Flour Quality

Quality of flour is defined by its ability to consistently perform in the production of a finished baked good.  The ultimate quality test is completed when the baker uses the flour.  

Because there are a limitless number of baked goods that can be derived from a single flour, it is an impossible task for the miller to test every application.  Millers, therefore, rely on a few standardized baking applications.  Tests are completed based on the application that best suits the particular flour.

Patent bread flours will be tested in pan breads, high gluten flours in hearth breads, cake flour in high ratio cakes, etc.  The test methodology, formula and conditions are all controlled and kept constant.  The only thing that changes is the flour that is used.

The miller will record such measurements as loaf volume, crust color, crumb color, texture, etc.  This way the miller is able to determine the effect of the flour on the performance of the finished baked good and make any necessary adjustment to maintain consistency.  

Gluten is developed from flour protein.  When combined with water under mixing stress, the proteins in the flour will form gluten, which provides extensibility, elasticity and gas-retaining properties to yeast-leavened baked goods.  The quantity of gluten is proportionate to the amount of protein in the flour, so gluten increases as the protein content increases.

Wheat flour is unique because it is the only cereal grain that possesses gluten-forming proteins – gliadin and glutenin.  These comprise roughly 80 percent of the total wheat protein.  The remaining proteins in flour are non-gluten forming and contribute nothing to dough strength.

The major flour types and their relative protein levels are: High Gluten 13.5-14.5%; Bread 12-13%; All Purpose 10-12%; Pastry 8-10%; and Cake 7-9%.

Once we have reviewed the characteristic of wheat flour protein to form gluten, the question arises that if we buy flour with a higher protein content (quantity), can we bake a better (quality) product?  This is not always the case.  High quality, low quantity protein flour will outperform a high quantity, low quality flour in producing acceptable baked goods.  

Whole wheat is a great example – it can have a protein quantity between 13.5 and 15 percent.  This is a higher protein range than high gluten flour (13.5 to 14.5 percent).  Will the whole wheat flour  outperform the high gluten?  No.  The bran and the germ are rich in non-gluten forming protein, which will contribute to the overall protein quantity, not quality.  

In relative terms, protein quantity can be used as a predictor of the suitability of flour in specific baking applications.  But the protein content of a flour can be affected by many agronomic factors, such as amount of rainfall, fertilizer usage, temperature stressed, etc.  A quality miller is going to balance protein quantity with the appropriate quality testing to prepare the best flours available for specific baking needs.  So how do we measure protein quality?  

Protein quality can be measured indirectly with dough-testing devices such as the farinograph. The farinograph curve provides useful information regarding the strength, mixing tolerance and absorption characteristics of flour. This instrument measures the resistance of flour and water dough to mechanical mixing. The resistance is recorded as a graph. The shape of the curve indicates the strength of the flour.

From the graph, a technician can determine a few key measurements: Arrival Time is the time it takes the curve to reach a standard resistance line.  This value represents the rate of hydration of the flour.  Peak Time is the time required for the dough to reach full development. The measurement can be a predictor of optimum mixing time.  Stability Time is the amount of time the curve stays above the standard resistance line.  This value will relate to the tolerance of the flour to mixing. Absorption is the amount of water required to create dough that will center itself on the standard resistance line.  The value is not necessarily the true formulation absorption for the baker.  Mixing Tolerance Index is the distance the curve drops five minutes after it has reached the full development peak. This value will relate to the rate at which the flour breaks down under mixing stress.


Most flour specifications include values for protein and ash.  Previously, we spoke of the importance of protein both quantitatively and qualitatively.  Ash, although frequently used as a quality specification for flour, is best suited as an indicator of the degree of wheat milling. It is truly not a reliable index of flour’s baking quality.  

Ash is the mineral residue of the flour left after complete combustion of a sample. The minerals are spread throughout the entire wheat kernel but are more concentrated in the bran layer than in the endosperm.  Therefore, ash is used as the measure of the degree of bran separation from the endosperm during milling.  

The objective of the miller is to separate the endosperm from the bran as completely as possible. Extraction is the term used to describe the percentage of the wheat kernel that is milled into flour.  On average, 73-76 percent of the wheat ends up as white flour. The ash test allows the miller to monitor their efficiency of milling. The closer the miller gets to the bran level, the higher the ash level becomes. Higher extraction will result in higher ash levels.

The total mineral content of wheat ranges from one to two percent.  The inorganic minerals of wheat are supplied through the soil.  Thus, wheat will vary in mineral (ash) content due to differences in wheat variety, soil conditions, rainfall, fertilization and other agronomic factors.  Some wheat varieties possess high amounts of mineral content in the endosperm, thus producing higher ash flour.  Ash is expressed as a percentage and can range from .35 percent for cakes and flours, up to .65 percent or more for clear flours.

Ash is a rough indicator of flour color since the bran does contribute to flour color.  Flour color also is affected by granulation and bleaching, although bleaching is ineffective on the bran itself.  Ash alone is not and never has been a reliable measure of flour’s performance in terms of baking quality.  It is a very meaningful measurement for the miller in terms of milling efficiency and maintaining the consistency of flour extraction.