Grain Handling

Grain Production

Historic varieties dating to 1808 (and likely earlier) were acquired through the National Small Grains Collection (located in Aberdeen, Idaho, and formerly in Beltsville, Maryland). These are grown with contemporary cultivars. Plant characteristics of the historic varieties and contemporary cultivars are compared with recorded plant descriptions; the identity of the various varieties is confirmed. Yearly, the SWQL grows 200 to 300 cultivars/varieties in forty-square-foot plots.

Grain Cleaning and Sizing

Prior to 1985, most of the shriveled grain was removed mechanically utilizing a modified Carter-Day dockage tester or an air-flow scourer. However, some shriveled grain could have been present in the remaining sample. In 1985, the Carter-Day was further modified to remove shriveled kernels by air aspiration. The ability to remove shrunken grain was greatly enhanced, but the process was time consuming.

In 1989, a large air-aspirator was fabricated by the SWQL that reduced cleaning time significantly and removed shriveled kernels. In 2002, the SWQL began to re-evaluate cultivars that were tested prior to 1989 and to update the milling information if needed. That effort was mostly completed in the summer of 2006.

Every cultivar designated for Allis milling is mechanically sized into three or four fractions on a SWQL-modified Carter-Day Dockage Tester and then aspirated. A maximum of 2500 grams can be aspirated at one time. Air flow is electronically adjustable and the lower density shriveled grain within each sized fraction is removed. Visual inspection through a lighted magnifier is used to ascertain that only sound grain remains. Once aspiration of the wheat has been completed, the cleaned sized fractions are blended. Test weight, 1000-kernel weight and moisture are determined prior to milling.

Weather and Environment

Weather damaged cultivars that produce diminished milling quality can be difficult to identify if known standards are not incorporated within the field trial. In the northern soft wheat region, wet weather at or near harvest time occurred most years from 1990 to 2000 and again in 2003. Some cultivars prominent during that decade produced milling quality data unreflective of their true genetic potential. After a specific cultivar is identified that produced "invalid" milling data, that milling information is replaced with the updated analysis. A cultivar's' revised milling score could increase by as much as two standard deviations.

An "off color" flour can appear in wheats which are genetically "white" when there is an excessive quantity of wet weather at harvest time. A yellowish flour color sometimes occurs in cultivars that are normally white when the environment "produces" a coarser granulating flour than normal.

Wet weather at harvest time will lower test weights and grain density, and can greatly increase the softness of the kernel so that the flour produces larger cookie spread, although milling-yield potential is not affected. Throughput at the 1st-break rolls is diminished with weathered wheat. However, since the wheat is softer, break-flour yield increases and less middling stock is passed to the reduction rolls. That would result in reduced energy required to power the rolls with less wear on the roll surface. More throughput could possibly be realized with softer-weathered wheat versus coarser type wheat if a double 1st-break system were employed.

Excessively wet weather at harvest time can damage wheat for milling quality. Sprouted wheat (after aspiration) can possess higher test weights than unsprouted wheats. After aspiration to remove shriveled grain, a sprouted wheat may have a test weight in excess of 60# / bushel compared to weathered, unsprouted, non-shriveled wheat with 57# / bushel test weight. Alpha-amylase activity may be present despite a lack of visual evidence of sprouting.

Moderate infection from leaf diseases apparently does not affect milling properties once damaged (shriveled) kernels have been removed; however, baking quality of sugar snap cookies may be affected.