All About Flour

Cultivated wheat can be categorized into two types: hard and soft. This classification refers to the hardness of the wheat berry itself, and also the amount of protein in the wheat berry. The northwestern U.S. and western Canada produce hard wheat very high in protein, while the southern states grow a more soft wheat, which contains less protein.

The wheat berry is composed of essentially three parts: the bran, the germ, and the endosperm.

• The bran is the hard outer shell that covers the wheat berry. An excellent source of fiber, the bran also contains most of the minerals found in wheat. Because the bran has sharp edges, which interfere with gluten development, it is removed during milling. You will have to add it separately to enjoy its benefits.
• The germ is the part of the grain that would become the plant, if cultivated. Wheat germ is very high in protein and B vitamins. It is removed in the milling process because it causes the flour to become rancid more quickly, due to its high fat content. Wheat germ should be stored in the refrigerator.
• The endosperm is the food that the seed would consume to become a plant. The flour that we use for baking, unless it is whole wheat, has had the germ and the bran removed. The remaining endosperm is composed mostly of starch and protein.

There are many types of bread flours made from hard wheats and soft wheats, with such descriptors as "first clear flour," "patent flour," and "high gluten flour." As a home baker, you'll be fine with the blend of flour found in any national brand.

Why use bread flour?

• To make bread, you need a high-protein flour in order to get a decent rise out of your loaf. Gluten is formed by two of the proteins found in wheat, glutenin and gliadin.
• When combined with water and developed by mixing and kneading, gluten becomes stretchy and elastic. It stretches around the gas bubbles produced by the yeast in bread, and maintains the structure formed when gas bubbles expand in the oven.
• Wheat is the only grain that has these gluten-producing proteins. For this reason, breads made with other grains--such as rye, corn, or oats--must be fortified with wheat flour or gluten to rise properly.

One cup of bread flour = 4.8 oz (136 g)

All-purpose flour has been formulated to allow home bakers to make a wide variety of products--cookies, muffins, quick breads, biscuits, cakes, and pie crusts--without having to stock up on multiple types of flour. If you enjoy baking and start making breads or cakes regularly, you might want to use specialty flours.

Note: The natural oils in flours, especially whole grain flours, can spoil and turn rancid. Flour should be stored in the refrigerator or freezer if you bake infrequently. It should smell and taste "wheaty," not musty or stale.

One cup of AP flour = 4.5 oz (128 g)

Why use pastry flour?

• This medium-protein flour produces tender pie crusts. If you use a flour with too much protein, your pastry can become tough; too little, and the pastry can be brittle and hard to work with.
• In a pinch, you can make your own version of pastry flour by combining one part cornstarch to two parts all-purpose flour.

One cup of pastry flour = 4.25 oz (120 g)

Cake flour is not just a lower-protein flour--it's also bleached with chorine, which alters the structure of the starches and fats and makes the flour slightly acidic. For best results, don't substitute all-purpose flour in recipes that have been formulated for cake flour. Always sift cake flour before using it in a recipe.

One cup of cake flour = 3.9 oz (111 g)

Whole wheat flour contains all of the nutrients found in the wheat kernel and results in dense, hearty baked goods. Some people find that 100% whole wheat bread tastes a little bit too healthy, however. So if you're not used to baking with whole wheat flour, start by substituting half whole wheat, half bread flour in your recipes.

Note: You might need to adjust your liquids to hydrate the flour fully (use more water if you're adding whole wheat flour to a recipe, less if you're substituting bread flour for whole wheat).

One cup of whole wheat flour = 4.25 oz (120 g)

Self-rising flour is used for quick breads, biscuits, muffins, and pancakes. It already contains baking powder, so don't add any other leavening agents.

• To make your own self-rising flour, add 1½ tsp baking powder per cup of flour (or 5-7 g of baking powder per 100 g of flour).

Special bread machine flours are generally just high-protein flours, although some brands might contain dough conditioners like malted barley flour (diastatic malt powder), ascorbic acid, or lecithin.

Freshly ground wheat might smell great, but it doesn't make an optimum loaf: as flour ages, it creates stronger gluten, resulting in a more elastic dough and a lighter loaf of bread. Aging also changes the color of flour from pale yellow to white. Millers began speeding up this aging process with chlorine and potassium bromate, which also helped the flour look whiter. Because of health concerns, bromate is no longer widely used as a bleaching agent: ascorbic acid (vitamin C) is used instead.