Flours for Pizza and Focaccia, the flour strength

The wheat ( Triticum aestivum ) comes from the Middle East. Its flour is the basis of many preparations : bread, pizza, cakes , pies , pastries , cookies , focaccie and so on . The largest producers of wheat are China, India, France, the U.S. and Russia . Italy in 2007 was in the 19th place  and  because of our insufficient to produce it,  we import 70% of the wheat we consume.

Classification of wheat flour

Here you can see a graphical representation of a wheat’s grain , or more precisely , a caryopsis. The outer skin , the covering , is the bran. Then we have the germ or embryo and finally the endosperm , which is the part that contains starch and proteins which form gluten. the bran is full of minerals, while the endosperm is full of starch. The Italian law has decided to classify the flour on the market based on the content of minerals. Or rather, they are classified according to the ashes , that is what remains after burning the flour. The Lower is the content of ash the more the flour will be  produced from the endosperm, so the flour will be white.

 The flour “integral” will instead have the maximum ashes content because the entire grain has been used so the flour will be darker than the flour produced with the endosperm.
The wheat flour is made up mostly of starch (64% -74 % ) and proteins ( 9 % -15 %), mainly glutenin and gliadin proteins . These , in contact with the water and through mechanical action , bind together and form a protein complex called gluten, creating a sort of elastic mesh . The gluten absorbs one time and half its weight in water , and during the rising retains the carbon dioxide developed by the yeast . The relative percentage of gliadin and glutenin determines the properties of flour: glutenins make it tough and resilient while gliadins make it extensible.

Flour Strength – W index

A device called Alveograph Chopin invented in 1921 by Marcel Chopin, provides an index called W that is now commonly used by professional bakers. W index measures the flour strength.

The maximum of the curve, identified by P, represents the toughness of gluten, while L represents the extensibility, the higher the value of L the more elastic the dough will be.

Flours between 90 and 160 W are called ‘ weak flours ‘ . They have a low proteins content , usually 9% , used to produce biscuits or cakes .

Flours between 160 and 250 W have a medium force . They are used for example for the Pugliese bread, pizza and focaccia .

In general, the more a product requires long rising time, the more a flour will need a high W, because it better retains the carbon dioxide produced in the fermentation . Gluten is able to absorb water for one time  and half  its weight , then the stronger the flour is, the higher will be the hydration. It passes from an hydration less than 50% for weak flour up to values ​​higher than 70 % for strong flour .

Special Flour – Manitoba Flour

Flours with a high W are called “strong flour ” because they oppose a great resistance to the deformation of gluten.. There are also flour with values ​​exceeding 400 W , denominated Manitoba originating because of that region of Canada. Manitoba are called even if the corresponding wheat is now grown in Europe. They have a high protein content and they are often used in a mixture with weaker flours to increase their strength.

Manitoba Flour is used to prepare Focaccia of Recco.

Relationship between W index and % of proteins

Unfortunately, the value ​​of W of a flour is not available on the common box of flour but we can see the amount of proteins on its label. On the table the relationship  between W index and proteins contained.
To prepare the cookies we avoid formation of gluten, so we have to use flour weak, low-protein and very extensible . Some preparations require very low percentages of protein , about 7% , and it is for this reason that the flour is mixed with starch and the product sold as ” preparation for cakes and sweet . “
To Preapre Pizza and Focaccie, you need of medium or strong flour , the stronger the flour is the longer the time rising will be and remember that the final volume of the product is proportional to the protein content of the flour.

Recipes of Pizza and Focaccia

Click here for Pizza, Focaccia and bread recipes

Sources

For this article I want to thank Dario Bressanini, a great Italian Scientific Food Blogger.