Specification Limitations for Hard and Soft Wheat Flour

Suppose the protein content in a load of soft wheat flour is initially measured as 8.15% and later the same load is measured as 7.95% protein. Is the difference between the two measurements real? How precisely can protein in soft wheat be measured? This white paper estimates specification limitations of several measurements used for both hard and soft wheat flours. Guidelines are provided for determining whether the difference between two measurements is within the range of measurement uncertainty. For example, how large must the difference be to suggest two lots are not actually the same flour or that somehow the flour has changed in the time between the two measurements? Data provided by the check sample programs of the AACC International Cincinnati and Pioneer Sections are used to estimate specification limitations for moisture, protein, ash, and falling number in hard and soft wheat flours, as well as pH in soft wheat flour.