How is flour made is a question often asked by people as they are health conscious and interested in knowing about the origins of the product that they use on a daily basis. Flour is an everyday substance used in most homes around the country to make breads and other baked products. It is actually finely ground powder of a variety of grains though it is the flour made of wheat that is most commonly used in homes. Flour is used as one of the ingredients in many food items while it is also used solely to make breads and biscuits. There are many different varieties of flour being sold in the market these days besides the most common type that is wheat flour.
How is flour made – what is the process
Milling is the process carried out to obtain flour of wheat
The powdery substance flour results through a pulverizing process called milling. It is the dry grain that is used to make flour. While wheat is the most common grain that is used to make flour, oats, corn, barley, and even rice is used to make flour. It is not just the grain that is used to make flour that matters as the flour is also dependent upon the part of the grain that is retained in the powder that is finally produced. The grains of wheat, also known as kernels, are mainly made up of endosperm. This is the food storage part of the grain that is starchy in nature and makes up nearly 85% of the grain. However, there are several other parts of these grains. One of the outer layers is called bran while another outer layer that contains the embryo plant is called the oily germ. Oily germ makes up around 2% of the grain while bran constitutes 13% of the grain. All these parts of the kernel are crushed into a fine powder when whole wheat flour is required. In general though, white wheat flour that you see in stores is made by pulverizing the endosperm of the grains of wheat.
Manufacturing process of flour
Milling is the process of making flour from wheat grains. It consists of several stages that are described below.
Cleaning of the grains
Metal detectors, magnets, and other machines are used to remove metallic objects, stones, and other foreign materials from the wheat grains before they are milled. Other grains like barley, oats, and other plant materials also gets removed from wheat grains during this process. Cleaning of the wheat grains involves air currents that are used to clean off all the chaff and dust from the kernels.
Conditioning
After cleaning, conditioning of grain is done with water so as to soften the outer layer of the grain called bran. This allows for easier removal of the endosperm of the grain during the milling process.
Gristing
Gristing is a process in the manufacture of flour that allows for blending of different kinds of wheat. Sometimes, companies add wheat gluten at this stage to increase the percentage of protein in the flour that is produced.
Milling of wheat
This is the process of actual pulverization of the wheat kernels. Rolling, breaking, and sifting of wheat grains is resorted to during milling to obtain the powdery substance called flour.
Rotating rolls separate endosperm from the outer layers
Kernels of wheat are made to pass through rotating fluted rolls in such a manner that they are not crushed but forced to open up. This allows for separation of the inner white portion of these kernels from the outer layers. Different fragments of the kernels are separated by employing different types of sieves. These sieves are arranged at different places in a complex setting. The white inner endosperm of the grains is finally collected and made to go through rolls to be converted into white powdery substance called flour.
Sometimes, coarser bran attached with endosperm needs to be separated by making it go through a second round of break rolls. The process can be repeated several times until bran and wheat germ are totally separated. Whitest of flours is obtained with the first round of milling with wheat becoming browner as the percentage of bran particles increases in the flour.
Images Courtesy:
- Wheat by John Poyser (CC BY-SA 2.0)
- Flour by Margaret Hoogstrate (CC BY 3.0)
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