If you are looking for more information about wheat flour, you’ve come to the right place!
In this article I will discuss:
Let’s dig in!
1. What is the definition of flour
Flour is basically any starchy part of a plant that is ground into a fine powder.
These powders are used in cooking, especially baking.
Flour from wheat grains is the most common flour.
Aside from the different sources of flour, you also get different types of flours. Examples include all-purpose flour, bread flour, pastry flour and, of course, cake flour.
For people that have specific dietary requirements, like people that are gluten-intolerant, you get flours that are not made of wheat, barley, rye or triticale.
These four cereals are the most common ones that have the protein called gluten, in them.
2. The history of wheat flour
Flour has been around for millennia.
In the early times people used stones to grind grains into flour. There were different variants of this system with the hand-operated mortar and pestle, and saddle-quern being some of the more common ones used.
The millstone was later developed and could be driven by animal power.
Waterwheels were later used to power mills by the ancient Romans.
And by the 12th century windmills were used to power millstones in Europe.
In 1632 the first mill in the American colonies, powered by wind, appeared in Boston.
Oliver Evans built the first fully automated mill in 1784 near Philadelphia.
After this, during the 19th century, many improvements were made.
The first middlings purifier was introduced by Edmund La Croix in 1865.
This device separated the husks from the kernels. It does so by blowing air through a vibrating screen.
In 1878, in Minneapolis, the first mill using metal rollers, was used.
3. What is wheat flour made from
The answer to this question may seem obvious: wheat flour is made from wheat.
Right?
This is true, in essence.
Here is the catch, though: you get different types of wheat flour.
And what distinguishes different types of wheat flour is the parts of the wheat kernel it’s made from.
To properly understand this I have to explain the 4 different parts of the wheat grain.
The outer hard protective layer is called the husk.
The inner three parts together form the kernel.
The kernel is the part that gets used and is in turn made up of the outer harder layer called the bran, and two inner parts called the endosperm and the germ.
The endosperm serves as the food supply to the germ for the first root and leaf development, until the young plant can start taking up its own water and nutrients with this newly formed root system.
White wheat flour is made from only the endosperm.
On the other hand, whole-wheat flour is made from all 3 parts: the bran, the endosperm and the germ.
4. How do farmers grow wheat
Wheat is one of the most cultivated crops in the world.
In the 2020/2021 season 772.64 million metric tons of wheat was produced worldwide.
Farmers sow wheat in autumn using a tractor and a seeder.
A tractor is the machine that pulls implements used in agriculture, like seeders, and the seeder is the implement that physically plants the wheat seeds in the ground.
Depending on the soil nutrient levels, fertilizer is also applied to supply the growing wheat plants with the required nutrition to grow.
These wheat fields, or paddocks, can either be irrigated or dryland.
Irrigated fields are manually irrigated using irrigation system like center pivots, while dyland wheat field rely on rainfall for all its moisture requirements.
Irrigated wheat field have higher grain yields because they can be given more water and nutrients for growth.
5. How does wheat get harvested
Once wheat is fully grown out and has set seed, and those seeds have dried out to acceptable moisture levels, it can be harvested.
Farmers use combines with headers to harvest wheat grains.
These machines cut off the grain heads that contain all the grain seeds and separate the grains from the rest of the plant.
The grain is kept in the storage compartment of the harvester until it gets full, wherafter it gets loaded into a transport vehicle to be transported to the storage site.
The rest of the plant parts that was harvested and separated from the grain is spread back onto the field behind the harvester.
These harvesters are also capable of dumping the harvested grain straight into the transport vehicles while harvesting.
When done this way, the transport vehicle drives alongside the harvester while being filled with grain until full.
6. Storage of wheat grain
After the wheat has been harvested, it gets stored until it gets sent off to processing facilities.
This storage could be either on the farm itself if the infrastructure is there, or in centrally located sites owned by agricultural companies or the government.
Wheat, as with any other grain, can be stored in different ways.
The two most common ways is in either grain silos or silo bags.
Fixed grain silos are big cylindrical units built either from metal or concrete.
7. Processing of wheat grain into flour
If the wheat is destined to be made into flour, it is sent from the silos to flour mills.
A flour mill is the place where wheat, as well as other grains, gets ground to produce the finer powdered product that resembles flour as we know it.
When the wheat gets to the flour mill, it is graded.
Wheat graders look at several factors of the wheat to assign a grade, with the most important factor being protein content. They also determine the ash and moisture content.
Thereafter the different grades of wheat gets stored in different silos at the mill until it is ground into flour.
There are three basic steps in the processing of wheat grains into ground flour.
7.1 Purifying the wheat grain
The first step of the milling process is to get rid of larger objects like rocks and sticks.
This is the job of a device called a seperator.
It is basically a set of metal screens over which the wheat is moved where the wheat grains and smaller matter falls through. It is similar to a large sieve.
Just after the separator, the aspirator sucks out lighter materials like leaves. The aspirator is similar to a giant vacuum cleaner.
Another process is where the wheat grain is run through a machine called a spiral seed separator.
This machine spins the wheat grains around in a large cylinder where the oval shaped wheat seeds moves more towards the center of the cylinder while round seeds from other plants moves to the sides.
This way other undesired seeds get separated from the wheat grains.
Some other methods to purify the grain can include magnets to remove metallic objects like pieces of wire, sorting machines using color to separate materials that is not the same color as wheat, and scrapers that removes dirt and mud.
7.2 Preparing the wheat grain for grinding
The grain is washed first.
After it is washed it is put into a large centrifuge. This machine spins the grain at high speed to separate the water from the grain.
Then the wheat is conditioned.
This is where the moisture in the grain gets manipulated to the optimal level where the bran can be removed during the grinding process.
This can be done by soaking the grain in warm or cold water or exposing it to steam. The process chosen depends on what the desired moisture content is, and that could also mean to increase moisture content, not just to decrease it.
In the case where wheat grain gets over moisturised, large vacuum dryers can dry it out again.
7.3 Grinding the wheat grain
This step is where the wheat grain finally gets ground to the fine flour we know.
The wheat grain goes through two large metal rollers moving at different speeds. This process is called break rolling and is where the grain gets crushed to expose the endosperm and germ.
These breaker rollers also have grooves which help to separate the bran from the endosperm.
You now have raw flour.
This flour is passed through sieves and gets separated into three main categories according to particle size.
The finest of these is almost the same texture as course flour and is called farina or middlings.
The larger size category is called semolina and contains the larger pieces of the endosperm.
The largest of the three categories contains the bran with pieces of the endosperm still stuck to it.
The larger two categories goes through more breaker rollers to get more middlings produced, with up to 5 sets of breaker rollers needed to produce the necessary amount of middlings.
All the middlings then pass through a middling separator to remove the pieces of bran that is still mixed in with the middlings.
Finally, these refined middlings are then passed through another set of smooth metal rollers that grinds it down to the desired coarseness.
8. Refining wheat flour into the final product
After the milling process, oxidising agents and small amounts of bleaching agents is added to the flour to help prevent spoilage.
When required by law, vitamins and minerals are added to produce enriched flour.
In the case of self rising flour, salt and leavening agents are added.
Flour is then matured for up to two months.
The final product is bagged and shipped of to suppliers.
9. The uses of wheat flour
The most common use for wheat flour is as an ingredient in baking where it is responsible for giving baked goods structure.
There are proteins in wheat flour that, when mixed with water, interacts with each other to form a substance called gluten.
Gluten is elastic and it’s main function is to provide structure and support to baked goods.
It does so by containing and encapsulating the gasses that form when dough rises.
The strength and rigidity of dough depends on the protein content of flour.
The higher the protein content, the higher the gluten content in dough. In turn, the higher the gluten content, the more structure.
When baking bread, for example, you want flour with a higher protein content. That is also the case for when baking with yeast or when making cut-out cookies.
On the other hand, when you want a more tender crumb like muffins, quick breads or cookies, use flour with a lower protein content.
Talk of Tomatoes wrote a great article delving deeper into the protein content of flour, you can read it here.
10. Different grades of wheat flour
The grade of wheat flour depends on its contents.
The three main components that determines the grade is the protein content, the ash content and the moisture content.
The grade of flour determines what the flour is most suitable for when it comes to cooking and baking.
10.1 Protein content
I have touched on protein content earlier, but just to recap.
Protein content is responsible for the gluten level, which in turn affects the level of structure in your baked goods.
The more protein there is, the more structure and vice versa.
The level of protein can be determined with methods like the Kjeldahl method and near infrared spectroscopy (NIS).
Also note that the level of protein is one thing, but the quality is something else.
10.2 Ash content
Water, fibers, fat, protein and starch make up what is called the organic component of wheat.
There is, however, also a smaller inorganic component that make up about 1% of wheat flour.
This is called the ash content and includes elements like iron and zinc.
Most of these ash components are contained in the bran part of the wheat kernel.
Therefore, white flour, that is produced from only the endosperm, will have almost none of these whereas whole wheat flour will have higher levels of ash.
To measure the level of ash, the flour sample is combusted. The ash left is measured and that is where the ash level comes from.
10.3 Moisture content
As with all living things, wheat and wheat flour contains water.
Although wheat flour may seem dried out, there is normally between 13.5% and 14% of water present.
Water level is important because it affects microbial activity. If the moisture levels are too high, mould and bacteria will spoil the flour quicker.
A moisture level of 14% is the maximum acceptable moisture level.
This is also the reason farmers have to delay the harvesting process and wait for the wheat kernel in the field to dry off to acceptable moisture levels.
Moisture levels also influences the milling process. If the wheat grain is too wet, the ground up wheat flour would be too wet and clogged.
On the other hand, if it is too dry, the mill will struggle more to crush the grains.
Moisture levels are determined using methods like near infrared spectroscopy (NIS).
If you are interested in more detail when it comes to wheat flour grade and quality, Food Crumbles wrote a great article that you can read here.
11. Is wheat flour healthy
When you look at the nutritional value of wheat flour, you have to take into account what type of flour it is.
White flour is made using only a certain part of the wheat kernel with the bran and germ being removed after milling.
The bran and germ are the parts that contain a lot of the vitamins and minerals.
Whole wheat flour, on the other hand, contains these parts as well.
Therefore, when comparing different wheat flours, whole wheat flour is definitely the healthier option being a great source of vitamins, minerals, protein and fiber.
Wheat flour, however, contains gluten.
Therefore it’s not suitable for people with celiac disease or gluten sensitivity.
12. Average nutritional values of wheat flour
According to the United States Department of Agriculture, half a cup (60g/2.1 oz) of 100% whole wheat flour contains the following:
- Protein: 8 grams
- Fat: 0 grams
- Carbohydrates: 42 grams
- Potassium: 5% of the DV
- Iron: 11% of the DV
- Fiber: 8 grams
- Calories: 200
Final thoughts
Wheat flour is the most widely used flour in the world and I doubt that will change anytime soon.
It gets used in a ton of different baked goods and dishes.
Next time you drive by a wheat field, you will appreciate the journey all those grains take to end up in those delicious baked goodies back home!