Flour - Flour Type Numbers

Flour Type Numbers

In some markets, the different available flour varieties are labeled according to the ash mass ("mineral content") that remains after a sample is incinerated in a laboratory oven (typically at 550 °C or 900 °C, see international standards ISO 2171 and ICC 104/1). This is an easily verified indicator for the fraction of the whole grain remains in the flour, because the mineral content of the starchy endosperm is much lower than that of the outer parts of the grain. Flour made from all parts of the grain (extraction rate: 100%) leaves about 2 g ash or more per 100 g dry flour. Plain white flour (extraction rate: 50–60%) leaves only about 0.4 g.

• German flour type numbers (Mehltypen) indicate the amount of ash (measured in milligrams) obtained from 100 g of the dry mass of this flour. Standard wheat flours (defined in DIN 10355) range from type 405 for normal white wheat flour for baking, to strong bread flour types 550, 812, and the darker types 1050 and 1600 for wholegrain breads.
• French flour type numbers (type de farine) are a factor 10 smaller than those used in Germany, because they indicate the ash content (in milligrams) per 10 g flour. Type 55 is the standard, hard-wheat white flour for baking, including puff pastries ("pâte feuilletée"). Type 45 is often called pastry flour, and is generally from a softer wheat (this corresponds to what older French texts call "farine de gruau"). Some recipes use Type 45 for croissants, for instance, although many French bakers use Type 55 or a combination of Types 45 and 55. Types 65, 80, and 110 are strong bread flours of increasing darkness, and type 150 is a wholemeal flour.
• Czech flour types describes roughness of milling instead of amount of ash, though sometimes a numbering system is used, it is not a rule. Czechs determine following four basic types of mill: Extra soft wheat flour (Výběrová hladká mouka / 00), Soft wheat flour (Hladká mouka / T650), Fine wheat flour (Polohrubá mouka), Rough wheat flour (Hrubá mouka) and Farina wheat flour (Pšeničná krupice)

In the United States and the United Kingdom, no numbered standardized flour types are defined, and the ash mass is only rarely given on the label by flour manufacturers. However, the legally required standard nutrition label specifies the protein content of the flour, which is also a way for comparing the extraction rates of different available flour types.

In general, as the extraction rate of the flour increases, so do both the protein and the ash content. However, as the extraction rate approaches 100% (whole meal), the protein content drops slightly, while the ash content continues to rise.

The following table shows some typical examples of how protein and ash content relate to each other in wheat flour:

This table is only a rough guideline for converting bread recipes. Since flour types are not standardized in many countries, the numbers may differ between manufacturers. Note that there is no Type 40 French flour. The closest is Type 45.

It is possible to determine ash content from some US manufacturers. However, US measurements are based on wheat with a 14% moisture content. Thus, a US flour with 0.48% ash would approximate a French Type 55. For US bakers of French pastry seeking an equivalent, for example, they could look at tables published by King Arthur Flour, showing their all-purpose flour is a close equivalent to French Type 55.

Other measurable properties of flour as used in baking can be determined using a variety of specialized instruments, such as the Farinograph.