Amber Hauvermale and her team of researchers greeted wheat farmers last summer with cake and bread during the industry’s annual field tours.

Some baked goods were the usual high quality customers have come to expect.

Others, however, were soggy or broken, because they were made with flour from wheat that had a low falling number — starch damage.

The demonstration was a good way for growers to see the impact of starch damage on the final product, said Hauvermale, a Washington State University associate professor and project leader of an industrywide effort to develop a new rapid test for wheat quality.

“The bread doesn’t bake right, or it doesn’t slice right, or you’ve got falling cakes and your product doesn’t look the way it’s supposed to or what people expect,” she said of wheat that has starch damage.

What falling number means

A falling number test measures the amount of pre-harvest sprouting and alpha-amylase, an enzyme that breaks down starch.

Small bakeries can often pivot when they encounter starch damage, Hauvermale said.

“But if you have an assembly line and you’re turning out thousands of units of a product and you have a problem, you can imagine, it becomes a nightmare really quickly,” she said.

A old test

Farmers call the existing, 70-year-old falling number test “slow,” “complex,” “cumbersome” and unreliable. They want a test that’s faster and will produce an accurate result every time.

Working with EnviroLogix, a Portland, Maine, company that develops rapid diagnostic tests for the agricultural industry, the research team tested thousands of prototype rapid tests.

The effort is supported by an $835,000 grant from the Foundation for Food and Agricultural Research and $1.2 million from other collaborators.

They hope to develop a device that’s commercially available to grain elevators and farmers and will provide fast, accurate and consistent results.

“Once that happens, we will have greater opportunities for learning how to manage the crop, either before or after harvest to limit starch degradation in the kernels,” said Leslie Druffel, outreach coordinator for the McGregor Co., a Washington-based agribusiness company.

Why it matters

Low falling number indicating starch damage can typically show up in dryland wheat in years with variable weather, Druffel said.

When a grower takes wheat to the local elevator, it gets a quality grade. The farmer leaves with a level of expectation whether he will be able to sell that wheat at full price or at a reduced price for not meeting key standards such as test weight, moisture level or protein percentage.

Discounts usually amount to a few pennies per bushel for each category, Druffel said.

But falling number test results for a crop may not be available to growers until harvest has been completed, sometimes surprising them with “significant, substantial” discounts on their wheat.

The industry standard is 300 — the number of seconds it takes a stirrer to fall through a slurry made with water and wheat meal. The thicker the slurry, the longer it takes the stirrer to fall. This results in a high falling number.

Thin slurries due to starch damage caused by the alpha-amylase enzyme result in a low falling number.

Discounts start at 25 cents per bushel.

An added problem is sometimes the falling number test is inconsistent.

“A grower relayed to me that after this year’s harvest, he received a (falling number) test result of 296,” Druffel said. “That meant everything he delivered would be discounted by 25 cents per bushel when sold.”

The farmer asked for his wheat to be re-tested, since no one else in his area was seeing a low falling number. The result came back well over 300.

“His comment to me was, ‘The inconsistency of test results is very concerning because these are heavy discounts being levied,’” Druffel said.

In 2016, losses because of starch damage in the Pacific Northwest were “staggering,” said Alex McGregor, chairman of the McGregor Co. He estimated low falling number test results cost farmers $140 million that year.

“The inadequacies of the falling number test, and the real-world impact of its shortcomings on the thousands of farm families we’ve worked with over the years, have been major concerns of mine for a very long time,” he said. “Farmers had little defense against potential calamities knowing the current tool would be inaccurate and slow. We’ve not let up on finding a better test because one falling number punch in the gut is enough.”

Side by side

Researchers last summer ran the new rapid test in tandem with the old test in three locations: the HighLine Grain Growers facility in Coulee City, the Wheat Marketing Center in Portland and at WSU in Pullman.

“We were slammed with samples,” Hauvermale said of the HighLine testing.

The old industry standard falling number test takes about 12 minutes per test from start to finish, which includes setup and weighing.

The rapid test takes about 5 minutes, and up to six samples can be run at one time.

It involves mixing milled wheat meal with water and shaking it for 30 seconds, then spinning it in a centrifuge for another 30 seconds.

The sample is then incubated with a chemical substrate in a test tube for 1.5 minutes. A “dipstick” strip is added for 3 minutes, and then read using a rapid reader.

Hauvermale estimated the WSU lab ran about 1,500 rapid tests, which she said was “way easier” than running 1,500 old falling number tests.

In general, the rapid test was “pretty good” for predicting lower or higher falling numbers under normal conditions, Hauvermale said.

EnviroLogix set parameters for test performance, with a range of acceptable variation, Hauvermale said. Up to 90% of tests fell within those parameters.

Those parameters are broad, she said, so the next step is improving the test’s calibration.

If the test can be refined enough, perhaps it could replace the existing system, said Paul Katovich, the CEO of HighLine, which is in Waterville, Wash.

“That’s the ultimate goal, to have something that’s fast and functional,” he said.

Quality assuranceIdeally, a quick test would be similar to a traffic light, Katovich said.

Red would mean, “Holy smokes, this stuff is bad,” yellow would mean, “This stuff isn’t terrible, but you should probably bin it separately,” and green would mean, “Full steam ahead,” he said.

“Something that would be functional at the truck dump,” he said. “In a perfect world, it would be a whole-grain analyzer so you wouldn’t destroy the sample when you test it, but that has proven to be very elusive.”

The old falling number test assures export customers that quality specifications are met, Katovich said.

The industry standard, a falling number of 300, “more or less guarantees, when ships get to their destination, they’re not buying a product that becomes useless in the process,” he said. “We hold ourselves to a standard that no one else in the world does.”

The falling number test is “nothing new” to co-ops in wheat country along Highway 2 in Washington state, Katovich said.

By and large, the advent of low falling number test results is an isolated event and impacted by geography, elevation and temperature changes, he said.

HighLine’s geographic footprint lends itself to more susceptibility, he noted.

“We have some pockets of it every year … but we get better and better at making these types of problems go away,” Katovich said.

That means blending the problems that can be blended out, he said. For the crop problems that can’t be managed by blending, the company separates the wheat and markets it in other ways, such as into feed markets.

“Our job is to make sure that the product that reaches Portland (for export) meets the standard,” he said.

“The year that changed everything was 2016, when everybody had a problem,” he said.

Better breeding

Katovich suspects the reason lower falling numbers have become more prevalent is largely varietal.

“We need a variety that is so vigorous that it comes up in the driest of conditions, so it has to have a quick trigger,” he said. “As we sort for those things, I think we inadvertently brought in this falling number weakness issue. … This really wasn’t an issue 20 or 30 years ago.”

With all of the attention, Katovich hopes “that we end up breeding our way out of this, but that’s hard to do.”

For wheat breeders, that’s a tall order.

“It’s been a real bear to figure out how to evaluate for falling number propensity, because everything is so slow and the environmental effects are so great, but I think we’ve come up with a way this year,” said Kim Garland-Campbell, club wheat breeder for the USDA Agricultural Research Service in Pullman.

Hauvermale’s team can identify locations that could present potential problems. Garland-Campbell then runs falling number tests for those locations, checking alpha amylase and weather data to gain clues about the genetics of a variety.

“I want to be able to tell the grower accurately, ‘Here is what this line will do — it’s a good line for falling number or it’s a bad line for falling number,’” Garland-Campbell sad.

‘It takes a village’

Camille Steber, a USDA molecular geneticist, induced late-maturity alpha amylase and pre-harvest sprouting in the field and greenhouse to have more than 1,000 samples per year in 2023 and 2024 “that we know have one problem or the other,” to compare the rapid test to current screening methods.

Falling number is difficult to study and quantify, Steber said.

First, there’s a fair amount of variation in test results. However, progress has been made since 2016 to standardize results, including corrections for grain moisture content and the atmospheric pressure.

Second, the trait is also affected by the environment. “We still don’t know definitively all of the environmental ‘triggers’ that can cause falling numbers to fall,” Steber said. “More work needs to be done to understand all of the causes of variability.”

Also, because the falling number test is slow and complicated, it “limits our ability to analyze large quantities of samples in a given year,” Steber said.

“Determining falling number accurately requires great care,” she said. “It takes a village.”

EnviroLogix: ‘Pretty pleased’

EnviroLogix wants to provide a convenient tool that anyone could use with limited training, in order to make a quick decision during a busy harvest, said Adam Johnson, senior manager of the research and development rare reagents group.

“We were pretty pleased with this prototype performing as well as it did,” Johnson said. “These are all folks who received a single training session from us, and then just kind of ran with it because harvest was going, the samples were pouring in, and they went to it. We were very happy with the results.”

Hauvermale, Steber and USDA ARS research geneticist Alison Thompson will provide a demonstration of the rapid test at WSU’s Wheat Academy in December.

Hauvermale and Thompson have already released a series of articles about the history and management of falling number in industry magazine Wheat Life. A Crops and Soils magazine article offers a method to identify the stage when developing grain may be impacted by problem weather.

The information will be available on WSU’s Small Grains website.

In interviews with industry members, they found “communication deserts” about what falling number is and its implications.

“We’re trying to figure out how to close those communication loops,” Hauvermale said.

They’re looking to better understand a variety’s performance on a field scale, Hauvermale said: If farmers have repeated problems, what varieties are they using and where are they located?

Falling number will always be measured, said Katovich, the HighLine CEO. It’s too important.

“The quality signal that the falling number test gives the buyer is a primary component to knowing whether or not they can make the intended products,” he said. “Any alternative to the FN test would have to prove the same thing to the buyers.”

Katovich called this summer’s beta testing “a great start.” The rapid tests haven’t hit the bullseye yet, but that’s what the scientific method is for, he said.

“What we want is something that’s not as variable and is faster,” he said. “I think we’re asking a lot, but American ingenuity has solved a lot of problems, so I’m hopeful that we get there.”

Falling number at a glance

• The falling number method to test for alpha-amylase activity was first published in 1964 by Herald Perten, a cereal chemist from Sweden.

•A “falling number” is the number of seconds it takes a stirrer to fall through a slurry or gravy made from wheat meal. The thicker the slurry, the longer it takes the stirrer to fall, which results in a high falling number. Thin slurries are due to starch degradation by the alpha-amylase enzyme and result in a low falling number. Flour with degraded starch yields baked products like cakes, breads, and cookies that are sticky and misshapen, which are less marketable to consumers.

• Why has the falling number metric of 300 seconds become so difficult for PNW farmers to meet in the last 10 years? Research to date suggests there are two culprits: changing weather patterns resulting in pre-harvest sprouting (PHS), which is sprouting of grain due to rain before harvest, and varieties susceptible to late maturity alpha-amylase (LMA). LMA is the result of a cool, wet period during the early dough development stage of wheat.

It is unclear if susceptibility to LMA has always been present in PNW varieties and the variable weather patterns that cause this problem just didn’t occur, or if susceptibility was introduced at some point in a germplasm exchange. Either way, incorporating resistance to LMA and PHS is a focus for PNW breeders to help mitigate these problems.

Wheat Life articles

Reaching a new landmark

A falling numbers fact-finding mission

From elevators to export centers

Part 3: Where do we go from here?

Falling number

this year

This year, “weird weather” in May, with freezing temperatures, resulted in some samples that had lower falling numbers that don’t appear to be caused by alpha amylase, Amber Hauvermale said.

“It’s a new thing, or something maybe that has been around for forever that we just really haven’t had a chance to see it yet,” Hauvermale said. “With the new test, we were able to suss that out a little bit more. We don’t really know what the implications are of that, or how often it happens, or anything like that.”

In general, the overall crop was “really healthy,” she said.

“I have not heard of major problems any where,” she said. “We have not been flooded with calls about problems,” she said. “I think it’s been a good year.”