A middlings purifier is a device used in the production of

flour Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many culture ...

to remove the

husk Husk (or hull) in botany is the outer shell or coating of a seed. In the United States, the term husk often refers to the leafy outer covering of an ear of maize (corn) as it grows on the plant. Literally, a husk or hull includes the protective ...

s from the kernels of

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

. It was developed in

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

by Edmund LaCroix, a French inventor hired by

Cadwallader C. Washburn Cadwallader Colden Washburn (April 22, 1818May 14, 1882) was an American businessman, politician, and soldier who founded a mill that later became General Mills. A member of the Washburn family of Maine, he was a U.S. Congressman and governor o ...

and George Christian of the

Washburn "A" Mill Mill City Museum is a Minnesota Historical Society museum in Minneapolis. It opened in 2003 built in the ruins of the Washburn "A" Mill next to Mill Ruins Park on the banks of the Mississippi River. The museum focuses on the founding and growth ...

. It was developed to complement the emerging roller mill technique of the late 19th century, which used corrugated metal rollers instead of abrasive grindstones to grind wheat into flour. The middlings purifier was used to separate the

bran Bran, also known as miller's bran, is the hard outer layers of Cereal, cereal grain. It consists of the combined aleurone and pericarp. Corn (maize) bran also includes the pedicel (tip cap). Along with cereal germ, germ, it is an integral pa ...

from the usable part of the flour. The machine developed by LaCroix passed the partially ground middlings over a screen, and a stream of air blew away the particles of bran. This process was used because winter wheat, sown in the fall and harvested early the next summer was not feasible to grow in Minnesota. Spring wheat was sown in the spring and harvested in late summer. 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. It was also difficult to mix the gluten and the starch completely. After Washburn's company developed the roller-milling technique with the use of a middlings purifier, they tried to monopolize the method, but the

Pillsbury Company The Pillsbury Company is a Minneapolis, Minnesota-based company that was one of the world's largest producers of cereal, grain and other foodstuffs until it was bought by General Mills in 2001. General Mills brands consist of Annie's, Betty Croc ...

and other competitors were able to duplicate the process thanks to employees who left Washburn and passed along

trade secrets Trade secrets are a type of intellectual property that includes formulas, practices, processes, designs, instruments, patterns, or compilations of information that have inherent economic value because they are not generally known or readily as ...

. The development of the middling purifier may have been based on the invention of the purifier by Ignaz Paul, an Austrian Miller and inventor (1778 - 1842) early in the 19th century.{{cite book , url=https://archive.org/details/bub_gb_6jRDAAAAIAAJ , title=Report on Vienna bread , author=Eben Norton Horsford , page
31
��32 , publisher=Washington: Government Printing Office , year=1875 , accessdate=2012-11-02 Washburn later teamed up with John Crosby to form the Washburn-Crosby Company, which eventually became

General Mills General Mills, Inc., is an American multinational manufacturer and marketer of branded processed consumer foods sold through retail stores. Founded on the banks of the Mississippi River at Saint Anthony Falls in Minneapolis, the company orig ...

References

History of Minnesota Flour Food technology