; the bubbles in Guinness seem to sink rather than float.  I'd always figured that this was an optical illusion of some kind, since the beer definitely clarifies from the bottom upward (and the foam forms at the top), but it's a pretty persistent illusion, so that's where I left it.

Probably also because immediately after considering the question, I have a pint of beer to drink and thus more pressing matters to occupy me.

But according to Tomoaki Watamura, Fumiya Iwatsubo, and Kazuyasu Sugiyama of Osaka University, and Kenichiro Yamamoto, Yuko Yotsumoto, and Takashi Shiono of the Research Laboratory for Beverage Technology (of Yokohama), the bubbles really are sinking.  The authors write:

Following Archimedes’ principle, bubbles in liquid generally rise because of the gas-liquid density difference.  Despite the natural rising behaviour of bubbles, after pouring Guinness beer in a pint glass, the bubbles can be observed to descend.  At the same moment, a vast number of small bubbles with a mean diameter of 50 μm (only 1/10 the size of those in Budweiser or champagne) disperse throughout the entire glass.

The downward motion was explained through convection and drag:

Curiously, although creamy bubbles have been served in Guinness beer for more than half a century, the mystery of such a cascading motion of bubbles has been debated in terms of fluid dynamics ever since.  Because the black colour of Guinness obstructs the physical observation in a glass, computational simulations have been a valuable tool to understand the bubble distribution and motion.  The computational investigation has concluded that when Guinness is poured into a typical pint glass, which widens towards its top, the rising motion of bubbles creates a clear-fluid (bubble-free) film above the inclined wall.  The dense clear-fluid film falls, whereas the bubble-rich bulk rises, which is known as the Boycott effect.  Accordingly, we can observe the descending bubbles entrained into the downward flow in Guinness, which is seemingly paradoxical in light of Archimedes’ principle.

Then they got interested in how the "texture" of the beer appeared to move downward in waves, which couldn't be explained by the bubbles simply being dragged along by downward fluid flow.  They attribute it to roll-wave instability -- the same principle that creates the pulses of rainwater sheeting down a window during a rainstorm.  I have to say that at this point I got lost in the technical details -- despite my bachelor's degree in physics, my comprehension of the mathematics of fluid flow is virtually nil -- so if you want more information, you'll just have to check the paper out for yourself.

Who knew that beer could be that complicated?

But one other thing came out of the study that I found fascinating, and that is that they discovered the optimal tilt angle for pouring a pint -- fifteen degrees from vertical, including the curvature of the glass.  Which probably explains why I have a difficult time pouring a pint without it ending up 90% foam and 10% beer, and having to sit around waiting for twenty minutes while the whole thing simmers down before I can drink it.

So that's our scientific research for today.  Consider that the next time you think that scientists don't know how to have fun.  It's kind of cool to know why the sinking-bubble thing happens, although I'm sure my comprehension of the Watamura et al. paper was rudimentary at best.  Or maybe I should just do my own empirical research.  Nothing like hands-on experimentation.

If you see me tonight at the pub, that's what's going on.

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I grew up going once a summer with my dad to southern New Mexico and southern Arizona, with the goal of... finding rocks.  It's an odd hobby for a kid to have, but I'd been fascinated by rocks and minerals since I was very young, and it was helped along by the fact that my dad did beautiful lapidary work.  So while he was poking around looking for turquoise and agates and gem-quality jade, I was using my little rock hammer to hack out chunks of sandstone and feldspar and quartzite and wondering how, why, and when they'd gotten there.

Turns out that part of the country has some seriously complicated geology, and I didn't really appreciate just how complicated until I read John McPhee's four-part series called Annals of the Former World.  Composed of Basin and Range, In Suspect Terrain, Rising from the Plains, and Assembling California, it describes a cross-country trip McPhee took on Interstate 80, accompanied along the way with various geologists, with whom he stops at every roadcut and outcrop along the way.  As usual with McPhee's books they concentrate on the personalities of the people he's with as much as the science.  But you'll come away with a good appreciation for Deep Time -- and how drastically our continent has changed during the past billion years.

[Note:  If you order this book using the image/link below, part of the proceeds will go to support Skeptophilia!]

Trouble brewing

A general rule of historical anthropology is that societies only last so long, and inevitably go into decline and are superseded.

The causes, though, are numerous and often mysterious, which is why your typical one-line explanations -- like "classical Rome collapsed because of the invasion by barbarian tribes" -- are inaccurate oversimplifications at best.  Sure, the barbarians didn't help matters, but centuries of misrule, overreach by emperors greedy for land (leading to revolt in outlying provinces they no longer had the military strength to control), unfavorable alterations in climate, and repeated outbreaks of the plague were all major contributors to the downfall of the Pax Romana.

Some civilizations have collapsed more suddenly, and for a few of them, we have no real idea why.  Mycenaean Greece, the "Golden Age of Heroes," went into decline around 1200 B.C.E., and by 1100 was erased entirely, their cities and palaces abandoned.  From a hastily-scrawled clay tablet found at the Palace of Pylos, one of the main Mycenaean strongholds, we get the impression that invasion (in this case by the Dorians, a tribe from northern Greece) may have been a contributor:

The enemy grabbed all the priests from everywhere and without reason murdered them secretly by simple drowning.  I am calling out to my descendants (for the sake of) history. I am told that the northern strangers continued their (terrible) attack, terrorizing and plundering (until) a short time ago.

[It may interest other linguistics geeks that the above passage was translated by Michael Ventris, who along with Alice Kober finally deciphered Linear B -- a script which beforehand was entirely mysterious, even as to what language it represented and which characters stood for which sounds.  In fact, it wasn't even known whether the characters stood for single sounds, syllables, or entire words.  Imagine facing that as a task...]

Anyhow, it's unlikely that the Dorian invasion is the sole reason Mycenae fell.  After all, these are the people who kicked some major ass during the Trojan War; a bunch of invading barbarians wouldn't have successfully eradicated the Mycenaean civilization unless there had been other factors at work as well.

My point is, what destroys civilizations, not to mention what keeps them alive, is seldom a single factor.  But some anthropologists working in South America have identified one that seems to be critical to a society's survival:

Beer.

I'm not making this up.  Patrick Ryan Williams (Field Museum), Donna Nash (Field Museum and University of North Carolina Greensboro), Josh Henkin (Field Museum and University of Illinois at Chicago) and Ruth Ann Armitage (Eastern Michigan University) are the authors of a paper in Sustainability that was released last week, looking at the role of breweries in the Wari society, which flourished in what is now the western half of Peru for over five hundred years.  The authors write:

Utilizing archaeometric methods, we evaluate the nature of production of feasting events in the ancient Wari state (600–1000 CE).  Specifically, we focus on the fabrication of ceramic serving and brewing wares for the alcoholic beverage chicha de molle.   We examine the source materials used in the creation of these vessels with elemental analysis techniques. We then assess the chemical traces of the residues present in the ceramic pores of the vessels to detect compounds indicative of the plants used in chicha production. While previous research has identified circumstantial evidence for the use of Schinus molle in the production process, this research presents direct evidence of its existence in the pores of the ceramic vessels.  We also assess what this material evidence suggests about the sustainability of the feasting events as a mode of political interaction in the Wari sphere.  Our evaluation indicates that regional resource use in the production of the ceramic vessels promoted locally sustainable raw material procurement for the making of the festivities.  Likewise, drought resistant crops became the key ingredients in the beverages produced and provided a resilient harvest for chicha production that was adopted by successor groups.

"This study helps us understand how beer fed the creation of complex political organizations," said study lead author Patrick Ryan Williams in an interview in Science Daily. "We were able to apply new technologies to capture information about how ancient beer was produced and what it meant to societies in the past...  It was like a microbrewery in some respects. It was a production house, but the brewhouses and taverns would have been right next door...  People would have come into this site, in these festive moments, in order to recreate and reaffirm their affiliation with these Wari lords and maybe bring tribute and pledge loyalty to the Wari state...  We think these institutions of brewing and then serving the beer really formed a unity among these populations, it kept people together."

[Image courtesy of the Creative Commons http://www.pdphoto.org/PictureDetail.php?mat=&pg=8748]

Which makes total sense to me.  I don't know about you, but getting together with friends for a nice pint is often the high point of my weekend.  And yeah, we could get together and have soda and Shirley Temples, but... it just wouldn't be the same, somehow.

So next time you have a beer, keep in mind that you're not just drinking a fizzy, mildly alcoholic beverage, you're actually helping society to cohere.  Which, I think, is a noble thing we're all doing.

Bottoms up!

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This week's Skeptophilia book recommendation is a classic, and is pure fun: Man Meets Dog by the eminent Austrian zoologist and ethologist Konrad Lorenz.  In it, he looks at every facet of the human/canine relationship, and -- if you're like me -- you'll more than once burst out laughing and say, "Yeah, my dog does that all the time!"

It must be said that (as the book was originally written in 1949) some of what he says about the origins of dogs has been superseded by better information from genetic analysis that was unavailable in Lorenz's time, but most of the rest of his Doggy Psychological Treatise still stands.  And in any case, you'll learn something about how and why your pooches behave the way they do -- and along the way, a bit about human behavior, too.

[Note: If you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]