Aging and Bleaching

Freshly milled flour is not good for bread making. The gluten is somewhat weak and inelastic, and the color may be yellowish. When the flour is aged for several months, the oxygen in the air matures the proteins so they are stronger and more elastic, and it bleaches the color slightly.

Aging flour is costly and haphazard, however, so millers may add small quantities of certain chemicals to accomplish the same results quickly. Bromates, specifically potassium bromate, added to bread flours mature the gluten but do not bleach the flour a great deal. Bromate use is decreasing because of concerns about its safety, and it is not used at all in Canada and Europe. Other additives, such as ascorbic acid (vitamin C), are used instead.