Wheat is milled to remove the bran and germ, leaving the endosperm. The endosperm is the whitest part of the wheat grain, because it is 3/4 starch. From 100 pounds of wheat, 72 pounds of straight flour can be got (the other 28 pounds that is milled away is used for animal feed.) Still, it isn’t purely endosperm, as it will contain some particles of the bran and germ which cling so tightly to the endosperm that they weren’t removed in the milling. French bakers will use straight flour in their bread making; North Americans and British generally don’t.
Straight flour is separated by sifting in other grades. The straight flour is passed along a roller over different sieves. Different grades fall through the appropriate sieve along the roller. In the percentages given below, the lower the percentage of straight flour that falls through a particular grading sieve, the more desirable the flour.
Patent Flour is made from straight flour. It is the whitest flour class and the highest quality, as it is the grade of flour that contains mostly endosperm. That is where most of the protein is, which means good gluten developing properties. Patent Flour is divided into 5 categories:
- Extra Short Flour (aka Fancy Patent Flour): made from soft wheat, used for cake flour, contains 40 to 60 % of straight flour. Highest quality;
- First Patent Flour: made from soft wheat, contains 60 to 70% of straight flour;
- Short Patent Flour: made from hard wheat. Contains 70 to 80% of straight flour. For bread-making;
- Medium Patent Flour: 80 to 80 % of straight flour, bread making;
- Long Patent Flour: 90 to 95% of straight flour, bread making.
Clear Flour is made from what is left over from straight flour after the patent grade sieves have been passed over. Despite its name, it is actually the “darker” or “dirtier” flour.
There are three grades of Clear Flour: Fancy, First Clear and Second Clear. These flours are darker in colour than Patent Flours. They have a high ash content, the taste of which is desirable in rye breads.
- Fancy Clear Flour: used for pastry flour;
- First Clear: made from hard wheat, blended with lower-gluten flours. Often added to whole wheat or rye or other dark grain breads, where the darker colour of the clear flour won’t be noticed;
- Second Clear Flour: very dark, generally used for animal feed (e.g. dog and cat kibble, dog biscuits, etc..)
Low-grade Flour is made from straight flour. It is very dark. It is generally used for animal feed (e.g. dog and cat kibble, dog biscuits, etc..)
Stuffed straight flour is straight flour with some clear flour added.