Ash Content

Italian flour is classified by ash content. Ash content refers to the mineral content of a flour, and is determined by burning a given quantity of flour under prescribed conditions and measuring the residue. The mineral content varies and depends on many factors, such as the variety of wheat, the terrain, the fertilization, and the climate. The greater portion of minerals found in a kernel of wheat is contained in the germ, and husk, or bran, and the least amount in the endosperm. As a consequence, if a flour contains a greater number of bran particles, it has a more elevated ash content. The determination of the ash content serves to estimate the degree of the endosperm separation from the bran during milling, i.e. the grade of flour. Generally, flours thought to be of higher quality are more refined and produce less ash.

In spite of the fact that there is a positive correlation of ash content with the extraction rate of flour, and that European bakers make great use of this indicator,  Pyler (3) states:

"The ash content of flour cannot, however, be taken as an unequivocal index of flour extraction for two previously mentioned reasons: (a) the mineral content of wheat varieties cultivated under different growth conditions can vary markedly, and (b) not all wheat varieties have the same mineral content gradient from the peripheral tissues of the wheat kernel to the endosperm. Since the bran portions of wheat contribute to the color of flour, the objective measurement of flour color may be a more reliable indication of its quality"…

The following tables are provided for the readers general interest.  Table VI and table VII are excerpted from Il Manuale del Panificatore (5). Table VI compares Italian and German flour types relative to ash content.  Table VII describes French flour types according to ash content and extraction rate.  Table VIII is excerpted from Special and Decorative Breads (2), and compares French and American flour relative to ash content and extraction ratio.

Table VI

Italian Classification Extraction Rate German Classification
     
Type 00 50% Type 405
Type 0 72% Type 550
Type 1 80% Type 812
Type 2 85% Type 1200

Table VII

French Classification Extraction Rate Ash Content
     
Type 45 60 - 70 % < 0.5%
Type 55 75% 0.5 - .60%
Type 65 78 -  80% 0.62 - 0.65%
Type 80 85% 0.75 - 0.90%
Type 110 88 - 90% 1 - 1.20%
Type 150 95% 1.4%

Table VIII

Type (American/French) Approximate Extraction Rate Ash Content
     
Cake & Pastry/Type 45 70 % (65 - 75%) < 0.5%
All Purpose & Bread/Type 55 75% (70 - 78%) 0.5 - .60%
High-Gluten/Type 65 80% (74 - 82%) 0.62 - 0.75%
Light Whole-Wheat/Type 80 82% (78 - 85%) 0.75 - 0.90%
Whole Wheat/Type 110 85% (79 - 87%) 1 - 1.20%
Dark Whole Wheat/Type 150 90% (90 - 95%) 1.4%

 

Ash and Protein Comparisons: The United States and France

The following is a technical note about ash and protein percentages in flour of the United States and of France.  The figures below, originally found in Professor Calvel’s text, "The Taste of Bread"(*), are expressed as a percentage of dry matter, which is customary in France.  In the United States and Canada, figures are calculated on a basis of 14% flour humidity.  This means that a fairly normal seeming 11.5% protein French flour would in fact have a 9.5% protein content in North American terms, and that a high-seeming .62% ash would be .525 in North American terms.

Read the charts from top to bottom, then go to the next column and continue.  The charts are provided courtesy of National Baking Center, Minneapolis Minnesota.

0.65

Ash Content

USA

(14% Moisture)

France

USA

(14% Moisture)

France

USA

(14% Moisture)

France

 

 

 

 

 

 

0.40

0.48

0.55

0.70

0.83

0.65

0.41

0.49

0.56

0.67

0.71

0.85

0.42

0.50

0.57

0.68

0.72

0.86

0.43

0.51

0.58

0.69

0.73

0.87

0.44

0.52

0.59

0.70

0.74

0.88

0.45

0.54

0.60

0.71

0.75

0.89

0.46

0.55

0.61

0.73

0.76

0.90

0.47

0.56

0.62

0.74

0.77

0.92

0.48

0.57

0.63

0.75

0.78

0.93

0.49

0.58

0.64

0.76

0.79

0.94

0.50

0.60

0.65

0.77

0.80

0.95

0.51

0.61

0.66

0.79

0.81

0.96

0.52

0.62

0.67

0.80

0.82

0.98

0.53

0.63

0.68

0.81

0.84

1.00

0.54

0.64

0.69

0.82

0.85

1.01

 

Protein Content

USA

(14% Moisture)

France

USA

(14% Moisture)

France

USA

(14% Moisture)

France

USA

(14% Moisture)

France

 

 

 

 

 

 

 

 

 9.1

10.83

10.6

12.62

12.1

14.40

13.6

16.19

 9.2

10.95

10.7

12.74

 2.2

14.52

13.7

16.31

 9.3

11.07

10.8

12.86

12.3

14.64

13.8

16.43

 9.4

11.19

10.9

12.98

12.4

14.76

13.9

16.55

 9.5

11.31

11.0

13.10

12.5

14.88

14.0

16.67

 9.6

11.43

11.1

13.21

12.6

15.00

14.1

16.79

 9.7

11.55

11.2

13.33

12.7

15.12

14.2

16.90

 9.8

11.67

11.3

13.45

12.8

15.24

14.3

17.02

 9.9

11.79

11.4

13.57

12.9

15.36

14.4

17.14

10.0

11.90

11.5

13.69

13.0

15.48

14.5

17.26

10.1

12.02

11.6

13.81

13.1

15.60

14.6

17.38

10.2

12.40

11.7

13.93

13.2

15.71

14.7

17.50

10.3

12.26

11.8

14.05

13.3

15.83

14.8

17.62

10.4

12.38

11.9

14.17

13.4

15.95

14.9

17.74

10.5

12.50

12.0

14.29

13.5

16.07

15.0

17.86

 

 (*) Calvel, Raymond, James MacGuire, and Ronald Wirtz, "The Taste of Bread", Gaithersburg, MD; Aspen Publishers, 2001