SMUT on Pacific Coast Wheat Can Profitably Be Removed by Washing

Wheat has been afflicted with stinking smut since the days of the Old Testament. Each year a surprising percentage of the wheat crop of our country is infected with this black, ill-smelling dust called smut.  In the heads of growing wheat either clean normal wheat kernels or brownish-black smut balls are found; wheat kernels and smut balls seldom grow in the same head. The smut appears in threshed wheat as a mixture of whole smut balls and smut dust with the wheat.  Smut dust is made up of millions of minute spores from the smut balls that are crushed in the thresher. Smutty wheat looks and smells very foul but the smut and its odor can be removed effectively by machinery designed for that purpose.

In the Pacific Northwest, where seed treatment as a smut-control practice is not entirely effective because of the dry-land method of farming, smut in wheat has reached the point where about half the wheat bought from the farmers is graded as "smutty.” The presence of smut in wheat presents a serious handicap to- efficient marketing, as all smutty wheat must be passed through the smut-removing machines.

For many years the only method of removing smut from wheat for export and the trade was by a dry scouring process. Pacific coast wheat is usually so dry and brittle that dry scouring damages the wheat by cracking many kernels. Pieces of finely cracked wheat mingle with the smut-and are lost. The resulting loss in weight due to dry scouring often exceeds the percentage allowed by the State grain inspection department as "smut dockage.” Scoured wheat, because of the injury to the germs, is unsuitable for seed.

Washers for removing smut from wheat have been in use in flour mills for many years, but until recently it was assumed that these washers could not be used for removing smut from wheat for commerce, as it was thought that washed wheat could not be safely stored without drying.

The Federal grain investigations office of the Pacific coast conducted a study of a wheat-washing process at the Portland, Oreg., municipal grain elevator on more than 5,000 tons of smutty wheat which was washed for export to determine the effect on the weight and grading factors. Washing was found to be effective and satisfactory in removing smut, the test weight of wheat was materially reduced immediately after washing, but the wheat tends to regain most of its original test weight, as the moisture penetrates the kernels.

The wheat gained weight during washing. There was over 2.5 per cent more weight of merchantable wheat after washing than before.  The germination quality of the wheat was only slightly reduced. At present the washing method of removing smut from Pacific coast wheat is rapidly coming into use in preference to the dry-scouring methods.