Wheat cleaning practices of U.S. commercial elevators - report derived from survey of grain elevator managers by National Grain and Feed Association - U.S. Dept. of Agriculture, Economic Research Service report

Situation and Outlook Report: Wheat, Nov, 1991 by Brian Just, Kristi McComas, Mark Ash, Bengt Hyberg

Stages of Cleaning

Wheat can be cleaned more than once. There is little additional breakage with each handling (unlike corn) but smaller, less dense kernels are lost by cleaning. Most country elevators that cleaned wheat did it promptly upon receipt from the farmer. However, there were some regional differences. Elevators cleaned proportionately twice as much winter wheat during storage or turning than spring wheat. Cleaning during storage requires an additional elevation, thus imposing more costs on a facility. Country elevators cleaned more grain upon receipt, while terminal and export elevators cleaned relatively more at loadout. Most elevators from the survey are not currently equipped to reduce nongrain material to the very low levels (0.01 percent or less) desired by flour millers. According to the MNF survey, most millers said it costs no more to clean wheat with 1 percent dockage than 0.1 percent dockage. Consequently, the responding millers cleaned all of their wheat prior to milling, regardless of its previous history. Very few of the responding flour millers offered premiums for low-dockage wheat or had maximum limits on the amount of dockage allowed. Millers that did offer premiums or had higher than average discounts for foreign material had higher costs of cleaning than other millers. The average variable cleaning cost from the MNF survey was 4.4 cents per bushel. This cost was based on a much lower final nongrain material content than the elevators with cleaners reported. Nearly all the millers responding combined grain cleanings with the milling byproducts, which are sold for feed. A regular market for milling byproducts is already well-developed in the United States.

Geography of Cleaning Wheat

States in which hard red spring wheat is harvested cleaned more than other states. In the year covered by the survey, 97 percent of the elevators in North and South Dakota cleaned spring wheat. In South Dakota, half of the elevators cleaned all the grain they handled. In North Dakota, half of the elevators cleaned at least 75 percent of the wheat handled. About half of the Minnesota elevators cleaned at least 50 percent of the wheat handled. By contrast, only 33 percent of elevators cleaned winter wheat in Texas and Oklahoma. And elevators in the white wheat areas of the Pacific Northwest cleaned minimally. Larger elevators (export or terminal) typically cleaned a smaller percentage of their total grain volume.

Costs To Clean

The operating cost of a grain cleaner depends on the efficiency of the model and its throughput capacity. The amount of dockage in incoming wheat (or the desired level of cleanliness) then determines the hours of use. The conjunction of these factors determines the variable costs, which include electricity, labor, and maintenance. The elevators' variable cost of cleaning wheat increased with the amount of dockage removed (figure A-7). The weighted average of the cost estimates provided by elevators was about 4.9 cents per bushel for a 1 percent reduction in dockage and 7.3 cents for a reduction greater than 2 percent. When elevators clean, they remove, on average, 1.7-2.0 percent of the volume as dockage. According to the survey, elevators' variable cleaning cost also varies with the volume handled (figure A-8). Elevators that clean a high proportion of their grain had a lower per-unit cleaning cost, and vice-versa.