The main cereals cultivated to obtain flour and semolina are:

● Wheat (soft and hard)
● Corn
● Rice
● Barley
● Sorghum
● Oats
● Rye

The difference between flour and semolina is very simple.
We can say that we are talking about flour when there is the milling of soft wheat, while we are talking about semolina when there is the milling of hard wheat. With the same processing method, therefore, two different products are obtained.
In Italy, soft wheat is mainly grown in the North, while hard wheat is more grown in the South, consequently in terms of cuisine, flour is more used in the north and semolina in the south.
The products obtained are visually a bit different, finer and light yellow the flour while the semolina is coarser and with a darker color. Even in cooking, the uses are different, usually the flour is in fact used for baked goods while the semolina for pasta.

Types of flour

It is called soft wheat flour (or flour) the product obtained from the milling and consequent sifting of soft wheat.
Soft wheat wholemeal flour means the product obtained directly from the milling of soft wheat.
Sifting is the process of gradual sieving of the milled grain to obtain flour of different fineness.
It means the process of separating the noble part of the grain from the bran using different mesh sieves. The sifting rate or milling yield is the quantity of flour obtained from the milling of one hundred kilograms of grain. In other words, it represents the percentage of kernel used for a particular flour.
The higher this index, the coarser the flour.
Depending on the sifting rate, and therefore on the refining of the kernel, and on the strength (W), soft wheat flours are distinguished into five types (quantity of bran and germ gradually increasing): “00”, “0”, “1”, “2” and wholemeal.
00 flour has undergone a sifting of 50%; 0 flour of 72%, type 1 flour of 80% and type 2 flour of 85%; wholemeal flour has only undergone a first milling phase, without further sifting, and has a sifting rate of 100%.

Types of semolina

It is called semolina of durum wheat (or semola rimacinata/Re-milled semola), the granular product obtained from the milling and consequent sifting of durum wheat.
It is called durum wheat semola (or semolato) the product obtained from the milling and consequent sifting of durum wheat, after the extraction of the semolina.
Durum wheat wholemeal semolina means the live granular product obtained directly from the milling of durum wheat.
Durum wheat semolina is the non-granular product obtained from the milling and consequent sifting of durum wheat.

Flour and semolina: properties

Remember that the products of the milling of DURUM wheat are semolina and semolato, those of SOFT wheat, flours.
The anatomical structure of the wheat kernel is similar to that of other cereals: embryo or germ (2-4% by weight), integuments or wrappers (about 8% with a protective function rich in cellulose fibers and mineral salts) from which the bran is obtained, starchy endosperm or mealy almond rich in proteins, lipids, soluble sugars, vitamins and mineral salts (87-89% approximately) from which flours and semolinas are obtained.

The soft wheat flours on the market are all obtained from the milling of different varieties of grains.
This technique allows the mills to correct and make the product characteristics stable during the natural variations that the grains have during the year. In fact, it should not be forgotten that there is only one annual harvest at the beginning of summer.
The quality of the flours is determined on the basis of their rheological properties, therefore on the basis of the resistance presented by the doughs to processing and therefore to the deformation forces.
The latter are also determined by the quality of the gluten contained in the flours: a protein complex that develops when the two proteins gliadin and glutenin come into contact with water. Based on these characteristics and some chemical parameters, their intended uses differ.

End uses of flour and semolina

● Durum wheat
In the case of durum wheat, almost all of the flours produced are intended for pasta
making. Durum wheat semolina is a high-protein flour that is typically used to make
pasta. It can also be used to make differs styles of bread, or couscous, and other
grain-based dishes.
● Soft wheat
Soft wheat flours are used for a plurality of products, from bread to pastries. The
strength of a flour (W) depends on the quantity and quality of gluten that it is in grado
di sviluppare and its consequent ability to absorb water. The quantity and the ratio of
the proteins that are contained in the wheat kernel, determine the quantity and
quality of the gluten that will be developed in the dough.
Therefore, it is possible to observe flours with the same protein content that, however,
develop gluten in different ways and therefore have different strengths because they absorb
different quantities of water.
The strength (W) indicates the water that the proteins can absorb without the dough losing
stability, and therefore guarantee an adequate leavening development. Through the bran I
can insert more water into the dough which, however, does not go to be part of the gluten
network, but remains precisely in the bran. At the same gluten network, a flour with more
bran absorbs more water but it is only the dough that appears drier. Thus after baking, a
heavy and poorly developed bread is obtained.

Gluten

The structure of breads and pizzas depends on the gluten.
In the dough phase, the gluten creates a sort of network inside the mass of water and flour
capable of retaining the starches and gases that develop during the leavening phase.
The properties of the dough are determined by the relative percentage of gliadin and glutenin:
the first makes it extensible (L), the second tenacious (P) and elastic.
The direct P/L ratio is one of the fundamental parameters for transformers and the optimal average values are between 0.5 and 0.6. Extreme values of 0.4 – 0.7 cause processing difficulties.
Flours with P/L = (0.4) are very extensible, sticky during processing and provide an underdeveloped bread because the gluten network does not retain the carbon dioxide produced by the yeasts.
Flours with P/L = 0.7 are very tenacious and difficult to knead, providing an underdeveloped bread.