The Drunken Botanist: The Plants that Create the World's Great Drinks (7 page)

Bugs in the brew? It is an age-old problem. Fermentation takes place in open tanks by necessity; otherwise, the pressure from the carbon dioxide would build to dangerous levels. But when a vat of fruit juice or grain mash is left to brew in an old barn or warehouse, bugs will surely find their way in. This is not always such a bad thing: lambic brewers in Brussels realize that some of their best strains of yeast come from insects falling from the rafters. In fact, yeast produce esters in order to attract insects, hoping they will pick up the yeast and move it around. This makes bugs unwitting accomplices in the dance between sugar and yeast.

 

BARLEY

Hordeum vulgare

poaceae (grass family)

I
magine a world without beer, whiskey, vodka or gin. Impossible! Yet it is no exaggeration to say that without barley, they wouldn't exist. Among grains, barley is uniquely well suited to fermentation, so much so that it can even help with the fermentation of other grains—making it possible to coax alcohol from the most unlikely of sources.

To understand the near-miraculous powers of barley, consider first the fact that cereal crops—barley, rye, wheat, rice, and so on—are not bursting with fermentable sugars the way apples or grapes are. Grains are packed with starch, which is a kind of storage system that allows plants to save the sugar they make during photosynthesis for some later use. To make alcohol from grains, the starch has to first be converted back to sugar.

Fortunately, it takes nothing but water to persuade a plant to perform this trick. Each individual grain is, after all, a seed. When that seed germinates, it's going to need some food to sustain it until it's big enough to put down roots, spread out leaves, and make its own dinner. That's what the stored sugar is for. All a brewer needs to do is to get the grain wet—a process called malting—which starts germination and prompts enzymes inside the grain to break down starch into sugar to feed the tiny seedling. Then it's simply a matter of adding yeast to devour the sugar and excrete alcohol. Simple, right? Not exactly.

Distillers learned the hard way that not every grain gives up its sugars so easily. That's where barley comes in: it possesses unusually high levels of the enzymes that convert starch to sugar. It can be mixed with another grain, like wheat or rice, to jump-start the process in those grains as well. For that reason, malted barley is the brewer's best friend—and has been for at least ten thousand years.

Barley is a type of tall, very tough grass that isn't bothered by cold, drought, or poor soil, making it widely adaptable around the world. In the wild, the spikelets of grains shatter and drop as soon as they are ready to germinate, but some enterprising early humans noticed that occasionally a barley plant would hold tightly to its grains. This was an ordinary genetic mutation that might not have had much benefit for the plant, but it was one that people liked: if the grains stayed on the stalk, they were easier to harvest.

And that is how the domestication of barley happened. People selected seeds that possessed a trait they liked, and those seeds went around the world. Barley originated in the Middle East, making its way to Spain by about 5000 BC and to China by 3000 BC. It became a staple grain in Europe. Columbus brought it to America on his second voyage, but it wasn't established in the New World until the late 1500s and early 1600s, when Spanish explorers took it to Latin America and English and Dutch settlers brought it with them to North America.

It is easy to imagine the ancient, happy accident that led to the invention of beer. Picture a bucket of barley left to soak overnight to soften the tough outer husk. Wild yeast would have found its way into the bucket, and someone would have thought to taste the strange, foamy mixture that resulted from the yeast going to work on all those sugars. There it was: beer! Yeasty, bubbly, mildly intoxicating beer. The priorities of people in the waning years of the Stone Age must have undergone a rapid reshuffling as society organized itself around the need to reproduce this glorious mishap on a larger scale. (Is it any wonder that the Bronze Age, with its large metal tanks, came next?)

By archeological standards, it took no time at all for sophisticated beer-making techniques to develop. Patrick McGovern, a University of Pennsylvania Museum archaeologist who studies the history of fermentation and distillation, analyzed the residue on pottery fragments found at the Godin Tepe site in western Iran. He detected the residue of barley beer on drinking vessels and was able to date it to 3400 BC to 3000 BC. He believes that the beer was probably not terribly different from what we drink today, except that it might not have been as finely filtered. Cave paintings and markings on the pottery depict people sitting around a large pot of beer and drinking through long straws. The straws were aimed at the middle of the brew so that whatever sediment sank to the bottom or rose to the top could be avoided.

Beer making grew more sophisticated in Roman times. Roman historian Tacitus, describing German tribes, wrote that “for drink they use a liquid made of barley or wheat and, by fermentation, given a certain likeness to wine.” It wasn't long after that, perhaps as early as 600 AD, that people in barley-growing regions realized that just like wine and cider, beer could be distilled into a much more potent spirit. By the late 1400s, whiskey—which was then called aqua vitae, a generic term for distilled spirits—was being made in the British Isles.