Types of Flour

The grading and classification of flour is usually based on a dry sample of flour which is burned to leave a risidual ash.  The percentage of relative weight of ash defines the type of flour (in the USA, the test is based on a 14% moisture content).   The standard test varies, but in France - 10 grammes  of dried flour are burned to give a residual ash content.  This is then repersented at a classification, so 0.55% ash would represent a T55 flour.  The German test used 100 grammes of dry flour to give 0.55% as a grade 550 flour  Other countries use this system but some apply local names or codes to the grades..

Roughly defined types    
Ash Content % Protein Content % Type of Flour (In UK)
0.40  9 Soft Flour
0.55 11 Plain Flour
0.80 14 Strong Flour
1.10 15 Very Strong Flour
>1.50 13 Wholemeal Flour

 The last three types of flour tend to have a higher gluten content and are therefore better to use for bread making.

Much of the protein content of the grain is in the germ and the husk.  The less the flour is refined, the higher the protein content will be.

Below is a table showing the classification of bread types for a number of example countries.

Country 100% grain 85% grain High Gluten flour White flour Very fine flour
United Kingdom Wholemeal Flour Brown Flour Strong Bread Flour Plain Flour Patent Flour
Germany Vollkorn 1600 1050 812 550 405
France Farine Integral 150 110 80 to 65 55 45
Spain / Portugal Harina Integrale 150 110 80 to 70 55 45
Italy Integrale Tipo 2 Tipo 1 Tipo 0 Tipo 00
Netherlands Volkorenmeel Gebuilde Bloem Tarwebloem Patentbloem Zeeuwse Bloem
Czech / Slovak Celozrnna Mouka Hrube Mouka Polohruba Mouka Hladka Mouka Hladka Mouka 00
Poland Razowa Sitkowa Chlebowa Luksusowa Tortowa
USA Wholewheat Flour First Clear Flour Bread Flour All Purpose Flour Pastry Flour
Argentina 1/2 0 0 00 000 0000
India Chakki Atta Atta - Maida / Sefed -
China - Quanmai Fen Gaojin Fen / Mianbao Fen Dijin Fen Dangeo Fen
Japan Zenryufun Kyorikimatsufun Kyorikiko Churikiko Hakurikiko

Both the USA and China fall outside of the overall classification scheme, so a comparison has been made to fit the flours into appropriate catagories.  Most of the flours produced in China are gluten free varieties made for the production of nudles, dumplings and other non bread products (not shown here).