Wheat Flour 101 -- What Are You Buying?

By Trent J. Taylor – Blue Horizons Farm Inc - Jan. 30, 2009

To understand wheat flour, it is important first, to know the structure and makeup of the wheat kernel (berry) itself to understand the ingredients in each type of flour.  The following diagram shows a simplified cross section of a wheat kernel (berry):

The kernel (berry) is made up of three main parts as described below:

 Bran - About 14.5% of the kernel weight. The bran is included in whole wheat flour and is also available separately. The bran contains a small amount of protein, large quantities of the three major B vitamins, trace minerals and dietary fiber -- primarily insoluble.         

 Endosperm - About 83% of the kernel weight and the source of white flour. The endosperm contains the greatest share of protein, carbohydrates and iron, as well as [smaller amounts of] the major B-vitamins such as riboflavin, niacin, thiamin and iron. It is also a source of soluble fiber.

 Germ - About 2.5% of the kernel weight. The germ is the embryo or sprouting section of the seed, often separated from flour in milling because the fat content (10 percent) limits shelf life. The germ contains minimal quantities of high quality protein and a greater share of B-complex vitamins and trace minerals. Wheat germ can be purchased separately and is included in whole wheat flour. (It also includes antioxidants such as Vitamin E, etc.)

(Source - Montana Wheat and Barley Committee)

 Next, it is necessary to understand the different classes of wheat grown in the US from which different types of flour are made.  Following are descriptions of these classes:

 HARD RED WINTER -- Wide range of protein content, (11–12%) good milling and baking characteristics. Used to produce bread, rolls and, to a lesser extent, sweet goods and all-purpose flour.

 HARD RED SPRING -- Contains the highest percentage of protein (13-14%), making it an excellent bread wheat with superior milling and baking characteristics.

 SOFT RED WINTER -- High yielding, but relatively low protein (8-10 %). Used for flat breads, cakes, pastries, and crackers.

 HARD WHITE WHEAT (Winter or Spring) --The newest class of wheat to be grown in the United States. (Protein 11-14%) Closely related to red wheats (except for color genes), this wheat has a milder, sweeter flavor, equal fiber and similar milling and baking properties. Used mainly in yeast breads, hard rolls, bulgur, tortillas and oriental noodles.

 SOFT WHITE WHEAT -- Used in much the same way as Soft Red Winter (for bakery products other than bread). Low protein, (8-10 %) but high yielding. Produces flour for baking cakes, crackers, cookies, pastries, quick breads, muffins and snack foods.

 DURUM -- The hardest of all U.S. wheat.  Used to make semolina flour for pasta production.

(Source: The Wheat Grower/September-October 1994 – With some additions by the author.)

 Now we will divide wheat flour into two main categories:

 1.   Enriched White Flour

2.    Whole Wheat Flour (100% Whole Grain flour)

They are both made from wheat; however the processes used to mill the grain into flour are very different.  Enriched white flour requires a complex facility to produce; whole grain flour can be made at home with simple inexpensive equipment.

 Following are explanations of the two different processes.

1.  Enriched White Flour – the process in picture form:

 Source:  North American Millers Association (Notice this is a simplified version, in reality there are many rollers and sifters along the process on the right side of the above picture.)

 The purpose of this milling process is to separate the three main parts of the wheat kernel.  Bran and germ are separated and removed, leaving only the endosperm, the primary ingredient in white flour.

 The basics of milling enriched white flour are:

1.   Cleaning/washing to remove foreign objects

2.   Tempering with water - toughens the bran for easier separating and softens the    endosperm

3.   Break and reducing rollers (several) to crush wheat into smaller and smaller particles

4.   Purifiers - separate bran, shorts, and other unwanted parts of grain

5.   Sifters (several) - separate different sized particles of crushed grain

6.   Bleaching oxidizes flour to whiten, reduce pH, and enhance baking quality

7.   Enriching to add back some of nutrients lost from the bran and germ being removed

Why are these ingredients removed?

Wheat Germ - Even though the germ contains many essential nutrients and antioxidants, it also contains natural oil/fat (wheat germ oil) and once the germ is crushed and exposed to the air, the oil begins to oxidize and in time it becomes rancid.  Removal of the germ increases the shelf life of flour considerably and avoids the possibility of flour getting a strong flavor from rancid oils.  This also necessitates enriching, putting back into the flour some of the nutrients lost by removing the germ.

Bran – Bran contains most of the insoluble fiber in the wheat kernel, and interferes with the gluten development in breads.  The sharp edged bran particles interrupt the formation of gas bubbles created by yeast; thus generally a heavier and denser baked product is produced.

 2.  Whole Wheat Flour (100% Whole Grain Flour):

 Source:  Meadows Mills Inc

 The purpose of this grinding process is to grind the entire wheat kernel into flour.   All three parts of the wheat are still in this type of flour – bran, germ and endosperm. 

 After mechanically cleaning the wheat to remove foreign objects (similar to the left side of the above diagram), wheat is literally ground between two stones (could also be metal burrs) like the one directly above, one stone is stationary and the other is rotating.  Whole wheat is pulled into the center of the two stones and the ground flour is collected from the outside of the stones in a single process.  

 Wheat can also be ground in a high speed impact mill or hammer mill.  These mills contain fast moving metal teeth or hammers that shatter the whole kernel into flour.  Home flour mills can grind whole wheat flour of the same quality and fineness as commercial mills.  Below is a popular home impact mill on the market today.

 Source – pleasanthillgrain.com

 The following diagram helps explain the difference in the two different catagories of flour:

 Below are descriptions of different types of flour in each category

 Types of Enriched White Flour – Endosperm only

(Source - Wheat Foods Council)

 All Purpose Flour – Average protein and gluten content

All-purpose flour is the finely ground endosperm of the wheat kernel separated from the bran and germ during the milling process. All-purpose flour is made from hard wheats or a combination of soft and hard wheats from which the home baker can make a complete range of acceptable baked products --- yeast breads, cakes, cookies and pastries.

 Bread Flour – High protein and gluten content

Bread flour, ground from the endosperm of the hard red spring wheat kernel, is milled primarily for commercial bakers, but is now available bleached or unbleached at most grocery stores. It is usually enriched. Although similar to all-purpose flour, it has greater gluten strength and is generally used for yeast breads. (Sometimes has a small amount of malted barley flour added to help the yeast work better.)

 Cake Flour – Lowest protein and gluten content

Cake flour, milled from soft wheat, is especially suitable for cakes, cookies, crackers and pastries. It is low in protein and low in gluten.

 Pastry Flour – Low protein and gluten content

Pastry flour has comparable protein, but less starch than cake flour. It is milled from a soft, low gluten wheat and is used for pastries.

 Gluten Flour – High protein and gluten content

Gluten flour, processed from high protein wheat and containing much higher protein than bread flour, is used by bakers in combination with low protein or non-wheat flours. The gluten flour improves baking quality and produces yeast breads of high protein content.

 Vital Wheat Gluten (Not really flour) – Highest protein and gluten content - concentrated

Vital wheat gluten is derived from wheat flour and is the texture of flour; it is concentrated dried gluten protein with very little starch remaining.

 Semolina Flour – Highest protein and gluten content of any of any flour

Semolina is the coarsely ground endosperm of durum wheat.  High in protein, it is used by American and Italian manufacturers to make high quality pasta products such as macaroni and spaghetti.

 Durum Flour High in protein and gluten content

Durum flour is a by-product in the production of semolina and is used for American noodles, some types of pasta and occasionally in specialty breads.

 Treatments Made to Enriched White Flour - (Source - Wheat Foods Council)

 Enrichment or Fortifying

Enriched all-purpose flour has iron and B-vitamins (thiamin, niacin, riboflavin and folic acid) added in amounts equal to or exceeding that in whole wheat flour. The majority of all-purpose flour in the United States is enriched.

 Bleaching

Bleached all-purpose flour is exposed to chlorine gas or benzoyl peroxide to whiten and brighten flour color. Chlorine also affects baking quality by "maturing" or oxidizing the flour, which is beneficial for cake and cookie baking. The bleaching agents react and do not leave harmful residues or destroy nutrients.

 Unbleached

Unbleached all-purpose flour is bleached by oxygen in the air during an aging process and is off-white in color. Nutritionally, bleached and unbleached flours are equivalent.

 Self Rising

Self-rising flour is all-purpose flour with salt and leavening added. One cup of self-rising flour contains 1 1/2 teaspoons baking powder and 1/2 teaspoon of salt. Self-rising can be substituted for all-purpose flour in a recipe by reducing salt and baking powder according to these proportions.

 Bromated (Source – Wikipedia)

Bromated flour is flour with a maturing agent added.  The agent’s role is to help with the development of gluten; bromate is usually used; however other choices are phosphates, asorbic acid, and malted barley.  Bromate has been banned in much of the world, as it is a suspected carcinogen, but is still available in parts of the United States.

 Types of Whole Wheat Flour – All three parts of the kernel

 Traditional Whole Wheat Flour - High to medium protein and average gluten content

Also called Wholemeal Flour

Whole wheat flour (made from hard red wheat) is a coarse-textured flour containing the bran, germ and endosperm. The presence of bran reduces the gluten development, therefore, bake products make from whole wheat flour tend to be heavier and denser than those made from white flour.  Whole wheat flour is rich in B-vitamins, vitamin E and protein, and contains more trace minerals and dietary fiber than white flour. It also contains about five percent fat. (Source - Wheat Foods Council)

 “Light” or White Whole Wheat Flour - High protein and above average gluten content

Also called Unbleached Whole Wheat

Light whole wheat flour is made from hard white spring or winter wheat.  It has better baking qualities than traditional whole wheat flour, because it tends to rise better and has a sweeter milder taste.  It doesn’t rise as well as enriched white flour.  This flour is best for yeast breads because it has high elasticity and strength.  Can be used in place of enriched white flour in many recipes.

 Whole Wheat Pastry Flour – Low protein and gluten content

Whole wheat pastry flour is made from soft red or white wheat.   It is suitable for lighter texture pastries, cakes, cookies, pie dough, biscuits, etc. 

 Graham Flour – High to medium protein and average gluten content

Could also be called Reconstituted Flour

This term may be used as another name for traditional whole wheat flour.   True graham flour is made from hard red wheat and is different than whole wheat flour.  The three parts of the grain are separated (using the same process as enriched white flour) and ground separately; the endosperm is ground finely and the germ and bran are ground coarsely—then mixed back together (Not necessarily in the same proportions as whole wheat flour).  Sometimes the germ is NOT mixed back in to give the flour a longer shelf life, thus you have white flour mixed with bran.

 Whole Wheat Semolina Flour – Highest protein and gluten content of all whole wheat flour

This flour is made from durum wheat, the hardest variety of wheat grown.  It is used to make whole wheat pasta.  It has the highest gluten content of all wheat flours. 

 Treatments Made to Whole Wheat Flour

 Bolting

Whole wheat flour may be sifted (bolted) to remove much of the bran.  This flour may be called 20% flour, meaning that 80% of the bran has been sifted off, or could also be called reduced bran flour.   

 Enrichment or Fortifying

Some whole wheat flour may be enriched to add extra nutrients; however most whole wheat flour has nothing added.

General guiding principles in buying and using flour:

Freshness/Shelf Life:

Enriched White Flour

This flour should be kept in a sealed container and could be stored in the refrigerator.  Flour stored for longer that one year in unsealed containers may loose baking quality.

 Whole Wheat Flour

Freshness is much more important in purchasing whole wheat flour, the longer this flour sits the stronger will be the flavor as the natural oils become rancid.   It should be stored in a sealed container in the refrigerator or freezer to help curtail rancidity, if not, it is best to use this flour within 6 months of grinding.

  Uses of Flour:

 What do you want to make?                 Generally Use This Type of Flour

                                                  Enriched White Flour                Whole Wheat Flour

            Bread                          All Purpose Flour                        Light Whole Wheat Flour     

     (Want high protein)             Bread Flour                                Traditional Whole Wheat Flour

                                              Gluten Flour

                                                Vital Wheat Gluten

            Cake                         All Purpose Flour                        Light Whole Wheat Flour

     (Want low protein)             Cake Flour                                 Traditional Whole Wheat Flour   

                                Pastry Flour                         Pastry Flour

            Cookies                      All Purpose Flour                        Light Whole Wheat Flour

      (Want low protein)              Pastry Flour                               Traditional Whole Wheat Flour

                                                                                                Pastry Flour

            Pasta                            Semolina Flour                           Semolina Flour

                                                                                                Light Whole Wheat Flour

           Tortillas                        All Purpose Flour                       Light Whole Wheat Flour

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