Much more wheat flour is produced than any other flour.
Wheat varieties are called "white," or "brown" if they have high gluten content, and "soft" or "weak flour" if gluten content is low. "Hard flour," or "bread" flour, is high in gluten, with a certain toughness that holds its shape well once baked. Soft flour is comparatively low in gluten and so results in a finer texture. Soft flour is usually divided into "cake flour," which is the lowest in gluten, and "pastry flour," which has slightly more gluten than cake flour.
In terms of the parts of the grain (the grass seed) used in flour-the endosperm or starchy part, the germ or protein part, and the bran or fiber part-there are three general types of flour. White flour is made from the endosperm only. Whole grain or wholemeal flour is made from the entire grain including bran, endosperm, and germ. A germ flour is made from the endosperm and germ, excluding the bran.
- All-purpose or plain flour
- This flour is a blended wheat flour with an intermediate gluten level, which is marketed as an acceptable compromise for most household baking needs. It contains neither the bran nor the germ (Herbst 2001).
- Bleached flour
- This flour is treated with flour bleaching agents to whiten it (freshly milled flour is yellowish) and to give it more gluten-producing potential. Oxidizing agents are usually employed, most commonly organic peroxides like acetone peroxide or benzoyl peroxide, nitrogen dioxide, or chlorine. A similar effect can be achieved by letting the flour slowly oxidize with oxygen in the air ("natural aging") for approximately 10 days; however, this process is more expensive due to the time required.
- Bromated flour
- This is a flour with a maturing agent added. The agent's role is to help with developing gluten, a role similar to the flour bleaching agents. Bromate is usually used. Other choices are phosphates, ascorbic acid, and malted barley. Bromated flour has been banned in much of the world, but remains available in the United States.
- Cake flour
- This is a finely milled flour made from soft wheat. It has very low gluten content, making it suitable for soft-textured cakes and cookies. The higher gluten content of other flours would make the cakes tough.
- Graham flour
- This is a special type of whole-wheat flour. The endosperm is finely ground, as in white flour, while the bran and germ are coarsely ground. Graham flour is uncommon outside of the USA and the cities of Romania. It is the basis of true graham crackers. Many graham crackers on the market are actually imitation grahams because they do not contain graham flour or even whole-wheat flour.
- Pastry flour or cookie flour or cracker flour
- This flour has slightly higher gluten content than cake flour, but lower than all-purpose flour. It is suitable for fine, light-textured pastries.
- Self-rising or self-raising flour
- This is "white" wheat flour or wholemeal flour that is sold premixed with chemical leavening agents. It was invented by Henry Jones. It can also be substituted by Maida when cooking under the Indian Cuisine. Typical ratios are:U.S. customary:
- one cup flour
- 1 to 1½ teaspoon baking powder
- a pinch to ½ teaspoon salt
- 100 g flour
- 3 g baking powder
- 1 g or less salt
- Durum or semolina flour
- This flour is made of durum wheat. It has the highest protein content, and it is an important component of nearly all noodles and pastas. It is also commonly used to make Indian flatbreads.
In Britain, many flours go by names different than those from America. Some American flours and British equivalents include:
- Cake and pastry flour = soft flour
- All-purpose flour = plain flour
- Bread flour = strong flour, hard flour
- Self-rising flour = self-raising flour
- Whole-wheat flour = wholemeal flour
- Corn (maize) flour is popular in the Southern and Southwestern United States and in Mexico. Coarse whole-grain corn flour is usually called corn meal. Corn meal that has been bleached with lye is called masa harina and is used to make tortillas and tamales in Mexican cooking. Corn flour should never be confused with cornstarch, which is known as "cornflour" in British English.
- Rye flour is used to bake the traditional sourdough breads of Germany and Scandinavia. Most rye breads use a mix of rye and wheat flours because rye has a low gluten content. Pumpernickel bread is usually made exclusively of rye, and contains a mixture of rye flour and rye meal.
- Rice flour is of great importance in Southeast Asian cuisine. Also edible rice paper can be made from it. Most rice flour is made from white rice, thus is essentially a pure starch, but whole-grain brown rice flour is commercially available.
- Noodle flour is special blend of flour used for the making of Asian style noodles.
- Buckwheat flour is used as an ingredient in many pancakes in the United States. In Japan, it is used to make a popular noodle called Soba. In Russia, buckwheat flour is added to the batter for pancakes called blinis which are frequently eaten with caviar. Buckwheat flour is also used to make Breton crepes called galettes.
- Chestnut flour is popular in Corsica, the Périgord, and Lunigiana. In Corsica, it is used to cook the local variety of polenta. In Italy, it is mainly used for desserts.
- Chickpea flour (also known as gram flour or besan) is of great importance in Indian cuisine, and in Italy, where it is used for the Ligurian farinata.
- Teff flour is made from the grain teff, and is of considerable importance in eastern Africa (particularly around the horn of Africa). Notably, it is the chief ingredient in the bread injera, an important component of Ethiopian cuisine.
- Atta flour is a wheat flour which is important in Indian cuisine, used for a range of breads such as roti and chapati.
- Tang flour (not to be confused with the powdered beverage Tang) or wheat starch is a type of wheat flour used primarily in Chinese cooking for making the outer layer of dumplings and buns.
- Glutinous rice flour or sticky rice flour, used in east and southeast Asian cuisines for making tangyuan, and so forth.
- Peasemeal or pea flour is a flour produced from roasted and pulverized yellow field peas.
- Bean flour is a flour produced from pulverized dried or ripe beans.
- Potato flour is obtained by grinding the tubers to a pulp and removing the fiber by water-washings. The dried product consists chiefly of starch, but also contains some protein. Potato flour is used as a thickening agent. When heated to boiling, food added with a suspension of potato flour in water thickens quickly. Because the flour is made from neither grain nor legume, it is used as substitute for wheat flour in cooking by Jews during Passover, when grains are not eaten.
- Amaranth flour is a flour produced from ground Amaranth grain. It was commonly used in pre-Columbian Meso-American cuisine. It is becoming more and more available in specialty food shops.
- Nut flours are ground from oily nuts-most commonly almonds and hazelnuts-and are used instead of or in addition to wheat flour to produce more dry and flavorful pastries and cakes. Cakes made with nut flours are usually called tortes and most originated in Central Europe, in countries such as Hungary and Austria.
Flour can also be made from soy beans, arrowroot, taro, cattails, acorns, peas, beans, and other non-grain foodstuffs.
Flour type numbers
In some markets, the different available flour varieties are labeled according to the ash mass ("mineral content") that remains after a sample was incinerated in a laboratory oven (typically at 550 °C or 900 °C). This is an easy to verify indicator for the fraction of the whole grain that ended up in the flour, because the mineral content of the starchy endosperm is much lower than that of the outer parts of the grain. Flour made from all parts of the grain (extraction rate: 100 percent) leaves about 2 grams ash or more per 100 grams dry flour. Plain white flour (extraction rate: 50-60 percent) leaves only about 0.4 grams.
- German flour type numbers (Mehltype) indicate the amount of ash (measured in milligrams) obtained from 100 g of the dry mass of this flour. Standard wheat flours (defined in DIN 10355) range from type 405 for normal white wheat flour for baking, to strong bread flour types 550, 650, 812, and the darker types 1050 and 1600 for wholegrain breads.
- French flour type numbers (type de farine) are a factor 10 smaller than those used in Germany, because they indicate the ash content (in milligrams) per 10 g flour. Type 55 is the standard, hard-wheat white flour for baking, including puff pastries ("pâte feuilletée"). Type 45 is often called pastry flour, but is generally from a softer wheat. Types 65, 80, and 110 are strong bread flours of increasing darkness, and type 150 is a wholemeal flour.
In the United States and the United Kingdom, no numbered standardized flour types are defined, and the ash mass is only rarely given on the label by flour manufacturers. However, the legally required standard nutrition label specifies the protein content of the flour, which is also a suitable way for comparing the extraction rates of different available flour types.
It is possible to find out ash content from some US manufacturers. However, US measurements are based on wheat with a 14 percent moisture content. Thus, a US flour with .48 ash would approximate a French Type 55.
In general, as the extraction rate of the flour increases, so do both the protein and the ash content. However, as the extraction rate approaches 100 percent (whole meal), the protein content drops slightly, while the ash content continues to rise.
The following table shows some typical examples of how protein and ash content relate to each other in wheat flour:
Ash Protein Wheat flour type US German French ~0.4% ~9% pastry flour 405 45 ~0.55% ~11% all-purpose flour 550 55 ~0.8% ~14% high gluten flour 812 80 ~1% ~15% first clear flour 1050 110 >1.5% ~13% white whole wheat 1600 150
This table is only a rough guideline for converting bread recipes. Since the American flour types are not standardized, the numbers may differ between manufacturers.
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