Even though this machinery has improved greatly over the centuries, modern cleaning and milling actually takes longer than ancient forms of flour making. Stone mills were in use for centuries and flour was principally a food for the wealthy. However, in the late 1800s, huge improvements in industry and the creation of the roller mill made it possible for nearly everyone to integrate flour into their diet without trouble. Modern technology takes a bit longer to prepare the flour because it is more thorough in cleaning the kernels, creating even texture and enriching.
How does grain processing equipment clean the food?
During harvest, combines pick up more than just the kernels. While they are designed to remove as much inedible material as possible, harvesters still pick up straw, small bits of iron and pebbles. If allowed to remain in the flour, they can cause food contamination or cause health problems. They can also damage mills and other machines, so they must be removed as soon as they arrive at the facility. Sifters, magnetic separators, sorting machines and meshes are all used to remove this material before further preparation can begin. Some facilities also use aspirators or air pressure to clean off any fine straw or inedible material from the kernels.
What does grain processing equipment do to convert the kernels to flour?
After the material is sorted by size using a number of length and width graders, it is transported to the roller mills for grinding. The kernels are placed in the mill and a series of powerful rotating shafts crush each kernel. The shafts are placed just a millimeter or two apart, preventing any kernels from falling through untouched. The “first break” usually reduces the kernels to a mix of large bran pieces and rough flour. The bran is separated out and the rough flour is sent through the roller mills repeatedly until it is reduced to a fine silky texture. This can be enriched and packaged as white flour or the bran can be added back in to create whole wheat flour.
What is done to the flour before it is packaged?
Once the material is sifted out into its different products (white flour, whole wheat flour, bran, semolina, etc.), it is often enriched. This is usually only necessary for white flour and imparts much of the nutrition lost during preparation back into the flour. Enrichment returns iron, folic acid, niacin, thiamine, riboflavin and folic acid back into the product, though calcium may also be mixed back in. This improves the nutritional quality of the food and simulates the presence of the bran and germ.
Though we now take a little longer to produce prepared kernels for consumption, the added safety, flavor and nutrition is worth the extra effort.