guerrillafood

 I think we're talking about ash content.

here's some reference guidelines.

Ash content of a flour

“you can’t deduce the percentage of starch in the flour from the name: ”TYPE 405”.

This indicates the grinding degree and means:

That 405 mg ( milli grams...very small number) of minerals are left in the ashes after the burning test.

  Baking Science and technology 

The ash test is to determine the amount of mineral elements present in the flour, thus indicating the amount of bran still remaining in the flour after the milling process.

The lower the mineral content means a more refined flour.

Here’s how they do it

.

Modern Cereal Science and Technology

ASH:  this is determined on a 4gm sample in a silica dish which is incinerated overnight at 585 C. After cooling, the dish and ash are weighed , the ash brushed out, the dish re weighed and the weight of ash determined by difference. Results are reported as a per cent.

Examples:

All purpose and bread, type 55

High gluten, type 65

Light whole wheat; type 80

Whole wheat; type 110

Dark whole wheat; type 150

You see the pattern; the finer the flour, the lower the ash content. Pastry , having the lowest number and all whole wheat, the highest.

Same with rye flour.

Type 70 or 80 is light rye, medium rye is type 85, light pumpernickel is type 130 and dark pumpernickel rye is type 170

 Hope this is of help

Baker Henry in Vancouver Canada

Wow, I printed that out and am going to read it as I go to bed. Thanks Baker Henry for your help.

 considering that I'll be getting up in four hours, me too

You will find the info below in a more extensive entry on WikiPedia: http://en.wikipedia.org/wiki/Flour

In some markets, the different available flour varieties are labeled according to the ash mass ("mineral content") that remains after a sample was incinerated in a laboratory oven (typically at 550 °C or 900 °C, see international standards ISO 2171 and ICC 104/1). This is an easy to verify indicator for the fraction of the whole grain that ended up 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 (Mehltype) 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, 650, 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, but is generally from a softer wheat. Types 65, 80, and 110 are strong bread flours of increasing darkness, and type 150 is a wholemeal flour

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 suitable way for comparing the extraction rates of different available flour types.

Calvel's "The Taste Of Bread" has an extensive table on page 4 showing protein and ash content of US and French flours. The most important conclusion from that page (multiply types by 10 for german flours): 

• Type 45: Ash content below 0.50, extraction rate 67-70
• Type 55: Ash content 0.50-0.62, extraction rate 75-78
• Type 65: Ash content 0.62 - 0.75, extraction rate 78-82
• Type 80: Ash content 0.75 - 0.90, extraction rate 82-85
• Type 110: Ash content 1 to 1.20, extraction rate 85-90
• Type 150: Ash content above 1.40, extraction rate 90-98

Since American flour's ash content is measured based on a 14% flour humidity, ash content numbers cannot be compared directly. For example a French 0.55 ash (type 55) corresponds to a US 0.46 ash content flour. It is also pointed out that there are no direct equivalent flours between the French/German and US kinds and many US products do not list their ash content on the package.

The lack of ability to find equivalents is mostly due to the difference in milling process steps. Milling consists of a series of steps of grinding, sifting, and regrinding, gradually extracting the maximum amount of endosperm, while eliminating the bran. Each step produces a "stream" of flour (after the sifting). Each successive step processes more of the "outside" of the wheat kernel, so the first steps produces the weakest flours in terms of protein content. The final step(s) produce "clear" flours that are very strong and somewhat darker as they contain pieces of the bran. They are mostly considered useful to strengthen doughs where the percentage of rye flour is high and thus where color does not matter as much.

French flours are then constructed by mixing enough of all streams back together to get the desired ash content. US mills do not blend all streams, but rather select on the basis of desired resulting dough properties (strength). Thus a direct comparison of ash content does not mean equivalency. Also note that while higher extraction rate generally implies more of the outside of the endosperm, and thus high(er) protein content as well as ash content, the non-standardized blending taking place in US mills makes for a non-standard result.  Calvel prefers the medium protein content flours, either relatively high protein all purpose versions, or low protein bread flours. He deems these best for Artisan baking. I highly recommend this book, although expensive at around $80, if you want to get into the details of bread technology and French breads.

--dolf

See my My Bread Adventures in pictures

Man Thanks! I printed that out. Now I have something to read at work when things get slow. Thanks God I work in food. I can always read about the things I love at work, and it looks like I'm doing "research"; which I guess I am. But who knew you could actually enjoy your field of work?

...is Flour - a Treatise at www.theartisan.net/MainCommFrm.htm. This link may not take you directly to the page, however, click on "The Flour Treatise" in the menu and you'll see it.

Where can I find a list of Amerian flours to substitute for the various types of German flours? I fully understand that these substitutes will not be "perfect" - close is good enough for a starting point.

Thank you,

Pat