Los Angeles Review of Books

MY BEST FRIEND BRIAN and I are told that we are insufferable when it comes to food and drink. For us, there is no question that a martini must be made with gin. A vodka “martini” is, properly speaking, not a martini — ­­a wannabe martini, an ersatz martini, but not a martini at all. Brian once quizzed my daughter’s boyfriend about whether the “barbequing” he announced he was about to do was really mere “grilling,” and then offered a detailed disquisition on the difference. My daughter was not amused. (For the record: grilling, just as we suspected.) Amber beer? Don’t get us started.

Adam Rogers, too, has taken the liberty of entertaining and informing people about this subject matter. “The word ‘actually’ is why people don’t have drinks with me anymore,” he confesses in his entertaining and informative book, Proof: The Science of Booze. Like me and Brian, Rogers patiently corrects the errors, the mistakes and misperceptions, and generously cures the ignorance of relatives, friends, and strangers who unwittingly take a seat next to him at the bar. “Actually,” we say, “it’s the yeast, a little-understood eukryotic microorganism in the fungi kingdom, by the way, that is responsible for most of the flavoring of the beer you’re trying to enjoy.” A self-confessed “bar know-it-all,” a man after my heart, Rogers is amusing and instructive, as opposed to just annoying (like Brian), and has distilled his storehouse of historical and scientific information about alcoholic beverages into a valuable book that will enable the reader to appreciate the amazing complexity of his favorite libation, and also qualify him as the liquor world’s next ambassador to the benighted masses.

The title of Rogers’s book gives a good idea of its contents and tone. Not for the Erlenmeyer flask and Bunsen burner set, this book is aimed at the dedicated practitioner, someone who likes a good drink and is curious to know more about how it came to be and how it produces the effects — aesthetic and anesthetic — that it does.

Rogers dispenses plenty of detailed explanations of the chemical and physical processes and properties that go into producing alcoholic beverages, but he leavens his story with amusing anecdotes and smart-ass asides. Rogers visits the scientific annex of a revered drinking establishment on the Lower East Side in New York City, a kind of “sorcerer’s workshop” where they take a sophisticated technological approach to drink, drilling down to the molecular level, all in the name of reinventing the cocktail. Presented with the prospect of a vodka and soda prepared with a carefully calibrated carbonated soda specially designed to produce a certain mouth texture in combination with the vodka, Rogers remarks: “Vodka and soda is a crap drink.” Told by his defensive magician of mixology that customers always prefer the more elaborate version to their usual, Rogers offers no comment. I can tell he disapproves. And rightfully so. For all its scientific wizardry, this is not booze worth drinking.

Rogers’s tour of the science of booze starts with its basic components, yeast and sugar, and an examination of the processes used to harness and refine the ethyl alcohol they produce to create potable liquors. He reviews fermentation, distillation, and aging, and what we know about how the resulting product affects us, first via smell and taste, then through the complex interaction with body and brain. This brings us, inevitably, to the occasional hammer blow of the hangover — a vitally important subject that has largely escaped the attention of the scientific community, undoubtedly because they are busily attending to their Erlenmeyer flasks rather than the painful truths of the practical aspects of inebriation. The eight resulting chapters are like building blocks, one moving logically to the next, each of them full of essential information about how what was poured into your glass got there and what happens once you imbibe it.

Perhaps the most striking lesson of Rogers’s book as a whole is how little we actually know about such a widespread and familiar part of almost every civilization. Indeed, booze is synonymous with civilization, or at least coterminous. Nature spontaneously produces alcohol, for example, in ripening fruit; bears, monkeys, and other animals, and undoubtedly some happy cavemen, discovered Mother Nature’s speakeasy. My dog’s excessive fondness for overripe figs that have fallen to the ground is now clear to me. But the attempt by humans to intentionally harness the natural process of fermentation seems to be among the first interventions of humans into nature, one of the very first technological achievements of our ancestors, bless them. Archaeologists scraping suspiciously wine-like residues on clay shards and other deposits on various vessels have found evidence of fermentation going back as many as 10,000 years. This places intentional alcohol production at the time of the Neolithic Revolution, the advent of large-scale agriculture and the domestication of such animals as the cow, sheep, and dog. Beer followed somewhat later, as the method for extracting the necessary sugars from wheat, barley, rice, and other grains — a harder nut to crack than getting ripening fruit to cooperate. Fermented beverages seem to have been discovered by every civilization, well beyond the Fertile Crescent to China, South America, and elsewhere. Our forebears industriously cultivated these arts, and fermented beverages have been central to religious, cultural, and other aspects of civilization since the beginning of civilization itself.

If the craft of fermentation, and later distillation, has a storied tradition, the science of booze is quite new. Producers of alcoholic beverages have long passed down and carefully guarded the secrets of their trade, but alcohol production was until recently a matter of craftsmanship. And still largely is. Why do certain yeasts behave as they do? How is it that different flavors are yielded by different processes, even by the unique dents and dings in a certain copper still? And where do I find a good cure for a hangover? These questions have been the subject of serious scientific investigation for little more than a century, a mere speck of time in the human experience with booze.

The mysteries begin with yeast. Most people probably think that brewers use a Paul Bunyan–sized equivalent of the familiar little packets sold at the grocery store, pouring the powdery stuff into a vat of some sort of fruit juice or mashed grains. Not so. Different yeasts produce different flavors, sometimes very different from one another. Brewers nurture and guard their yeasts with the care normally reserved for newborn infants. They even pay a lot of money to have their strains of yeast frozen in laboratories, just in case. Rogers tells the story of a Belgian brewer who had an entire new building constructed around his musty old brewing facility (read: barn) so as not to disturb the wild yeasts living in the rafters responsible for the specific flavor of the product of the spontaneous fermentation process used to make lambics. The distinct banana and clove scent of Hefeweizens are a result of the specific yeast used. Rogers visits a lab where he is presented with an array of different style beers, and only after he tastes them finds that they all used precisely the same recipe of malts and hops, the only difference among them being the yeast.

Although yeast has been employed in fermentation for thousands of years, its properties were magical to the craftsmen themselves, who ritually repeated the steps of their art without understanding the process. They used some of the old wort to start a new one and thereby re-propagated their yeast culture like a sourdough starter, but after about 8,000 years of experience with fermentation, it was only in the late 1850s that we began to have a scientific understanding of the process and yeast’s role in it. The father of modern chemistry, Antoine Lavoisier, figured out that it was sugar that was converted into ethanol, but he missed yeast’s pivotal role in the process; perhaps he would have discovered the indispensible role of the little fungus if the French Revolution hadn’t cut off his research, along with his head. It was left to Louis Pasteur, called in to consult on some bad batches of hooch, to realize yeast’s role. Ethyl alcohol, he discovered, is a waste product expelled by yeast after sugar is metabolized. Not a very romantic outcome.

Fermentation, distillation, and aging each have their own unanswered questions. Distillation is comparatively new, dating back a couple thousand years. Rogers tells the story of Maria the Jewess, a talented alchemist residing in Alexandria around the first century AD who is credited with inventing the first still, but in the name of science. The first stills we know of dedicated to distilling alcohol for the purpose of drinking had to wait until about 700 years ago. Any fermented product can undergo the process of distilling out the alcohol and leaving the pesky water behind. For example, wines or other fermented fruit juices produce the beginnings of brandy, cane juice becomes proto-rum, and what is effectively beer without hops moves a step closer to whiskey. Much ingenuity has gone into building and maintaining impressive contraptions for distillation, and the distillers are as jealous and solicitous of their apparatuses, with their unique twists and turns of copper, as brewers are of their yeast.

Only distillation produces “fire water” of various types, including vodka. Vodka in its pure form, that is with any impurities removed through filtration, is simple ethyl alcohol. Since by “impurities” I mean flavor, you can see that Rogers and I are in agreement on vodka, at least as a standalone venture. When offered a sampling of scientifically ultra-quickly aged liquors, Rogers skips the citrus vodka, “because come on.” Proper aging is what creates many alcoholic beverages worth being called booze. Aging can come in a number of forms, but perhaps most famous is the aging in wood familiar to wine and whiskey, and increasingly with specialty beer and other liquors. Usually done in charred barrels, mostly oak, the aging of fermented and distilled spirits allows them to mature and gather flavors from the wood itself. Once again, the processes of aging are only now beginning to be understood. I was cheered to learn that scientists have isolated and identified compounds derived from the wood aging that are related to vanilla, meaning that I’m not imagining tasting these flavors in my bourbon whiskey. Or at least I might not be imagining them. Ditto for the peatiness of certain Scotch whisky (not “whiskey”), since peat is used in charring the barrels at some distilleries. And even perhaps the “briny” bouquet and flavor some of us claim to detect in Islay whiskies: whereas whiskies such as Kentucky bourbon aged in warehouses lose as much as two percent of their volume every year they stay in the barrel (the loss known as the “angels’ share”), their cousins across the Atlantic actually gain some volume when stored outside by the seashore.

Having spent five chapters on the production of booze, Rogers turns in the last three to its consumption. Our lack of scientific knowledge about something so important as smell and taste is downright scandalous. Granted, there are deep philosophical perplexities. We are all familiar with the question of whether you and I are seeing the same thing when we see something we call “green.” A trifling matter next to whether we are smelling or tasting the same thing when we smell or taste such things as cherries, ripe stone fruit, or vanilla in our glass. Booze turns out to play a proud role in the science of smell and taste because so many complex compounds are carried along with ethyl alcohol (and its cousins — think of perfume).

Alcohol itself is quirky, activating receptors for both sweet and bitter and also acting as an irritant, lighting up the perception of heat, hence the “fire” in “fire water.” Apparently it also tastes bad, at least until our bodies learn to associate it with its pleasant psychotropic effects, thus literally educating our palates. But education has its limits: even experienced wine connoisseurs can have a difficult time identifying wines, with experts barely outpacing amateurs in one study Rogers cites. Is Robert Parker making it up as he goes, or perhaps he conned himself into believing what he says? Maybe. But as with colors, most people can be trained to recognize distinct smells and tastes and agree to call them something in common. (It turns out that the familiar wine wheel, now copied for beer and other libations, that identifies families of flavors and arrays them in a nifty circle and thereby gives us a common language for flavors, was invented by a colleague of mine at the University of California, Davis. I’ll have to look her up.) This shared language then enables scientists to identify the specific compounds that produce a given flavor. We’re finally making progress.

What happens once booze makes it past our noses and tongues? Surprisingly, we really don’t know. “After 10 million years of ethanol consumption, 10,000 years of dedicated production, and over a century of focused scientific research,” Rogers reports, “human beings still aren’t totally sure what relatively small amounts of ethanol do to the body.” Unlike heroin, say, there is no specific receptor in the brain to which ethanol attaches. Alcohol seems to have a complex effect on the brain, at once a stimulant and a depressant. But its numbing effects are more predictable. So predictable, in fact, that computers have been programmed to detect the slurred speech of the inebriated, and a group of German scientists have built a kind of speech breathalyzer using the inimitably named (and very Teutonic) “German Alcohol Language Corpus.” One team got it right about 75 percent of the time. Not bad, but not good enough.

Rogers’s last chapter, on hangovers, proves that everything you thought you knew about hangovers is wrong, or at least incomplete. Yes, the dehydration that comes from excessive consumption has adverse effects, but alcohol takes its toll with or without dehydration. Drinking plenty of water is a good idea, but will not forestall the inevitable. The best existing theory to date is that hangovers are a kind of inflammatory response by the body due to elevated levels of molecules called cytokines, which are used as signals by the immune system. If this explanation pans out, then we are on the way to a potential cure for the hangover. But Rogers, despite his delight in science and perhaps even greater delight in booze, for once moralizes in his book by pointing out that such a cure would carry with it moral hazard for the drinker.

Proof: The Science of Booze is itself proof that scientific knowledge can enhance one’s enjoyment of activities as old as civilization. If not the enjoyment of the guy who makes the mistake of sitting next to you at the bar.


John T. Scott is a professor of political science at the University of California, Davis. His office overlooks an enormous brandy still operated by the folks in Davis’s famous department of viticulture and oenology, who for some reason have yet to consult him on his scientific knowledge or even invite him over for a dram.

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