Flour

For other uses, see Flour (disambiguation).

Three different kinds of wheat and rye flour.

Flour is a powder which is made by grinding cereal grains, other seeds or roots (like Cassava). It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history. Wheat flour is one of the most important foods in European, North American, Middle Eastern, Indian and North African cultures, and is the defining ingredient in most of their styles of breads and pastries. Maize flour has been important in Mesoamerican cuisine since ancient times, and remains a staple in much of Latin American cuisine. Rye flour is an important constituent of bread in much of central/northern Europe.

Etymology

The word "flour" is originally a variant of the word "flower". Both derive from the Old French fleur or flour, which had the literal meaning "blossom," and a figurative meaning "the finest." The phrase "fleur de farine" meant "the finest part of the meal," since flour resulted from the elimination of coarse and unwanted matter from the grain during milling.

History

A field of wheat prior to harvesting.

Main article: Wheat

It was discovered around 6000 BC that wheat seeds could be crushed between simple millstones to make flour. The Romans were the first to grind seeds on cone mills. In 1879, at the beginning of the Industrial Era, the first steam mill was erected in London. In the 1930s, some flour began to be enriched with iron, niacin, thiamine and riboflavin. In the 1940s, mills started to enrich flour and folic acid was added to the list in the 1990s.

Degermed and heat-processed flour

An important problem of the industrial revolution was the preservation of flour. Transportation distances and a relatively slow distribution system collided with natural shelf life. The reason for the limited shelf life is the fatty acids of the germ, which react from the moment they are exposed to oxygen. This occurs when grain is milled; the fatty acids oxidize and flour starts to become rancid. Depending on climate and grain quality, this process takes six to nine months. In the late 19th century, this process was too short for an industrial production and distribution cycle. As vitamins, micro nutrients and amino acids were completely or relatively unknown in the late 19th century, removing the germ was a brilliant solution. Without the germ, flour cannot become rancid. Degermed flour became standard. Degermation started in densely populated areas and took approximately one generation to reach the countryside. Heat-processed flour is flour where the germ is first separated from the endosperm and bran, then processed with steam, dry heat or microwave and blended into flour again.

The FDA has been advised by several cookie dough manufacturers that they have implemented the use of heat-treated flour for their ready-to-bake cookie dough products" to reduce the risk of E. coli contamination.

Production

Milling of flour is accomplished by grinding grain between stones or steel wheels. Today, "stone-ground" usually means that the grain has been ground in a mill in which a revolving stone wheel turns over a stationary stone wheel, vertically or horizontally with the grain in between. Many small appliance mills are available, both hand-cranked and electric. The mill stones frequently rub against each other resulting in small stone particles chipping off and getting into flour, but they are removed before the flour is sold.

Modern mills

Main article: Gristmill

Rollermills soon replaced stone grist mills as the production of flour has historically driven technological development, as attempts to make gristmills more productive and less labor-intensive led to the watermill and windmill. These terms are now applied more broadly to uses of water and wind power for purposes other than milling. More recently, the Unifine mill, an impact-type mill, was developed in the mid-20th century.

Composition

Flour being stored in large cloth sacks.

Flour contains a high proportion of starches, which are a subset of complex carbohydrates also known as polysaccharides. The kinds of flour used in cooking include all-purpose flour, self-raising flour, and cake flour including bleached flour. The higher the protein content the harder and stronger the flour and will produce crusty or chewy breads. The lower the protein the softer the flour for better cakes, cookies, and pie crusts.

Unbleached flour

Unbleached flour is simply flour that has not undergone bleaching and therefore does not have the color of "white" flour. An example of this would be the Graham flour. Sylvester Graham was against using bleaching agents, which he considered unhealthy.

Bleached flour

Main article: Flour bleaching agent

"Refined flour" has had the germ and bran removed and is typically referred to as "white flour". "Bleached flour" is any refined flour with a whitening agent added.

Bleached flour is artificially aged using a bleaching agent, a maturing agent, or both. A bleaching agent would affect only the carotenoids in the flour; a maturing agent affects gluten development. A maturing agent may either strengthen or weaken gluten development.

The four most common additives used as bleaching/maturing agents in the USA at this time are:

Potassium bromate (will be listed as an ingredient/additive) - a maturing agent that strengthens gluten development. Does not bleach.

Benzoyl peroxide - bleaches. Does not act as a maturing agent - no effect on gluten

Ascorbic acid (Will be listed as an ingredient/additive, but seeing it in the ingredient list may not be an indication that the flour was matured using ascorbic acid but instead has had a small amount added as a dough enhancer) - Maturing agent that strengthens gluten development. Does not bleach.

Chlorine gas - both a bleaching agent and a maturing agent, but one that weakens gluten development. Chlorination also oxidizes starches in the flour, making it easier for the flour to absorb water and swell - this makes thicker batters and stiffer doughs. For bread, this is bad (because gluten is weakened and bread is heavily dependent on gluten formation), but for cakes, cookies, and biscuits, it's a good thing, because gluten development in these types of baked goods makes them tough. The modification of starches in the flour allows the use of wetter doughs (making for a moister end product) without destroying the structure necessary for light fluffy cakes and biscuits. Chlorinated flour allows cakes and other baked goods to set faster, rise better, the fat to be distributed more evenly, with less vulnerability to collapse.

Cake flours in particular are nearly always chlorinated. There is at least one flour labeled "unbleached cake flour blend" (marketed by King Arthur) that is not bleached, but the protein content is much higher than typical cake flour at about 9.4% protein (cake flour is usually around 6% to 8%). According to King Arthur, this flour is a blend of a more finely milled unbleached wheat flour and cornstarch, which makes a better end result than unbleached wheat flour alone (cornstarch is a common additive for part of the flour used in cake where actual cake flour is called for but you only have all purpose on hand). However you will still get a denser end result than real cake flour that has been more finely milled, chlorinated, and has a lower protein content in the "cake flour" range of around 6% or so.

All bleaching and maturing agents (with the possible exception of ascorbic acid) have been banned in the EU, making cake baking a difficult proposition as heat treated flours that mimic the effects of chlorination are to date available only to bulk bakeries. The home baker in the EU must struggle with the unbleached flours that typically do not lend themselves to the making of light fluffy cakes. At least one home baker has developed a method for heat treating flour at home to break down the starches and make it more acceptable for use in the making of cakes; this process is currently referred to as "Kate Flour" in Internet baking communities, after the woman who continues to develop the process.

Bromation of flour in the USA has fallen out of favor and while it is not yet actually banned anywhere, few retail flours available to the home baker are bromated anymore.

Many flours packaged specifically for commercial bakeries are still bromated. Retail bleached flours marketed to the home baker are now mostly either treated via peroxidation or chlorine gas. Current information from Pillsbury is that their bleached flours are treated both with benzoyl peroxide and chlorine gas. Gold Medal states that their bleached flour is either treated with benzoyl peroxide OR it's treated with chlorine gas, but there is no way to tell which process has been used when you buy the flour at the grocery store.

Some other chemicals used as Flour treatment agents to modify color and baking properties include:

• chlorine dioxide (unstable to be transported in the U.S.)
• Calcium peroxide
• Azodicarbonamide or azobisformamide (synthetic)

• Atmospheric oxygen causes natural bleaching.

Plain flour

Flour that does not have a leavening agent is called plain or all-purpose flour. It is appropriate for most bread and pizza bases. Some cookies are also prepared using this type of flour. Bread flour is high in gluten protein, with 12.5-14% protein compared to 10-12% protein in all-purpose flour. The increased protein binds to the flour to entrap carbon dioxide released by the yeast fermentation process, resulting in a stronger rise.

Self-raising flour

Leavening agents are used with some flours, especially those with significant gluten content, to produce lighter and softer baked products by embedding small gas bubbles. Self-rising (or self-raising) flour is sold premixed with chemical leavening agents. The added ingredients are evenly distributed throughout the flour which aids a consistent rise in baked goods. This flour is generally used for preparing scones, biscuits, muffins, etc. It was invented by Henry Jones and patented in 1845. Plain flour can be used to make a type of self-rising flour although the flour will be coarser. Self-rising flour is typically composed of the following ratio:

• 1 cup (110 g) flour
• 1 teaspoon (3 g) baking powder
• a pinch to ½ teaspoon (1 g or less) salt

Enriched flour

Main article: Enriched flour

During the process of making flour nutrients are lost. Some of these nutrients are replaced during refining and the result is "enriched flour".

Common preservatives sometimes added to commercial flour

Calcium propanoate

Sodium benzoate

Tricalcium phosphate

Butylated hydroxyanisole

Types

Wheat flour

Main article: Wheat flour

More wheat flour is produced than any other flour. Wheat varieties are called "clean," "white," or "brown" or "strong" or "hard" if they have high gluten content, and they are called "soft" or "weak" flour if gluten content is low.

Other flours

A variety of types of flour and cereals sold at a bazaar in Bishkek, Kyrgyzstan

• Acorn flour is made from ground acorns and can be used as a substitute for wheat flour. It was used by Native Americans. Koreans also use acorn flour to make Dotorimuk
• Almond flour is made from ground almonds, suitable for people with gluten-free diets or Coeliac disease.
• 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 speciality food shops.
• Atta flour is a whole-grain wheat flour important in Indian and Pakistani cuisine, used for a range of breads such as roti and chapati.
• Bean flour is a flour produced from pulverized dried or ripe beans.
• Brown rice flour is of great importance in Southeast Asian cuisine. Also edible rice paper can be made from it.
• 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 crêpes bretonnes in Brittany. On Hindu fasting days (Navaratri mainly, also Maha Shivaratri), people eat items made of buckwheat flour. The preparation varies across India. The famous ones are Kuttu Ki Puri and Kuttu Pakoras. In most of northern and western states they call this Kuttu ka atta.
• Cassava flour is made from the root of the cassava plant. In a purified form (pure starch), it is called tapioca flour (see in list, below)
• Chestnut flour is popular in Corsica, the Périgord and Lunigiana for breads, cakes and pastas. It is the original ingredient for "polenta", still used as such in Corsica and other Mediterranean locations. Chestnut bread keeps fresh for as long as two weeks. In other parts of 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.
• Chuño flour made from dried potatoes in various countries of South America
• Coconut flour is made from ground coconut meat and has the highest fiber content of any flour, having a very low concentration of digestible carbohydrates makes an excellent choice for those looking to restrict their carbohydrate intake.
• Corn (maize) flour is popular in the Southern and Southwestern US, Mexico, Central America, and Punjab regions of India and Pakistan, where it called as Makkai Ka Atta. Coarse whole-grain corn flour is usually called corn meal. Finely ground corn flour that has been treated with food-grade lime is called masa harina (see masa) 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.
• Cornstarch is powdered endosperm of the corn kernel.
• Glutinous rice flour or sticky rice flour, used in east and southeast Asian cuisines for making tangyuan, etc.
• Hemp flour is produced by pressing the oil from the hemp seed, and milling the residue. Hemp seed is approximately 30% oil and 70% residue. Hemp flour doesn't rise, and is best mixed with other flours. Added to any flour by about 15-20%, it gives a spongy nutty texture and flavour with a green hue.
• Maida flour is a finely milled wheat flour used to make a wide variety of Indian breads such as paratha and naan. Maida is widely used not only in Indian cuisine but also in Central Asian and Southeast Asian cuisine.Though sometimes referred to as "all-purpose flour" by Indian chefs, it more closely resembles cake flour or even pure starch. In India, maida flour is used to make pastries and other bakery items such as bread, biscuits and toast.
• Mesquite flour is made from the dried and ground pods of the Mesquite tree which grows throughout North America in arid climates. The flour has a sweet, slightly nutty flavor and can be used in a wide variety of applications.
• Noodle flour is a special blend of flour used for the making of Asian style noodles. The flour could be from wheat or rice.
• Nut flours are grated from oily nuts — most commonly almonds and hazelnuts — and are used instead of or in addition to wheat flour to produce more dry and flavourful 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.
• Peasemeal or pea flour is a flour produced from roasted and pulverized yellow field peas.
• Peanut flour made from shelled/cooked peanuts is a higher protein alternative to regular flour.
• Potato starch flour is obtained by grinding the tubers to a pulp and removing the fibre and protein by water-washings. Potato starch (flour) is very white starch powder used as a thickening agent. Standard (native) potato starch needs boiling, to thicken in water, giving a transparent gel. 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.
• Potato flour, often confused with potato starch, is a peeled, cooked potato, mashed, mostly drumdried and ground potato flakes using the whole potato and thus containing the protein and some of the fibres of the potato; having an off-white slight yellowish colour. Dehydrated potatoes or instant mashed potatoes can also be granular, flakes. Potato flour is cold-water soluble.
• Rice flour is ground kernels of rice. It is used in Western countries and especially for people who suffer from gluten intolerance, since rice does not contain gluten.
• Rye flour is used to bake the traditional sourdough breads of Germany, Austria, Switzerland, Czech Republic, Poland and Scandinavia. Most rye breads use a mix of rye and wheat flours because rye does not produce sufficient gluten. Pumpernickel bread is usually made exclusively of rye, and contains a mixture of rye flour and rye meal.
• Sorghum flour is made from grinding whole grains of the sorghum plant. It is called jowar in India.
• Tapioca flour, produced from the root of the cassava plant, is used to make breads, pancakes, tapioca pudding, a savoury porridge called fufu in Africa, and is used as a starch.
• 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.

More types of flour

Main article: List of edible seeds

Flour can also be made from soybeans, peanuts, arrowroot, taro, cattails, acorns, quinoa and other non-cereal 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 is incinerated in a laboratory oven (typically at 550 °C or 900 °C, see international standards ISO 2171 and ICC 104/1). This is an easily verified indicator for the fraction of the whole grain remains 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%) leaves about 2 g ash or more per 100 g dry flour. Plain white flour (extraction rate: 50–60%) leaves only about 0.4 g.

• German flour type numbers (Mehltypen) 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, 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, and is generally from a softer wheat (this corresponds to what older French texts call "farine de gruau"). Some recipes use Type 45 for croissants, for instance, although many French bakers use Type 55 or a combination of Types 45 and 55. Types 65, 80, and 110 are strong bread flours of increasing darkness, and type 150 is a wholemeal flour.
• Czech flour types describes roughness of milling instead of amount of ash, though sometimes numbering system is used, it is not rule. Czechs determine following four basic types of mill: Extra soft wheat flour (Výběrová hladká mouka / 00), Soft wheat flour (Hladká mouka / T650), Fine wheat flour (Polohrubá mouka), Rough wheat flour (Hrubá mouka) and Farina wheat flour (Pšeničná krupice)

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 way for comparing the extraction rates of different available flour types.

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% (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	Italian	Czech
~0.4%	~9%	pastry flour	405	40	00	Hladká mouka výběrová 00
~0.55%	~11%	all-purpose flour	550	55	0	Hladká mouka
~0.8%	~14%	high gluten flour	812	80	1	Polohrubá mouka
~1%	~15%	first clear flour	1050	110	2	Hrubá mouka
>1.5%	~13%	white whole wheat	1600	150	Farina integrale di grano tenero	Pšeničná Krupice

This table is only a rough guideline for converting bread recipes. Since flour types are not standardized in many countries, the numbers may differ between manufacturers. Note that there is no Type 40 French flour. The closest is Type 45.

It is possible to determine ash content from some US manufacturers. However, US measurements are based on wheat with a 14% moisture content. Thus, a US flour with 0.48% ash would approximate a French Type 55. For US bakers of French pastry seeking an equivalent, for example, they could look at tables published by King Arthur Flour, showing their all-purpose flour is a close equivalent to French Type 55.

Other measurable properties of flour as used in baking can be determined using a variety of specialized instruments, such as the Farinograph.

Flammability

Flour dust suspended in air is explosive—as is any mixture of a finely powdered flammable substance with air (see flour bomb). Some devastating and fatal explosions have occurred at flour mills, including an explosion in 1878 at the Washburn "A" Mill in Minneapolis, the largest flour mill in the United States at the time.

Products

Bread, pasta, crackers, many cakes, and many other foods are made using flour. Wheat flour is also used to make a roux as a base for gravy and sauces. It is also the base for papier-mâché.

Cornstarch is a principal ingredient of many puddings or desserts.

References

• The Bread and Flour Regulations 1998, United Kingdom.
•  This article incorporates text from a publication now in the public domain: Ward, Artemas (1911). "The Grocer's Encyclopedia". The Grocer's Encyclopedia.

External links

• Cooking For Engineers - Kitchen Notes: Wheat Flour
• h2g2 entry on Bread Flour
• British Nutrition Foundation - Flour Information