WSU Prosser hops research could help future crops

Tri-City Herald staff writerJune 16, 2013 

The beer Ruth Henderson brews may help improve the quality and future of Washington hops.

Her brewing at Washington State University’s agricultural center in Prosser will help researchers figure out how water, nutrition, disease and pests affect beer quality. It’s one piece of a large project that aims to help a growing industry improve quantity and quality.

Washington’s hops were worth about $157 million in 2011, according to the U.S. Department of Agriculture.

Demand for hops is climbing thanks to the growth of craft breweries, which use up to 10 times more hops than traditional brewers to make the same amount of beer, said Doug Walsh, a WSU entomologist working with the hop project at the Irrigated Agriculture Research & Extension Center.

Now Washington farmers are planting more hops to keep up with demand, he said. Most are planted within a 40-mile radius of Prosser.

Washington grows more than 75 percent of U.S. hops, according to the Hop Growers of America. Washington is second only to Germany in hop production.

Last year, state farmers harvested about 24,200 acres, up about 6 percent in five years, according to the USDA. Those acres produced about 49.6 million pounds of hops. At WSU’s Prosser center, about 26 acres are dedicated to hop research.

In different blocks, WSU researchers are experimenting with various levels of water and fertilizer. Other blocks are being grown with different levels of pests and disease. Hop plants are bushy at the ground, and send tendrils of vines up a coconut husk rope as they grow, until the vines reach the top of the trellis.

Walsh said the vines can grow more than a foot a day, curling around the rope as the sun moves.

The perennial plant has a woody crown underground, he said. While the plant can last 50 years, most farmers take them out after five to seven years because of the changing industry.

Hops like Mid-Columbia’s long days and cool nights, he said.

Harvest may start around the first week of September. Then, the vine will be cut off at the trellis, and will go through a machine that removes the cones from the vine. The cones are then dried in a kiln.

At the research center, a chemist analyzes the hops before they’re used to brew a batch of beer.

For her research, Henderson, a WSU post-doctoral research associate, splits a 15-gallon batch of wort — unfermented beer, which includes water and barley sugar — into three, 5-gallon batches.

It’s important for the base to be the same, so that researchers can test how the different hops change the end product, Walsh said.

Like craft brewers would, Henderson adds enough to make the alpha acids — the source of the bitterness — consistent.

About a month ago, Henderson went to Sierra Nevada Brewing Co., a flagship brewer of the American Craft Brewers Association, in California to learn more about beer making.

Since then, she has changed the her process, discovering that her brews may have been exposed to too much oxygen after fermentation.

The finished beer heads to a sensory scientist at WSU Pullman, who looks at how beer drinkers like it.

Walsh said WSU researchers have already determined that cutting back irrigation water radically reduces the quantity of hops grown.

“Any amount of water stress, and the yield drops like a rock,” he said.

And they found that beer drinkers did not like batches made with hops damaged by spider mites or downy mildew.

But consumers seemed to like the beer brewed from hops that had slight damage from powdery mildew even more than the hops with no damage, he said.

The hop research project is being paid for by a USDA Specialty Crop block grant, a Washington State Department of Agriculture’s Specialty Crop block grant, the National Hop Research Council, the Washington Hop Commission and the American Craft Brewers Association.

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