Producers and other workers in the wheat industry must remember the critical importance of keeping various classes of wheat separate, says South Dakota State University Seed Testing Laboratory Manager Brent Turnipseed.
"Right now in South Dakota, we have three different classes of wheat being sold, and all three need to be kept separate from one another," Turnipseed said. "It's critical that people working with these grains keep them separated, especially hard white varieties from hard reds."
The three classes are hard red winter, hard red spring, and hard white wheat (HWW). Since each class has its own end uses, and each variety has its own baking and milling qualities, when classes are blended or mixed, the wheat loses value.
"You do not want to mix contrasting classes of wheat at all, because the margin of error is very small," he said. "The wheat will become a lower grade quickly. It must be avoided."
Until last year, hard white wheat had been contrasting, but now, it is just wheat of another class in the hard red winter and spring categories. Amber durum wheat is contrasting to hard red winter, hard red spring, and hard white wheat, said Turnipseed.
When wheat classes are mixed, and the second grain makes up more than 10 percent, the grain will be graded as U.S. Mixed Wheat, which is a separate class and less desirable.
Mixed wheat most often is sold as livestock feed.
Producers who want more information can contact South Dakota's only licensed grain-grading facility, Aberdeen Grain Inspection, where wheat can be graded. The USDA's Grain Inspection, Packers & Stockyards Administration Web site includes information about U.S. grain standards. Visit www.gipsa.usda.gov and then click on the "grain, rice, pulses" link, then on the "standardization and quality" link to see the standards for wheat.
Turnipseed said the potassium hydroxide test is the best method for determining whether wheat is a red or white variety. It is quick and easy to run. "Sometimes the hard white wheat varieties, especially those used in the Great Plains, look like a very light-colored red wheat," he said. "The potassium hydroxide test makes it easy to distinguish the two."
SDSU AgBio Communications