The Drunken Botanist: The Plants that Create the World's Great Drinks (42 page)

It is difficult to appreciate the storage problems early brewers faced. But just imagine tapping into the last keg in the basement at the end of a long, miserable winter only to find that bacteria had spoiled it months ago. Settlers arriving in the New World on the
Mayflower
may have encountered this very problem:
Mourt's Relation,
an account of the Pilgrims' arrival, suggests that a shortage of beer forced them to make an unplanned landing at Plymouth: “We could not now take time for further search or consideration: our victuals being much spent, especially our beer.” With no way to disinfect fresh water, and nothing but salt water all around them, beer might have been the one beverage keeping them alive on their long journey. Once it was gone or ruined, they would have been in real trouble.

But hops came along and turned beer into a far superior product. The hop vine's cones (clusters of female flowers) are laden with yellow glands that secrete lupulin, a resin containing acids that help make beer foamy, give it its bitter taste, and extend its shelf life. These so-called alpha acids are so critical to good beer making that hops are rated according the amount they produce. Aromatic hops are lower in alpha acids but produce delightful flavors and aromas, while bitter hops are higher in alpha acids, make the brew last longer, and contribute more bitterness to counteract the yeasty flavor of the malt.

These vigorous, sturdy vines are closely related to marijuana; there is a vague family resemblance between the dank, sticky cannabis flower buds and the equally sticky and fragrant cones of the female hop vine. Like cannabis, hops are dioecious. Females can grow their highly prized cones without a male around, but they can't set seed and reproduce. Hop farmers select female vines and scour their fields for any uninvited males, which they promptly evict. They don't want the females impregnated, because brewers won't buy seed-infested cones.

Hops can't grow just anywhere: these tall, perennial vines require thirteen hours of sunlight per day while they are growing, and that can only be found in a narrow band around the world at 35 to 55 degrees north and south latitude. That means they are abundant in Germany, England, and elsewhere in Europe. In the United States they are grown mostly in the West: hop farming was pushed westward as powdery and downy mildew diseases made it impossible to grow the vine in eastern states. The hops industry had another advantage in Oregon and Washington: farmers survived Prohibition by shipping dried hops to Asia.

In latitudes 35 to 55 degrees south, hops grow in Australia and New Zealand, and in the north they are grown China and Japan. Attempts have been made to grow them in Zimbabwe and South Africa as well, but without the optimal day length, streetlights have had to be installed in hop yards. Meanwhile, optimistic botanists are working on a day-length neutral hop variety that doesn't object to longer or shorter days during its flowering season.

During their growing season, hops are astonishingly vigorous, rising six inches in a single day. The vines stretch away from the central stalk during the day; at night, they wrap themselves around wires or other supports. “You walk through the fields in the late afternoon, and you'll see all these vines reaching out at forty-five degree angles,” said Oregon hop farmer Gayle Goschie. “Then you come out the next morning and they're wrapped tightly around the trellis again.” They spiral around the trellis in a clockwise direction, which has inspired a couple of botanical urban legends: one is that they grow counterclockwise in the Southern Hemisphere, and the other is that they grow clockwise to follow the sun from east to west. Neither is true. Like left-handedness, they are simply born with a genetic predisposition to grow clockwise, no matter where they are relative to the sun or the equator. (Botanists who study “twining handedness” have discovered that hops are unusual in their proclivity to twine in a clockwise direction; 90 percent of all climbing plants prefer to go counterclockwise.)

Hops don't just climb wire trellises. Tiny barbs on the vines make it possible for them to climb trees or other plants as well. Romans thought the vine killed trees by strangulation and named it “little wolf,” which explains the origin of the plant's genus,
Lupulus.

Farmers are quick to point out that hops are not a very nice vine. Darren Gamache, a Washington grower, knows what it's like to pick them by hand the way his grandparents did. “The vines have these rough little bristles that are very abrasive, and will even leave welts. Especially when it's hot outside, and you've got salty sweat running into open wounds—it's really uncomfortable,” he said. “And a lot of people have an allergic reaction to them.” Most hops today are picked by machine for this very reason.

The danger is not over after harvest: freshly picked hops heat up the way a compost pile does and have been known to catch fire. When large bales of hops are packed into storage, they can actually spontaneously combust and burn a warehouse down. Fires at hop yards were a frequent occurrence in the Pacific Northwest's early hop-growing days.

Brewers, for the most part, have little idea that hop farmers must endure scratchy vines, fight warehouse fires, and chase love-struck males out of their fields to get the crop to market. Hops generally aren't even recognizable as cones by the time they get to the brewery: they are pressed into pellets and shipped in vacuum-sealed bags. A few brewers use green hops straight from the fields in a seasonal beer around harvest time; to experience freshly picked hops, look in the fall for “fresh hop” or “wet-hopped” brews.

Hop kiln
: Also called an oast house in England, these distinctive barns with cone-shaped towers were used to dry hops when they came in from the fields. The hops would be spread on a frame suspended in the upper part of the tower, and a fire would be lit underneath to dry the hops. They could then be bagged and stored in the barn.