Other Flour Classification

In some countries, flour is sold according to the “ash” or mineral content that remains after a sample is incinerated in a laboratory oven at very high temperature. It is an easy to use indicator as there is less mineral content in the endosperm or white of the grain than the woody or starchy outer bran. Therefore the lower the ash content the whiter or purer the flour. Wholemeal Flour (extraction rate: 100%) leaves 1.5% -  2% ash or 2g per 100g dry flour. Plain white flour at a 75% extraction, leaves only about 0.4% ash (0.4g/100g).

• German flours indicate the amount of ash in milligrams per 100g of flour. Standard wheat flours range from type 405 for normal white wheat flour for baking, to strong bread flour types 550, 650, 812, and the darker types 1050 and 1600 for wholegrain breads and even higher for the classic German rye flours 1350 or 970 for Dark or light Rye Flours.

• French flours (type de farine) indicate the ash content in milligrams per 10g flour, a factor of 10 less than German flours. The standard French white hard-wheat flour is Type 55 used for baking the classic French loaves.  French flours range up to Type 150 for a wholemeal and lower – Type 45 for a typical pastry flour.

In both UK and the USA such a scientific scale is not used and it is rare for ash to be used or even measured, particularly in the UK. However labelling laws require that a minimum level of nutritional information is clearly displayed in the label.  This specifies the protein level for example and this is a good indicator of the best application of the flour in baking.