The Anatomy of Wheat Flour
Shown directly above: Wheat Berry diagram. Shown at top : A golden Wheat Field. Provided by the Wheat Foods Council.
Wheat is a cereal grain. A member of the grass family, wheat fields look very similar to grass fields. Other cereal grains include corn, oats, rice, and rye. Consumption of cereal grains began in the Middle East about 10,000 years ago, where it was also first planted and cultivated. The seeds, called wheat berries or wheat kernels, are ground to create flour. Wheat Flour is technically defined as any flour milled from wheat.
The United States is a major wheat-producing country, with output typically exceeded only by China, the European Union, and India. Wheat ranks third among U.S. field crops in both planted acreage and gross farm receipts, behind corn and soybeans. About half of the U.S. wheat crop is exported. Wheat is the most popular cereal grain grown in the world for two important reasons; the first is because when flour is mixed with water (or other liquids), gluten is formed, which provides structure and rise in baked goods and other food products. Second, wheat is often preferred because of its mild, nutty flavor.
In general, flours types differ according to what part and how much of the wheat berry it contains. Wheat berries have three main parts: the bran, the endosperm and the germ. The bran is the hard, shell-like protective outer covering of the berry and is dark in color. Bran is high in dietary fiber—insoluble fiber, which improves intestinal health and is thought to reduce some cancers and soluble fiber, which lowers blood cholesterol and is thought to reduce the risk of heart disease. Bran also contains protein, minerals, fat and vitamin B. Bran proteins do not form gluten, they actually interfere with gluten development. Its sharp outer shell cuts gluten strands when batters and doughs are mixed and baked, yielding a denser, heavier baked product with less rise. Wheat bran can be purchased as small flakes and added to baked goods. They contribute to a dark, rustic appearance, nutty flavor, and the dietary nutrition mentioned above.
The endosperm makes up approximately 80% of the wheat berry. It is the whitest part of the berry because it contains mostly starch. The endosperm contains two proteins glutenin and gliadin and when mixed with water or other liquids form strands of gluten, (similar to a spider web). Gluten and its unique properties are key in providing structure and in turn, gives baked goods the ability to rise. It is responsible for making batters and doughs smoother and stronger and helps with the incorporation of any liquid. When batters and doughs bake in the oven, moisture is absorbed or evaporates by gelatinizing starch, and gluten sets into a firm, rigid, porous structure that holds its shape.
The germ is the embryo of the wheat berry. The germ makes up a small part of the wheat berry (about 2.5%), but is high in protein, fat, minerals, vitamin B and vitamin E. Germ does not produce gluten, so it does not contribute to any structure forming in baked goods; but it is often added to baked goods because of its high nutritional content. Wheat germ is typically toasted and contributes to the nutty flavor of wheat flour.
What’s the deal with White Bread, White Flour, Wheat Bread and Wheat Flour?
Shown above (from left): Bread made from White flour & Bread made from Whole Wheat flour. A typical loaf of bread made from Enriched Wheat & Whole Wheat flour.
White bread and brown bread — Image by © Royalty-Free/Corbis
Some bread labels include “wheat flour” as an ingredient. Wheat flour is not the same as Whole Wheat flour, although their names are similar. In the United States, whole wheat flour is a whole grain, milled from the entire wheat berry, meaning the bran, the endosperm and the germ. Whole wheat flour also has a host of nutritional benefits because of this. Wheat flour is simply another name for white flour, milled from only the endosperm. In comparison, Wheat flour (really White Flour), is mostly starch and has fewer nutritional benefits. It is called wheat flour to distinguish it from rye, corn, oat or rice flours. This information is often misleading to consumers who might confuse wheat flour with having the health benefits of whole wheat flour.
Likewise, wheat bread is not the same as 100% Whole Wheat Bread. Wheat bread typically, has Wheat Flour (really White Flour), as its main ingredient. A typical wheat bread contains a mixture of 60-70% white flour and only 25-40% Whole Wheat Flour. 100% Whole Wheat Bread, as its name indicates, contain only Whole Wheat Flour and yields nutritional value from the entire wheat berry. A typical wheat bread label, with ingredients listed in descending order may read as follows:
INGREDIENTS: ENRICHED WHEAT FLOUR (WHEAT FLOUR, MALTED BARLEY FLOUR, NIACIN, FERROUS SULFATE, THIAMIN MONONITRATE, RIBOFLAVIN, FOLIC ACID), WATER, HIGH FRUCTOSE CORN SYRUP, WHOLE WHEAT FLOUR, YEAST. CONTAINS 2% OR LESS OF EACH OF THE FOLLOWING: VITAL WHEAT GLUTEN, SALT, SOYBEAN OIL, SODIUM STEAROYL, LACTYLATE, CARAMEL COLOR
Notice Enriched Wheat flour (White flour) as the first ingredient, while whole wheat flour is further down the list of ingredients. Also notice corn syrup and caramel color added to the bread to create sweetness and brown color. Last, Vital Wheat Gluten is an ingredient, a dry powder form of naturally occurring protein found in wheat that increases mixing and fermentation tolerances, decreasing mixing and fermentation times. Vital Wheat Gluten improves rise and yields a finer crumb. It also contributes to a longer shelf life by keeping bread softer for a longer period of time. Care must be taken not to overdo the amount of vital wheat gluten added to bread formulas. Too much will produce a tough and chewy product.
What is Enriched Flour?
The milling process involves removing bran and germ from the endosperm. When this is done, vitamins and minerals, dietary fiber and protein and fat from the bran and germ are removed. It is likely that other important, unidentified nutrients are also removed. Flour enrichment replaces certain vitamins and minerals that are lost from milling. It does not replace the dietary fiber in bran, the high quality protein in the germ, or other potentially important yet unidentified nutrients in the bran and germ. Among other enrichments, Iron and Vitamin B are added in amounts equal to or exceeding that of whole wheat flour.
Flour enrichment began in the U.S. in the early 1940s after government surveys found that a high incidence of disease was caused by certain vitamin and mineral deficiencies. The enforced enrichment of white flour virtually eliminated two of these diseases, beriberi and pellagra.
The U.S. government periodically reevaluates the nutritional needs of North Americans. In the late 1990s, folic acid was added to the list of required vitamins and minerals added to enriched flour. Folic acid prevents certain birth defects, including spina bifida, and can also reduce the risk of coronary heart disease. Essentially all baked goods and pasta products made from white flour in the U.S. are enriched.
Though on the surface, enriched flour would seem healthy; there are arguments against the enrichment of flour. Some claim enriched flour is not absorbed by the body as wheat or a grain, in which case your body could use the energy slowly and effectively, but as a starch. Wheat germ is stripped from the flour and the FDA allows no more than 5% wheat germ in enriched flours. Wheat bran is also removed. When the human body ingests pure starch, it is the equivalent to ingesting pure sugar—leading to high, then low dips in sugar levels. Low sugar levels in human beings can lead to an increased appetite, loss in energy and obesity.
Whole grain or Whole Wheat flours are suggested as an alternative for the following reasons:
- Whole grain foods are higher in fiber because the wheat germ and bran have not been processed out of them.
- Whole grain foods are digested more slowly, because they are high in fiber, leaving you feeling fuller for a longer.
- Whole grain foods have more nutrients than “enriched” foods.
- Whole grains are not processed as a starch, so they don’t throw your body into a sugar dependency cycle.
Bleached vs. Unbleached.
Many flours are available bleached and unbleached. Unbleached flour, also called Unbromated flour, goes through a process called Natural Aging. Natural aging occurs when freshly milled flour is exposed to air for several weeks or more and results in two major changes: First, it whitens the flour. Second, it strengthens the gluten that forms from the flour. The active ingredient—oxygen, oxidizes the pigments in flour, changing the color to from a creamy white to a stark white. The chemical structures described above also occur due to oxidization.
The disadvantages of natural aging is it takes time and can be inconsistent or not as effective as chemical bleaching, but for consumers who prefer to not eat chemicals or risk having a chemical taste to a final product, natural aging may be preferred.
Bleached flour is usually treated with Chlorine or Benzoyl Peroxide. Bleached flour is typically treated with chlorine to mature the flour, condition the gluten and improve the baking quality. The chlorine evaporates and does not destroy the nutrients but does reduce the risk of spoilage or contamination. Benzoyl Peroxide is used on a variety of flours because it is extremely effective at whitening. It does not offer any flour maturing agents. The biggest difference between unbleached and bleached flour is the color; Unbleached flour is off-white and Bleached flour is pure white. The carotenoid (yellow) pigments in unbleached flours are oxidized to produce a whiter flour. Nutritionally, bleached and unbleached flour are the same.
A major argument against bleached flour claims that by treating flour with chlorine gas, poisonous byproducts are left behind in flour and later consumed. Moreover, there are no reasons for bleaching today. In the 1900s, bleaching stemmed from the need to quickly produce flour for consumption. Today, there is no need for quick production—America is not experiencing a famine and does not need to quickly mass produce flour.
Though still at issue, chlorine bleached flours continue to be produced and consumed in Canada, Australia, New Zealand, South Africa and the United States. Flours treated with these bleaching agents must be labeled as bleached.
Flour Classifications and Chracteristics.
Bakers classify wheat by the hardness of the wheat berry, that is, by whether the berry feels hard or soft to the touch. Hard wheat berries are high in protein; and Soft wheat berries are low in protein. There are many varieties of hard and soft wheat; both have winter and spring crops, each of which produce red and white varieties. Protein levels in flour are directly related to how much gluten can be formed using that particular flour. Gluten helps create structure and determine texture in your final baked good. Flours with low protein levels will generate less gluten and flours with high protein levels will create more.
To get the light and airy structure of cakes, you want a flour with very little protein. But to form the dense chewy structure of bread, you want a flour with a lot of protein so that you can create as much gluten as possible.
Below are the approximate protein levels and Wheat Berry types of all the common types of flour:
|High Gluten Flour||
13.5 – 14.5%
Hard Wheat berries
11.5 – 13.5%
Hard Wheat berries
|Whole Wheat Flour||
Hard Wheat berries
|White Whole Wheat||
Soft and Hard Wheat berries
9 – 11.5%
Hard and Soft Wheat berries
7 – 9.5%
Soft Wheat berries
6 – 8%
Soft Wheat berries
Typically, hard wheat flours form high quality gluten, meaning gluten stretches well and forms strong, cohesive films which result in structure and rise. Because they form strong gluten, hard wheat flours are considered Strong flours. Strong flours have high water (liquid) absorption rates, require longer mixing time to develop gluten and are more tolerant of over mixing. Strong flours are typically used in yeast raised products, such as breads, rolls, croissants and Danish.
Flours milled from soft wheat berries are whiter in color and finer to the touch than hard wheat flours. Soft wheat flours typically form weak gluten that tears easily, which is why they are referred to as Weak flours. Weak flours produce more tender products, such as cakes, cookies and pastries. Soft wheat flours are ground finer than hard wheat because the softness of their kernels allows this.
Common Flour Types and Characteristics
Whole Wheat Flour.
Description: Whole wheat flour (also called Graham or Entire wheat flour in the U.S. and Wholemeal flour in the U.K.), contains all three parts of the wheat berry. Whole wheat flour is considered a whole grain product (cereal, bread, etc.), only when all three parts of the wheat berry, in the same proportions as they occurred in the original wheat berry are milled to make the flour. Whole Wheat flour absorbs more water than White flour and has a shorter shelf life because the bran and the germ contain oil, which easily oxidizes to produce rancid, off flavors. Refrigeration of Whole Wheat flour will extend its shelf life.
Additional Characteristics: Whole Wheat Flour is typically milled from Hard Red Wheat. Whole Wheat Pastry Flour can be milled from Hard Red Wheat or Soft Red Wheat. Whole Wheat Flour is higher in protein than White Flour, but does not form as much gluten or rise in baked products as White Flour.
Whole Wheat Flour Performance: (1) The sharp bran particles in whole wheat flour cut through gluten strands as they form; (2) Bran is high in a carbohydrate called Pentosan Gums. High amounts of these carbohydrates interfere with gluten development resulting in less rise or lower volume in baked goods; (3) Much of the protein in Whole Wheat flour is from the bran and the germ, which do not form gluten; (4) Wheat Germ contains a protein that interferes with gluten development.
Summary: Products made with Whole Wheat flour will yield batters and doughs that are less cohesive and resilient. Products will yield less rise; will be more dense and coarse than other products made with white flour. Products will be darker in color, stronger in flavor, and provide positive health benefits. Whole Wheat flour is traditionally used for breads and other wholesome baked goods.
When substituting Whole wheat flour for White flour in a recipe for the first time, it’s best not to substitute more than one-third to one half of the white flour called for in recipes for whole wheat flour. This way the product will yield structural benefits from the white flour in addition to the nutritional benefits of whole wheat flour. Increase the proportion of whole wheat flour to white flour in later attempts, seeing how high you can go without compromising the texture of your product. Because Whole Wheat flour absorbs more liquid than White flour, the addition of water at about one tablespoon at a time, should be gradually included in a recipe until proper consistency of a dough or batter is reached.
White Whole Wheat Flour.
Description & Characteristics: Also called Whole Wheat White flour, this flour is made from soft or hard wheat and has been milled in the U.S. since the 1970s. White wheat is a different type of wheat that has no major genes for bran color. An easy way to think of it is as a sort of albino wheat. The bran of white wheat is not only lighter in color but it’s also milder in flavor, making whole white wheat more appealing to many people accustomed to the taste of white flour. It is milled from the entire wheat berry, bearing the same high amounts of dietary fiber as Whole Wheat flour. White Whole Wheat is widely used for whole grain breakfast cereals, baked goods and Asian noodles.
Protein levels are typically around 13%. Like Whole Wheat, White Whole Wheat does not provide as much gluten development or rise in baked products as White flour.
White Whole Wheat Performance & Summary: White Whole Wheat flour provides baked goods with an appearance of being baked with white flour, but still yields the nutrients of Whole Wheat flour.
White Whole Wheat flour can be substituted in cookie, muffin, quick bread, yeast bread and brownie recipes. Bread made from White Whole Wheat flour possess a milder taste and whiter color than bread baked with Whole Wheat flour. White Whole Wheat flour can be substituted for AP Flour, one to one. If more rise is desired, AP flour may be added to a recipe.
White Flour (AP Flour).
Description & Characteristics: White flour is commonly referred to as AP Flour for the home baker and Hotel and Restaurant flour (H&R flour) in the baking industry. White flour typically has 9.5 – 11.5% protein, but can vary depending on the brand. Some White flours are milled from a blend of hard and soft wheat, others are milled from only hard or only soft wheat. Regardless, White flour is milled from only the endosperm (mostly starch), and lacks the nutritional value present in Whole Wheat flours.
White Flour Performance & Summary: Baked goods cooked with only White flour yield the best and highest rise, mild taste and whiter color. White flour produces gluten development that is appropriate for pie doughs, breads, biscuits, cakes and cookies. Baked goods prepared with a mix of White flour and another flour will yield less rise than if prepared with only White flour. If substitutions are necessary, some recipes calling for AP flour may be substituted with a blend of cake and bread flour, usually a 60/40 or 50/50 blend.
Shown above: Loaf volume and crumb structure of breads containing different levels of lupin–soya and triticale: (1) 100% wheat flour; (2) 95% wheat flour and 5% lupin flour; (3) 90% wheat flour and 10% lupin flour; (4) 95% wheat flour and 5% soya flour; (5) 90% wheat flour and 10% soya flour; (6) 95% wheat flour and 5% triticale flour; (7) 90% wheat flour and 10% triticale flour. Provided by Science Direct.com. Remember Wheat flour in this case refers to White flour.
Definitions: Lupinus commonly known as Lupin or lupines, is a genus in the legume family. Soya fruit of the soybean plant is used in a variety of foods and as fodder (especially as a replacement for animal protein). Triticale a hybrid grain produced by crossing wheat and rye.
Description & Characteristics: Pastry flours are milled from soft wheat and/or soft white wheat. In either case, they are low in protein—typically 7 – 9.5% and are easily milled into fine granulation for a soft texture similar to baking powder.
Pastry Flour Performance & Summary: Batters and doughs made with Pastry flour remain relatively soft and fluid during the early stages of baking. This allows cookie doughs to spread farther, creating larger cookies; and allows cakes an opportunity to rise higher than with stronger flour. Pastry flour is not recommended for bread recipes, bread products will not look or taste the same than if prepared with bread flour. Bread dough made with pastry flour will be softer, with less structure; and once baked, bread will have less rise, color and shelf life.
Description & Characteristics: Cake flours are milled from soft wheat. Also referred to as High Ratio or Chlorinated flour, they are milled from the heart of the endosperm. This gives cake flour a finer granulation, whiter and brighter colored baked goods, a low protein content of 6-8% and low nutritional value. Cake flours are usually bleached with chlorine and benzoyl peroxide to obtain its white color and weaken gluten, making it a soft flour.
Cake Flour Performance & Summary: Cakes made from cake flour have good gluten development, thick batters, good rise and structure, because there is no interference from the bran and germ. Products in general yield a high rise, soft, tender crumb and moist texture. Cookies made from cake flour have cake like texture, better rise, brighter color and hold their shape better than those made from pastry flour.
Shown above (from left): Cookies made with Whole Wheat Pastry flour, Cookies made with Cake flour. Different flours in cookie dough result in differences in height and spread. Pastry flour yields a cookie with less rise/height and more spread. Cake flour produces a cookie with more height, tighter structure and a cake like texture. Photos provided by Eating Well.com, Ginger Crinkle Cookie recipe (left) and WhiteLightsonWednesday.com, Thin Mint Knock Off recipe (right), Thin Mint cookies stacked before being enrobed in chocolate.
Description & Characteristics: Bread flours are milled from Hard Wheat, are high in protein at 11.5 – 13.5% and form quality gluten—essential for high rise and fine crumbs in many baked good products. Because bread flours are milled from Hard Wheat, they are coarser in texture than other flours and darker in color.
Bread Flour Performance & Summary: Bread flours are typically used for pan breads, rolls, croissants, and sweet yeast doughs.
High Gluten Flour.
Description & Characteristics: High Gluten flours are milled from Hard Wheat and typically contain 13.5 – 14.5% protein. Potassium bromate or another bromated replacer is often added to produce stronger gluten. Potassium bromate is produced by passing bromine into a solution of potassium hydroxide. Alternatively, it can be created as a by-product of potassium bromide production by absorption of bromine from ocean water into potassium carbonate. Potassium bromate (KBrO3), is a flour “improver” that strengthens dough and allows for greater oven spring and higher rise in the oven. Potassium bromate, commonly referred to as simply “bromate” is a slow-acting oxidizer, contributing its functionality throughout mixing, fermentation and proofing stages, with important residual action during the early stages of baking.
High Gluten flours require higher amounts of water and mixing to fully develop gluten, but they can withstand over-mixing better than regular bread flours. High Gluten flours are sometimes bleached and can contain added malted flour. To learn how the addition of malted flour affects High Gluten flour, see footnote 2 below.
High Gluten Flour Performance & Summary: High Gluten flours are almost exclusively used for yeast raised baked goods, especially those requiring maximum strength and structure. High Gluten flours are best used for bagels, hearth breads, French breads, thin crust pizzas and hard rolls. Too much High Gluten flour will yield breads that are too chewy or too tough.
Functions of Flour: A Summary.
Structure. Flour is one of two main bakeshop ingredients that contribute to the toughening or structure building in baked goods, (eggs being the other). Structure allows products to hold a new, larger size and shape as gases expand to leaven and create rise in baked goods. It prevents products from collapsing during baking and cooling. Flour also provides structure, acting as a thickening agent to batters, doughs, pastry creams and pie fillings.
Flavor. Wheat flours have a relatively mild, nutty flavor that is generally considered desirable.
Color. Flours vary in color, and these colors determine the look of finished baked goods. Flour contributes to the browning of products and the interior color and texture of products.
Nutrition. Essentially all flours contribute complex carbohydrates (starch), vitamins, minerals and protein. White flours, made of only the endosperm have the least amount of health benefits and contain mostly starch. Whole wheat / Whole grain flours are made of the entire wheat berry—the bran, the germ and the endosperm, making it an excellent source of dietary fiber; and thought to reduce the risk of some cancers, heart disease and cholesterol.
Storage. All flours have a limited shelf life. The oxidization of oils when flour is exposed to air results in rancid, off flavors. To avoid problems, rotate flour stock by using older flour before using newer flour; and store all flour covered, in a cool dry area. This prevents the flour from absorbing moisture, odor and attracting insects or rodents. Wheat germ and whole wheat flour should be refrigerated if not used within a few months.
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Research Information and Photographs generously provided by the authors and institutions below. Find the following books and websites to get more meaningful, easy to comprehend information:
Figoni, Paula. How Baking Works, 3rd Edition. Hoboken, New Jersey: John Wiley & Sons, 2011
Chattman, Lauren. The Baking Answer Book: Solutions to Every Problem You’ll Ever Face; Answers to Every Question You’ll Ever Ask. North Adams, MA: Storey Publishing Company, 2009.
Gisslen, Wayne. Professional Baking, 6th Edition. Hoboken, New Jersey: John Wiley & Sons, 2012-2013
United States. United States Department of Agriculture. United States Department of Agriculture Economic Research. May 28, 2012.
Jackson, Ellen. “Flour Power: Hard or soft, red or white — or a blend?” Culinate.com. 16 April 2008. <http://www.culinate.com/articles/culinate8/flour_power
Huffington Post, Kitchen Daily. “Flour Guide: Which Types to Use for Baking.” 31 August 2012. <http://www.huffingtonpost.com/2012/03/30/guide-to-baking-flours_n_1388420.html>
Whole Grains Council, “Whole White Wheat FAQ.” 2012. <http://www.wholegrainscouncil.org/whole-grains-101/whole-white-wheat-faq>
King Arthur Flour. “Bromate Fact Sheet.” 2012. <http://www.kingarthurflour.com/professional/bromate.html>
Wikipedia. ” Potassium Bromate.” 11 December 2012. <http://en.wikipedia.org/wiki/Potassium_bromate>
Dr. Edward F. Group III, DC, ND. “The Hidden Truth About Enriched White Flour.” Global Healing Center, Natural Health & Organic Living. 28 May 2009. < http://www.globalhealingcenter.com/natural-health/enriched-white-flour/>
Phillips, Sarah. “Wheat Flour.” 2012. <www.baking911.com/bread/101_terms.htm>
 Potassium bromate has been banned from use in food products in the EU, Canada, Nigeria, Brazil, Peru and some other countries as it has been correlated with cancer . It was banned in Sri Lanka in 2001 and China in 2005.
In the United States, it has not been banned. The FDA sanctioned the use of bromate before the Delaney clause of the Food, Drug, and Cosmetic Act—which bans potentially carcinogenic substances— went into effect in 1958, so it is more difficult for it to now be banned. Instead, since 1991 the FDA has urged bakers to voluntarily stop using it. In California a warning label is required when bromated flour is used. (Wikipedia, last modified on 11 December 2012.)
 Malt powder or malt flour should not be confused with malted milk powder, often available in drink mixes like Horlicks®, Carnation Malted Milk®, and in some forms of Ovaltine®. True malt powder is usually made of barley. The process for producing the powder is to allow the barley to sprout for a short period of time, then to dry and finely grind the sprouted barley.
Malt powder or malt flour is present in numerous baked goods where it imparts a natural sweetness and results in browner color and shine. It also contributes to smoothness in batters and doughs, higher rises, and extended product shelf life. Information provided by Bob Red Mill’s Natural Foods and WiseGeek.org.