“Before CA. 150 years, a Hungarian miller ground the wheat between two steel cylinders and this led to the emergence of the current diagram technique. Flours which were both much more in amount and delivered more qualified and delicious dough were obtained from the wheat grains ground with steel cylinders succeeding gradually.”
Before many years, an action was filed claiming that the flour produced was defective, and the judge came for viewing. The judge climbing up the mill stairs breathlessly asked being unable to hide his surprise, “Are so many machines used only for producing flour?”
The reason for utilizing so many machines in flour production is due to the structural properties of the wheat grain being a seed that was created for producing its generation, rather than being ground and pulverized.
The wheat germ present at the lower, pointed end of the grain is the heart that brings the new plant into existing. Until the root ends sprouted from this part are started to feed by itself, the endosperm cells being the feeding source constitutes 4/5 of the grain. These cells are packed in an excellent, six-layer sheath called as bran.
Before CA. 150 years, a Hungarian miller ground the wheat between two steel cylinders and this led to the emergence of the current diagram technique. Flours which were both much more in amount and delivered more qualified and delicious dough were obtained from the wheat grains ground with steel cylinders succeeding gradually.
Along with the Industrial Revolution, the mills present in each village were converted into steel cylindered flour factories. And this led to a multiplied increase in flour production capacity and an intense competition. In the transition from the stone milling to steel cylindered factories, the ones who perceived the essence of the milling skill could survive.
Past masters, who could not visually see the differences in a very fine product such as flour, but comprehended the essence of the process, has brought the diagram technique to its current condition step by step through their fingertip feelings and observing the alterations in the dough pieces made of the obtained flour.
Today, the electron microscopes which multiply the invisible cell textures by one million times proved that how much the past master were precise.
Below, the view of a point at the edge of a wheat grain which was obtained with electron microscope shows the cellular texture of the wheat.
Endosperm cells consist of starch granules wrapped with proteins within a membrane (cell wall) comprising of lipids. If we draw a parallel between the interior structure of a cell and a masonry wall, starch granules resemble stones and proteins resemble the mortar wrapping the stones.
For the flour poured out the ground wheat grains, the more the parts maintaining their cellular integrity without damage to the cell membrane, the higher the quality of the dough made of such flour. Disintegration of cell wall causes to a too rapid water and enzyme penetration and a slack and sticky dough.
Among all other grinding tools, the reason for preferring the roller table consisting of two steel cylinders is that it enables grinding process with minimum cell wall damage.
In grinding with rollers, the in-cell locations and properties of the grains had led to the formation of diagram structure. With the aim of better explanation, when we draw a cross-sectional view of a wheat grain schematically and by colouring, an image resembling a smiling face obtained as shown below.
In order to understand where and how these cells are poured out as flour during grinding, let’s see a typical mill diagram developed step by step by the past masters who has turned milling into a professional culture since 150 years.
Two circles in this figure represent the roller bench and the rectangle represents the sieve where the ground materials are sifted. And the sign B1 shows that the passage consisting of a roller and sieve is the First Crushing passage where the wheat grains are crushed for the first time. The letter B indicates the crushing passages with groove threaded steel cylinder (roller ball) and the letter C indicates the lisso passages with flat surface balls.
The materials crushed in the rollers pass to the sieves. On the sieve, they are sifted with the sieve strainers having suitable sized pores. Sifted parts are separated according to their sizes. Crushed grains are the ones being larger than 1mm and having endosperm residues inside. The endosperm cell pellets being around a half millimeter and stuck to each form semolina. Among them, the ones being one-tenth of a millimeter, i.e. having the thickness of a strand, constitute flours. The flours collected in each passage are gathered in a one channel and delivers the end product. Separated other parts are sent to suitable passages via pipes so as to be further ground.
We stated previously that the main formation aim of the wheat is not to be ground; rather it is a seed that is created to continue its own generation. When we look at the wheat section shown above, we see that the crust (bran) which wraps the seed like a package and consists of seven layers, is recessed by twisting inwards the middle part of the grain. This recession disables the stripping and disintegration of the crust. It was selected to separate the endosperm from the crust by crushing and sifting the grain. On the roller benches, diagram technique providing grinding via rollers was emerged as they perform this process in the most successful manner. While passing through two balls, the crust disintegrated less and the endosperm in the interior part is crumbled. In sifting, semolina and flour are separated from each other easily in this way.
WELL, WHY THE FLOUR İS WANTED TO BE CLEAN OF THE CRUST?
Dough products such as bread especially, and biscuits, shredded pastry, past, etc. have been transformed into industrial products with many sorts and large capacities. In mass productions, it is a must that the dough is controllable. Protease enzymes contained in the crust and diluting the proteins prevent keeping the dough under control.
Considering the points explained above, let’s see where the cell groups shown in the section are transformed into flour by collocating the wheat grain section resembling a smiling face and the diagram.
It is seen that the large and round cells, which are richer in starch and low in protein, shown in red colour in the section are turned into flour in B1-B2-Div-C1 and C2 passages again shown in red colour in the diagram. Ash ratio (the extent of being cleaned of crust) of these passages is 0.35 – 0.45% and their protein content is around %9. As to define in terms of quality, these passages are called as first quality passages.
Again, it is seen that the cells shown in blue colour in the section and the diagram are poured out from B3-C3-C4 passages. Their ash ratio is 0.45 – 0.65% and their protein content is around 11%. These passages are called as second quality.
It is also seen that the flours consisting of the cell groups which are shown in green colour and close to the crust are poured out from third quality passages. Their ash ratio is 0.65 – 1.20% and their protein content is around 13%.
The quantitative values given here are the general averages. The aim is to explain with more tangible values when telling where the cell groups are turned into flour according to their properties and locations in the section.
In fact, each wheat type has a different value. Wheat has been domesticated since thousands of years and it has many varieties and types. Each type has specific properties. Producing stable flour with the raw material obtained in this way and being quite variable is based on milling knowledge and skills.