What is milling?
Milling is the process of grinding grains to make them usable for consumption as flour or baking products. Wheat grains are rolled, ground and sifted into the separate parts that make up a grain of wheat-the bran, germ and endosperm.
Preparing wheat for the mill
Wheat that is delivered to a mill is weighed and moisture and protein levels are determined. Food safety checks are in place to test for non wheat materials, insects, fusarium damaged wheat or other types of grain. Once the quality control tests are complete the grain is ready to be milled.
There are different varieties of wheat with different levels of protein that are used to make different products such as bread, cakes, noodles and more.
Milling
In preparation for milling, the wheat grains are tempered and rest in temper bins to condition for up to 24 hours. Tempering is the process of adding water to soften the bran layer (outer layer) of the wheat.
The wheat is milled using a roller mill that cracks or breaks the grain by passing it between closely spaced metal rollers. The crushed grains pass through a series of rollers until finely crushed. The crushed grains are separated by sifting which removes the bran from the flour and by air current separation to make different kinds of flour.
Conditioning and Bleaching
Once the milling process is complete, some flours are conditioned to enrich and fortify, enhance appearance and increase functionality. Refined white wheat flour must be enriched to replace the loss of vitamins and minerals that occurs during processing. Powdered vitamins and minerals, such as folic acid, iron, riboflavin and thiamine are added to the flour.
As flour ages it naturally becomes lighter in colour due to the exposure to oxygen but this process can take several months. To speed up the process, millers add conditioners (called bleaching) that create a smooth texture and improve the quality of the flour.
Source: Whataboutwheat, goodineverygrain, lifessimpleingredient