Samples of some advanced nurseries are milled on a Buhler MLU-202 pneumatic laboratory mill (Figure 1). The samples are tempered to a predetermined moisture content ranging from 14.0% to 16.0%, depending on the hardness and known flour-bolting properties. The harder wheats require more water. Thus, the grain is conditioned so that the most rapid and complete separation of endosperm can be made. The temper solution contains a wetting agent (0.1% Aerosol OT) to hasten moisture penetration. The wheat is allowed to temper for 16-24 hours before milling to permit uniform distribution of the moisture. An additional 0.5% water is added 15-20 minutes prior to milling. The first and second break and first and second reduction streams predict long patent flour yield. All six flour streams are then combined to make a straight-grade white flour by sifting on a 120 stainless steel wire screen and thoroughly blending.
Flour Yield (FYELD): The percentage by weight of the total products recovered as straight-grade white flour.
Break Flour Yield (BFYELD): The percentage by weight of the total products recovered as flour off the break rolls.
Milling Time: The time required in minutes to mill a 2-kg sample with the Buhler experimental mill and obtain a normal separation of bran, shorts, and flour. Time is dependent on adjustments made by an experienced miller after visually observing the milling properties.
Milling Score (MSCOR): Calculated as follows:
MSCOR = 100 – [(80 – flour yield) + 50 (flour ash – .30)
+ 0.48 (milling time – 12.5) + 0.5 (65 – percent long patent)
+ 0.5 (16 – first tempering moisture)]