In the 1870s and 1880s, important changes took place inside several small flour mills in southeastern Minnesota. Those changes laid the groundwork for a technological revolution that made Minnesota's milling industry the largest in the world.
The changes grew out of a desire by millers to improve the quality of their flour. Most Minnesota farmers raised hard spring wheat, which had a reputation for producing speckled flour. Drawing on European technology, Minnesota millers developed a method of refining their flour by sending it through a purifier that removes the specks, or middlings, and by grinding the flour several times. Called the New Process, this method produced a whiter, purer flour that was soon in demand by consumers.
One of the first to experiment with this new technique was Northfield miller Jesse Ames, who used a purifier as early as 1865. Within a few years, purifiers were found at the Archibald mill in Dundas, the Mowbray mill in Stockton, the Gardner mill in Hastings, and the Faribault mill.
As the changes swept the milling industry in the 1870s, millers concluded that the traditional millstone, which required frequent redressing, was no longer efficient. They turned instead to rollers, already used in some parts of Europe. One of the earliest American attempts at roller milling occurred in 1872-73 at the Mowbray mill, where four-foot marble rollers were installed. Soon most Minnesota millers had replaced their old millstones, opting for more efficient porcelain-covered or iron rollers.