A middlings purifier is a device used in the production of flour to remove the husks from the kernels of wheat.
The machine developed by LaCroix passed the partially ground middlings over a screen, and a stream of air blew away the particles of bran.
[2] This process was used because winter wheat, sown in the fall and harvested early the next summer was not feasible to grow in Minnesota.
This could be grown by Minnesota farmers, but the conventional techniques of grinding grain between millstones ended up producing a darker flour than consumers desired.
[3] Washburn later teamed up with John Crosby to form the Washburn-Crosby Company, which eventually became General Mills.