As a matter of fact, the earliest archaeological evidence for wheat seeds crushed between simple millstones to make flour dates to 6000 BC. But humans have come a long way since then, because now they're using electric flour mills instead. Besides, flour now is made by grinding raw grains, roots, beans, nuts or seeds. Cereal flour, for instance, is the main ingredient of bread, which is a staple food for most cultures. It is worth noting that the higher the protein content the harder and stronger the flour, and the more it will produce crusty or chewy breads. The lower the protein the softer the flour, which is better for cakes, cookies, and pie crusts.