 Saint Anthony Falls , the only waterfall of its height on the Mississippi , played an important part in the development of Minneapolis . The power of the waterfall first fueled sawmills , but later it was tapped to serve flour mills . In 1870 , only a small number of flour mills were in the Minneapolis area , but by 1900 Minnesota mills were grinding 14 @.@ 1 % of the nation 's grain . Advances in transportation , milling technology , and water power combined to give Minneapolis a dominance in the milling industry . Spring wheat could be sown in the spring and harvested in late summer , but it posed special problems for milling . To get around these problems , Minneapolis millers made use of new technology . They invented the middlings purifier , a device that used jets of air to remove the husks from the flour early in the milling process . They also started using roller mills , as opposed to grindstones . A series of rollers gradually broke down the kernels and integrated the gluten with the starch . These improvements led to the production of " patent " flour , which commanded almost double the price of " bakers " or " clear " flour , which it replaced . Pillsbury and the Washburn @-@ Crosby Company ( a forerunner of General Mills ) became the leaders in the Minneapolis milling industry . This leadership in milling later declined as milling was no longer dependent on water power , but the dominance of the mills contributed greatly to the economy of Minneapolis and Minnesota , attracting people and money to the region . 
