We are going to look at these parameters together because they tend to be very common indicators of general flour quality but give only a little indication of how the flour is going to perform throughout the bake. They are great numbers to indicate whether you are getting the flour you think you need and can serve as a first point of reference if you think there are quality issues concerning your flour.

Moisture

On an analysis sheet this is a relatively simple number and is fairly meaningless to you as a baker. But it does give an indication of the quality stability of the flour as it was coming off the mill. Most moisture specifications read: ‘14% Max’. This means that the flour does not contain more than 14% moisture as it comes off the mill. This is important as flour containing moisture in amounts greater than 14% will tend to mold and spoil at a much quicker rate than drier flours. Flour is a hygroscopic material meaning that its moisture content will tend, over time, to equilibrate with the humidity of the surrounding environment. In damp conditions flour will absorb moisture from the environment and in drier conditions will lose moisture to the environment. So it is important to understand the time frame and storage conditions of your flour and realize that this will affect not only its quality but also the quantity of water that can be absorbed by the flour in the mixer bowl.

One final note, this moisture value is not indicative of flour absorption as indicated by the farinograph results.

Protein

Bakers are typically only interested in the gluten forming proteins of their flour. This measurement, however, is not a direct measure of gluten forming protein content, rather it is the total protein content of the flour. However, it can be used as a relative measure of the gluten forming protein content (ie the greater the total protein content the greater the gluten forming protein content). There has been much written about protein quality versus quantity. The percentage of protein as indicated on your analysis sheet only concerns quantity and really only serves as a general indication of the flour grade. The chart above indicates the broad categories of flour grades and even this is somewhat imprecise in that there is often a blurring of the lines between grades.

It is very important to note that most protein values in the US are reported on a 14% moisture basis whereas in the France and much of Europe protein (and ash) is reported on a 0% or ‘dry matter’ basis. This is a powerful tool and allows ‘apples to apples comparisons’ between flours that, as we discussed above, may have different moisture contents. It can, however, lead to confusion when you are talking about European flours and want to compare them to US flours. Basically, reporting on a 14% moisture basis gives you a corrected value of protein regardless of the actual moisture content. For those of you who must know here is the formula used for the correction:

Protein 14% m.b. = Protein % as is x (100 - 14) / (100 - Moisture Content)

This same formula is used to correct ash content to a 14% or ‘dry matter’ moisture basis.

Ash

Ash is another one of those ‘relative’ indicators of flour quality and is best used for ensuring the flour you are getting is the flour you want. The ash value for a particular flour is a measure of the mineral content of the flour. A 100g sample of flour is placed in an oven and incinerated at the temperature that combusts all of the organic mater but leaves the mineral content of the flour. This “ash” is weighed and then reported as the ‘ash content’ of the flour.

Most people use the ash value to determine how much bran has been left in the flour after the milling process. This is an indirect measure of bran content as there is some mineral content in endosperm as well. However, the mineral content of the bran layer is some 20 times greater than that of the endosperm. Therefore the ash value of a flour is a fairly good indicator of bran content in that the higher the ash value the greater the bran content and the darker the flour will appear. Bran in the flour also affects absorption. A higher ash value will indicate more bran in the flour which will result in an increase in absorption over flours with lower ash values.

As with protein, ash in the US is reported on corrected 14% moisture basis and in France on a dry matter (0% moisture) basis. Again this is very important to remember when requesting, say, a “T55” style flour from your US supplier. The “55” refers to the ash content of the French flour but is reported on a 0% moisture basis. So, throwing out all the other performance differences of a European T55 flour, the same flour in the US would actually have an ash content of approximately 0.46%.