When sourcing whole wheat flour, the protein content is the most critical indicator of performance; for bread making, look for 12% to 14% protein, while pastry applications require lower levels. You must also verify the extraction rate, as true whole wheat should contain 100% of the wheat kernel (bran, germ, and endosperm). Additionally, check the granularity (mesh size)—finer grinds are better for soft textures, while coarse grinds provide a rustic feel. Ensure the moisture content is below 14% to prevent mold growth and enzymatic activity during transit.