As diets and societal trends have evolved, so has our use of wheat flour–a principle grain and staple food item in our everyday diet. The Economic Research Service (ERS) division of the UDSA estimates that U.S. per capita consumption of wheat flour averaged 137 pounds in 2008. This number is down from 225 pounds per person in 1879, yet is up from 110 pounds in 1972.1 Taking a closer look at the different types of wheat flours, will help you choose the best options for use in everything from sponge cake to pizza dough.
The wheat kernel, the seed of the wheat plant, is composed of three separate parts that are used or discarded during different stages of the milling process, depending on the type of flour being produced. The endosperm is the inner portion of the kernel and accounts for approximately 83 percent by weight of the wheat kernel.2 The endosperm is used to produce white flour and contains the greatest concentration of carbohydrates, protein (including gluten-forming proteins), soluble fiber and vitamins. The bran is the outer protective covering on the wheat kernel, accounting for about 14 percent by weight of the whole kernel, and is included when milling whole wheat flour.3 This hearty portion of the wheat kernel is largely desired for its high dietary fiber content as well as various vitamins and minerals. Making up only about 3 percent of the wheat kernel, the germ is the sprouting section (embryo) of the wheat seed that is extracted during white flour milling (yet generally included in whole wheat flour milling) since its nearly 10 percent fat content limits the shelf-life of wheat flour.4
While all wheat kernels are anatomically equivalent, there are variations among the plant. The first division is between spring and winter wheat, which are simply described by the season in which they are harvested. Winter wheat is most common because though it has slightly lower protein levels than the spring wheat, it is generally considered to be of a higher quality. The next division is between hard and soft wheat, the former of which has a higher protein content and the latter higher in starch. Finally, flour may be milled from the red or white wheat plant. Red is the original and most common type, while the white was added to the U.S. market within the last 20 years–marketed for its lighter color and milder, sweeter flavor profile. Flour millers use various combinations of spring/winter/hard/soft of either red or white wheat to create the desired flour profile, depending on the final application and the demands of the baking industry.
Now having a closer understanding of the wheat plant, let’s take a look at the different types of wheat flour that you are most likely to find:
- All-Purpose Flour – The most common type of flour sold, all-purpose flour is a balanced blend of hard and soft flours suitable for everyday use. This flour is sold and marketed mostly to the home cook as a go-to ingredient for a wide range of baked products such as cookies, cakes and pastries.
Many all-purpose flours are bleached with either benzoyl peroxide or chlorine gas, creating a pure white color and increasing the shelf life. Though this controversial chemical processing has not been proven to pose any health risks, bleaching removes the nutritional value naturally provided by the wheat endosperm, which is why wheat processors are required to re-enrich the flour with vitamins and minerals prior to selling. Unbleached flour is whitened naturally by oxidation during an air-aging process.
- Bread Flour – Typically ground from the endosperm of hard spring wheat kernels, bread flour has a higher protein and lower starch component than other flours.5 It is typically reserved for making breads and other yeast doughs.
- Cake Flour – This soft wheat flour has a very low protein content and is best suited for use in cakes, cookies and other pastries.
- Pastry Flour – Comparable to cake flour in its low protein content, pastry flour is less starchy than cake flour and therefore closer to all-purpose in its starch/protein balance.6 This flour is the most commonly used flour in most bakeries for a variety of pastry products.
- Gluten Flour – Processed from hard, high- protein wheat, this flour is commercially used by bakers who desire a higher protein content than bread flour. This is best used by experienced bakers who have developed a balance of gluten flour and other lower-protein flours in their recipes.
- Semolina – This flour is the coarsely ground endosperm of durum wheat7 (a specific wheat species that contains the highest known protein content of all wheat plants). Sometimes called “macaroni wheat,” semolina flour is most commonly used for pasta, couscous and other high-protein grain products.
- Whole Wheat Flour – Ground from the entire wheat kernel, whole wheat flour contains proteins, fat and fiber, which make it unique in baking. Baked products that utilize this type of flour are typically denser and much heavier than those using endosperm-only flours. The nutritional value of whole wheat flour has made it increasingly popular in today’s food market. If you would like to substitute it in some of your recipes, it is advised to not exceed a 50 percent replacement of other white flours.
- White Whole Wheat Flour – The same as whole wheat flour; however, it is milled from the entire kernel of the white wheat rather than the red wheat plant. This flour is desired for its lighter color and milder flavor, while maintaining an equal nutritional value to traditional whole wheat.
- Self-Rising Flour – All-purpose flour with added salt and leavening (baking soda/powder). This flour aims to streamline the baking process. In the case of substitutions with all-purpose flour, its proportions must be respected as follows: one cup of self-rising flour contains 1½ teaspoons baking powder and ½ teaspoon salt.
Resources
1 Economic Research Service/USDA. Wheat: Background. 17 March, 2009. Accessed 5/3/2010 from http://www.ers.usda.gov/briefing/wheat/background.htm.
2,3,4 The Wheat Foods Council: What is Wheat? 2010. Accessed 5/3/2010 from http://www. wheatfoods.org/AboutWheat-what-is-wheat/Index.htm.
5,6,7 The Wheat Foods Council: Wheat Flours. 2010. Accessed 5/3/2010 from http://www.wheatfoods.org/AboutWheat-wheat-flours/Index.htm.