What is meant by the strength of flour?
Last time we talked about the function of the milling industry laboratory, which is responsible for quantifying the rheological characteristics of a product, of a grain and then of a flour produced with it. Specifically, these rheological values are different.
Today we are going to talk about what the W is, one of the evaluation elements regarding the choice of a flour for a certain type of processing over another. First of all, all these rheological values refer to and depend on a very important factor of the flour: the percentage of proteins and therefore the quantity of gluten.
These proteins influence in a positive or negative way what these rheological values are. Specifically, now let's talk about the W and the strength. The W is identified as a bread-making index or strength index or more commonly called the strength of the flour. What is meant by the strength of flour? It’s very simple. This refers to the resistance that a dough opposes to the mechanical action of the gases produced during leavening.?
Therefore, the stronger a flour, the more it will have a mechanical resistance and therefore to overcome this strength the gases will need more time to make this dough increase in volume. On the contrary, the lower the strength, the less time these gases will need to alter the characteristics of this dough and therefore to make it rise. As mentioned, this value influences the use of flour. But in what way?
If I have to make a product that has a very simple recipe, we are talking about a biscuit or a shortcrust pastry in that case I am going to use a product that has rheological characteristics of W therefore of very low strength, because in the biscuit, therefore in the composition of biscuit, in the shortcrust pastry, specifically, no resistance is required, you do not need a product that leavens excessively, but that leaven in a minimal way, due to the effect of the chemical liquid or because of the eggs present in the recipe. So there is a slight increase in volume and above all it must be a product that has a high friability, therefore the product with a low W is equivalent to a more crumbly and less resistant product and suitable for processing the biscuit.
Instead, the exact opposite is the processing of a large leavened product, such as the Christmas panettone or the Easter dove. It is a product that needs a very high W both because the recipe is very rich in ingredients, and because it needs a very resistant flour to withstand all that weight of product put inside, since a very complex recipe and therefore in that case a flour with a very high W is used.
This is the choice index for this kind of processing. Specifically, speaking of pizza or bread, we select, based on the programmed processing time, the flour with the W suitable for my processing times. So if you work the dough in the short term, you will have short maturations in the order of 6-12 hours and we will use a flour that has a very low W, since the dough needs a very low strength since in that time it must double in volume to be ready for cooking.
As for the speech W and the timing, we must also refer to the type of recipe chosen. So you go to use a very basic recipe, for a product that needs little hydration, or poor in ingredients, then you will use a flour that has a low W and therefore allows it to be processed in the short term.
For example a Roman round pizza, which is crunchy and which is very quick to make, then you can use a flour with a low W.
Instead, with a Roman pan pizza, then a product that has a slightly more complex recipe, since it needs very high gradations, a quantity of oil inside and a fairly marked alveolation, it must be made reference to flour with high W because it maintains its gluten mesh; therefore its strength allows it to withstand over the leavening gases, it also allows to withstand the recipe and the amount of water and oil that we are going to put.
In conclusion, the W influences both the processing time and the product: with products that need high hydration, marked alveolations and very long processing methods, then I have to choose a flour with a high W. With a basic processing with low hydration, unmarked alveolations and with a rather compact structure, then I will choose a flour with a low W.