There are many variations of flour derived from wheat on the market, but the distinction is not always so clear. In reality, the initial product is always the same: soft wheat, Triticum aestivumwhich goes through various milling and sieving processes, during which some parts of the wheat grain are eliminated. What is therefore changing is the degree of refinement: a more refined flour, and therefore more sifted, will be whiter. A less sifted, more raw one will be darker because it contains a greater percentage of brani.e. the outermost part of the wheat grain. From the most worked to the roughest we will have the order flour type 00, 0, 1 and 2, characterized by a different nutritional and protein content which also influences their use for more or less leavened doughs. In general, the more protein (gluten) a flour contains, the better it will rise. In wholemeal flours, however, the sieving phase is not carried out. Generally speaking, therefore, 00 flour is mainly used for fresh pasta, while the others are used for bread, focaccia or similar products.
How flour is obtained from wheat
Flour is the product obtained from grinding cereals. Specifically, in Italian legislation the “product obtained from and subsequent milling” is called “soft wheat flour”. sifting of soft wheat freed from foreign substances and impurities”. The origin is therefore soft wheat – Triticum aestivum – different from durum wheat from which semolina is obtained. The term sifting simply indicates the elimination of the bran from the flour using a special tool, the sifter.
Soft wheat produces a fruit called caryopsiswith the classic shape of an almond. The caryopsis is made up of three fundamental parts: endosperm, bran and germ.
The endosperm corresponds to the majority of the caryopsis and contains mostly starch and proteins.
The germ corresponds to a very small part of the grain (1.6-2% by weight) but is rich in nutrients such as lipids, proteins, vitamins. It is precisely this part that is generally separated during the production phase because these nutrients can compromise the shelf life of the flour. The remaining part of the caryopsis, the outermost one, is called bran and is rich in dietary fibre.
During the grinding, a machine with grooved rollers breaks and pulps these kernels with the aim of opening them, to detach the parts that compose them. We have millstones and grinders that are used to separate the flaky particles into flour. Subsequently there are the sieving operations, specifically called sifting. The final product is flour.
Flour 00, 0, 1 and 2: the Italian classification
According to Italian legislation, the percentage of flour distinguishes the various types of flour ashes maximum contained in the substance. The ash content, i.e mineral substancesis the lower the more the outer layers of the caryopsis are eliminated through the sieving phase. We therefore range from the more sifted – more refined – flours which are obtained almost exclusively from the endosperm portion of the caryopsis, up to the less sifted flours which instead contain a good part of bran.
Specifically the maximum percentage of ash contained in 100 parts of dry matter must be:
- 0.55 for 00 flour;
- 0.65 for 0 flour;
- 0.80 for flour 1;
- 0.95 for flour 2.
These values are also associated with a minimal amount of protein for each type of flour: from 9 parts out of 100 for 00 flours up to 12 parts out of 100 for 1 and 2 flours. The less refined the flour, the more protein it contains, as it contains more bran.
This difference in composition is not only relevant from a nutritional point of view. More protein (gluten) means more strength of the flour (W), i.e. the ability to absorb water when kneaded and retain the carbon dioxide that develops during leavening. “Strong” flours are those that absorb enough water to be suitable for doughs with medium-long leavening times. If we consider soft wheat flours, the strength of a flour is directly proportional to its quantity of proteins. For this reason, a very refined type 00 flour will be recommended for lightly leavened doughs such as pasta and biscuits, while type 0 or 1 flour will begin to appear in bread and focaccia recipes, which require significant leavening.
What about wholemeal flour?
The wholemeal soft wheat flour is obtained directly from grinding of soft wheat, without going through the sifting process. However, it is not made up of 100% ground wheat because Italian law imposes a quantitative limit on the ash in this case too. Specifically, the percentage of ash per 100 parts of dry matter must fall within the range of 1.30-1.70.
Small curiosity: in this article we talk about the classification of flour according to the law Italianbecause there is no nomenclature valid for the whole world. In other European states we will find other numbers to divide flours: for example we have “405, 550, 812…” in Germany or “T45, T55, T65…” in France. In America, however, packets of flour in the supermarket are not classified with a numerical value but with short descriptions: “all purpose, high gluten…”.
