If you drive down Interstate 82 in southeastern Washington State, or along the agricultural byways of Oregon’s Willamette Valley or Idaho’s Treasure Valley, you might notice a strange plant growing alongside the road. Its tall, leafy “vines” stretch upward nearly 20 feet in gigantic V shapes on trellises of wood and sturdy string. These are hop plants.
Hops (the cones or flowering parts of the hop plant, Humulus lupus) have been used throughout history for a variety of purposes, the best known of which is the flavoring and preservation of beers and ales.
How important are hops? We live in a thirsty world! An estimated 52 billion gallons of beer were produced worldwide in 2013 and worldwide hop acreage was 114,276. Acreage in 2014 is expected to top 118,000. Germany and the United States are the top two hop-growing nations.
Hops in the U.S.
In 2014, 39,272 acres of hops were grown in the United States. While the production of hops began on the East Coast, a variety of factors gradually moved production westward. Today, 98 percent of U.S. hops are grown in the Pacific Northwest.
Hops can be successfully grown in a variety of climatic conditions. Washington is the No. 1 hop-producing state, growing about 74 percent of the nation’s hops in the hot, dry conditions of eastern Washington’s Yakima Valley. Oregon is the second largest hop-producing state, growing about 15 percent of our hops in the rich soil and abundant rainfall of the Willamette Valley. Idaho ranks third, accounting for about 10 percent of the U.S. acreage, some in the cool, moist northern Idaho panhandle and the rest in the warmer, arid Treasure Valley of southwestern Idaho.
With the rise in popularity of “craft beers” (small batch, often regionally exclusive), many states outside the Pacific Northwest are now growing hops. Michigan and New York are now the fourth and fifth largest hop-producing states, respectively. Since hops can be grown pretty much anywhere between latitudes 35 and 55 degrees, it is safe to assume that most continental U.S. states have or will soon have hop yards.
How Hops Grow
Hops are most often propagated from rhizomes, which are planted in hills roughly 4- to 6 feet apart within rows approximately 15 feet apart. They are grown under a trellis system utilizing heavy-gauge wire or other support material suspended by poles. Most hop yards use drip irrigation.
Each year in early spring the hop rhizome or crown begins to produce shoots. The shoots become stems (called “bines”). The grower selects a few vigorous bines per hill and trains them to the support wires/twine. The bines grow rapidly (sometimes several inches to a foot per day) in a clockwise direction around their wire support, following the sun. By early summer, they can reach 18 feet in length and begin to grow lateral branches. After summer solstice, hop plants respond to decreasing day length by producing flowers. These flowers first appear as small “burrs,” each of which eventually develops into a hop cone. The stem dies back to the crown after the hop cones mature.
Hop Harvest and Use
When hops are mature (late summer or early fall), they are harvested by hand or machine. Automated picking machines are common in larger commercial operations. With conventional tall trellises, the bines are cut at their base and from the overhead support wires, and transported by truck or trailer to stationary machines that remove the cones and separate them from the bines, leaves and stems.
With low-trellis systems, mobile picking machines are used to remove cones from plants in place, leaving most of the bines and crop debris in the field. Cones are then cleaned to remove small-sized pieces of stems and leaves.
Harvested hop cones are dried to 8 percent to 10 percent moisture content in forced-air kilns, some of which are quite large and technologically savvy. Drying is essential for long-term storage, since it reduces spoilage from decay organisms and reduces the possibility of combustion in the cones.
Once established, the hop plant will produce an annual crop of cones indefinitely. Historically, industry practice has been to rotate plantings every 10- to 15 years, as influenced by disease and other pests that can cause yields to decline. Today, rotations are more likely to take place every 5- to 10 years due to new and different cultivars coming into demand.
What comes next? That’s the good part. Hops are either pelletized or used whole in the brewing of one of the world’s most popular beverages. So next time you hoist a mug of your favorite beer or ale, thank a hop grower!
Is there an unusual crop that grows in your area?