Sprout damage up in Washington wheat

Matthew Weaver

Capital Press

More samples of Washington-grown wheat are showing evidence of sprout damage this year, industry and state officials say. But the issue has as much to do with the test for sprout damage as the quality of wheat, they say.

SPOKANE VALLEY, Wash. — Evidence of sprout damage has been found in 25 to 30 percent of Washington state wheat samples that were tested this year, the state Department of Agriculture Grain Inspection Service reports.

Usually the office runs 100 to 200 samples through a falling number test each year. This year, the office has run roughly 11,000 tests looking for evidence of sprout damage, which hurts the quality of wheat, said Mark Marshall, office supervisor of the Grain Inspection Service lab in Spokane Valley, Wash.

“The rain hit a lot at the wrong time,” he said.

Glen Squires, CEO of the Washington Grain Commission, said significantly more sprout damage has been found in his state this year due to frost and rains, but Oregon Wheat CEO Blake Rowe said it has not been an issue in his state this year. A dry summer caused reduced yields in the crop, but quality has been “quite good,” he said.

Idaho Wheat Commission Executive Director Blaine Jacobson said there have been only a few reports of sprout damage in his state.

The falling number test is used to measure wheat quality, which sprout damage impacts. The test involves grinding a small sample of grain and mixing it with water to create a paste. When placed in boiling water, the slurry thickens. If the enzyme alpha amylase, which is associated with sprout damage, is present, it begins to consume the starch, reducing the thickness.

A small, weighted plunger passes through the paste. The test measures the time it takes for the plunger to fall, plus a 60-second initial stirring.

The industry standard for soft white wheat is 300, meaning it takes 300 seconds for the plunger to fall. Numbers below that generally indicate lower quality wheat that could run into processing problems. Farmers receive a reduced price for wheat that falls below that standard. Discounts vary according to grain elevator, but are often based on how far below 300 the wheat tests.

The Pacific Northwest wheat industry has criticized the test for its inconsistency, leading to discussions of developing an alternative method of testing for sprout damage.

“We would welcome a test that was less variable, but nobody has come up with anything that’s better,” Rowe said.

“We still need to move to a faster and more consistent test,” Jacobson said.

Due to the variability of the test, which cannot be repeated and can differ depending on sample, Jacobson encourages growers to seek a second test.

“If you’re in the borderline, just under 300, it’s worth a re-test, because it might come up, but it can easily go down, too,” Marshall said. “If you’ve got 150, you’re not going to get 300.”

Squires expects a new testing method to be a topic at the U.S. Wheat Associates and National Association of Wheat Growers joint board meeting in Portland, Ore., in November. It would have to be approved by the Federal Grain Inspection Service, he said.


Share and Discuss


User Comments