Bread
Bread
| Bread, white (typical) Nutritional value per 100 g (3.5 oz) |
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| Energy 270 kcal 1110 kJ | ||||||||||||||||
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| Percentages are relative to US recommendations for adults. |
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| Bread, whole-wheat (typical) Nutritional value per 100 g (3.5 oz) |
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| Energy 250 kcal 1030 kJ | ||||||||||||||||
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| Percentages are relative to US recommendations for adults. |
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Bread is a staple food prepared by cooking a dough of flour and water and possibly more ingredients. Doughs are usually baked in the Western world (and many other countries), but in some cuisines breads are steamed, fried, or baked on a hot skillet.[1] It may be leavened or unleavened. Salt, fat and leavening agents such as yeast and baking soda are common ingredients, though bread may contain other ingredients, such as milk, egg, sugar, spice, fruit (such as raisins), vegetables (such as onion), nuts (such as walnuts) or seeds (such as poppy seeds). Bread is one of the oldest prepared foods, dating back to the Neolithic era. The development of leavened bread can probably also be traced to prehistoric times.
Fresh bread is prized for its taste, aroma, quality and texture. Retaining its freshness is important to keep it appetizing. Bread that has stiffened or dried past its prime is said to be stale. Modern bread is sometimes wrapped in paper or plastic film, or stored in a container such as a breadbox to keep it fresh longer. Bread that is kept in warm, moist environments is prone to the growth of mold. Bread kept at low temperatures, for example, in a refrigerator, will develop mold growth more slowly than bread kept at room temperature. However, unwrapped bread kept in a typical household refrigerator will turn stale quickly due to the low humidity of the air.
The soft, inner part of bread is known to bakers and other culinary professionals as the crumb, which is not to be confused with small bits of bread that often fall off, called crumbs. The outer hard portion of bread is called the crust.
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Etymology
The word itself, Old English bread, is common in various forms to many Germanic languages; such as Frisian brea, Dutch brood, German Brot, Swedish bröd, Norwegian and Danish brød; it has been claimed to be derived from the root of brew. However, it may be connected with the root of break, for its early uses are confined to broken pieces, or bits of bread, the Latin crustum, and it was not until the 12th century that it took the place—as the generic name for bread—of hlaf (hlaifs in Gothic: modern English loaf), which appears to be the oldest Teutonic name; Old High German hleib and modern German Laib, or Finnish leipä, Estonian leib, and Russian хлеб (khleb) are similar (all are derived from the Old German word for "loaf").
History
Bread is one of the oldest prepared foods, dating back to the Neolithic era. The first bread produced was probably cooked versions of a grain-paste, made from ground cereal grains and water, and may have been developed by accidental cooking or deliberate experimentation with water and grain flour. Descendants of this early bread are still commonly made from various grains in many parts of the world, including the Iranian (Persian) lavashs, taboons, sangaks, Mexican tortilla, Indian chapatis, rotis and naans, Scottish oatcake, North American johnnycake, Middle Eastern pita, and Ethiopian injera. Flat bread of these types also formed a staple in the diet of many early civilizations with the Sumerians eating a type of barley flat cake, and the 12th century BC Egyptians being able to purchase a flat bread called ta from stalls in the village streets.[2]
The development of leavened bread can probably also be traced to prehistoric times. Yeast spores occur everywhere, including the surface of cereal grains, so any dough left to rest will become naturally leavened. Although leavening is likely of prehistoric origin, the earliest archaeological evidence is from ancient Egypt. Scanning electron microscopy has detected yeast cells in some ancient Egyptian loaves. However, ancient Egyptian bread was made from emmer wheat and has a dense crumb. In cases where yeast cells are not visible, it is difficult, by visual examination, to determine whether the bread was leavened. As a result, the extent to which bread was leavened in ancient Egypt remains uncertain.[3]
There were multiple sources of leavening available for early bread. Airborne yeasts could be harnessed by leaving uncooked dough exposed to air for some time before cooking. Pliny the Elder reported that the Gauls and Iberians used the foam skimmed from beer to produce "a lighter kind of bread than other peoples." Parts of the ancient world that drank wine instead of beer used a paste composed of grape juice and flour that was allowed to begin fermenting, or wheat bran steeped in wine, as a source for yeast. The most common source of leavening however was to retain a piece of dough from the previous day to utilize as a form of sourdough starter.[4]
Even within antiquity there were a wide variety of breads. In the Deipnosophistae, the Greek author Athenaeus describes some of the bread, cakes, cookies, and pastries available in the Classical world. Among the breads mentioned are griddle cakes, honey-and-oil bread, mushroom shaped loaves covered in poppy seeds, and the military specialty of rolls baked on a spit. The type and quality of flours used to produce bread could also vary, as noted by Diphilus when he declared "bread made of wheat, as compared with that made of barley, is more nourishing, more digestible, and in every way superior." In order of merit, the bread made from refined [thoroughly sieved] flour comes first, after that bread from ordinary wheat, and then the unbolted, made of flour that has not been sifted."[5]
Within medieval Europe, bread served not only as a staple food but also as part of the table service. In the standard table setting of the day the trencher, a piece of stale bread roughly 6 by 4 inches (15 cm × 10 cm), served as an absorbent plate. At the completion of a meal the trencher could then be eaten, given to the poor, or fed to the dogs. It was not until the fifteenth century that trenchers made of wood started to replace the bread variety.[6]
Otto Frederick Rohwedder is considered to be the father of sliced bread. In 1912 Rohwedder started work on inventing a machine that sliced bread, but bakeries were reluctant to use it since they were concerned the sliced bread would go stale. It was not until 1928, when Rohwedder invented a machine that both sliced and wrapped the bread, that sliced bread caught on. A bakery in Chillicothe, Missouri was the first to use this machine to produce sliced bread.
For generations, white bread was the preferred bread of the rich while the poor ate dark (whole grain) bread. However, in most western societies, the connotations reversed in the late 20th century with whole grain bread becoming preferred as having superior nutritional value while white bread became associated with lower-class ignorance of nutrition.[citation needed]
Another major advance happened in 1961 with the development of the Chorleywood Bread Process which used the intense mechanical working of dough to dramatically reduce the fermentation period and the time taken to produce a loaf. The process, whose high-energy mixing allows for the use of inferior grain, is now widely used around the world in large factories.
More recently, and especially in smaller retail bakeries, chemical additives are used that both speed up mixing time and reduce necessary fermentation time, so that a batch of bread may be mixed, made up, risen, and baked in less than 3 hours. Dough that does not require fermentation because of chemical additives is called "no-time bread" by commercial bakers. Common additives include reducing agents such as L-cysteine or sodium metabisulfite, and oxidants such as potassium bromate or ascorbic acid.[7] Often these chemicals are added to dough in the form of a prepackaged base, which also contains most or all of the dough's non-flour ingredients. Using such bases and sophisticated chemistry, it has been possible for commercial bakers to make imitations of artisan and sourdough breads, traditionally made by semi-skilled labor working in smaller shops.
Recently, domestic breadmakers that automate the process of making bread have become popular in the home.
Cultural and political importance of bread
As a foodstuff of great historical and contemporary importance, in many cultures in the West and Near and Middle East bread has a significance beyond mere nutrition. The Lord's Prayer, for example, contains the line 'Give us today our daily bread'; here, 'bread' is commonly understood to mean necessities in general. The Roman poet Juvenal satirised superficial politicians and the public as caring only for "bread and circuses". In Israel the most usual phrase in work related demonstrations is "lekhem, avoda" [bread, work], and during the 1950s, the beatnik community used the term bread as a euphemism for money. In Cockney Rhyming Slang, bread means money and is derived from the phrase bread and honey.[8] The word bread is now commonly used around the world in English speaking countries as a synonym for money (as also is the case with the word dough.) The cultural importance of 'bread' goes beyond slang, however, to serve as a metaphor for basic necessities and living conditions in general. A 'bread-winner' is a household's main economic contributor and has little to do with actual bread-provision, for example. This also goes along with the phrase "putting bread on the table." A remarkable or revolutionary innovation is often referred to as "the greatest thing since sliced bread." In the USSR in 1917, Lenin and his fellow Bolsheviks promised "Peace, Land, and Bread."[9][10] In Newfoundland, bread was seen as having the power to protect against fairies. The term "breadbasket" is often used to denote an agriculturally productive region. In Slavic cultures bread and salt is offered as a welcome to all guests. In India, life's basic necessities are often referred to as "roti, kapra aur makan" [bread, cloth and house].
The political significance of bread is considerable. In Britain in the nineteenth century the inflated price of bread due to the Corn Laws caused major political and social divisions, and was central to debates over free trade and protectionism. The Assize of Bread and Ale in the thirteenth century showed the importance of bread in medieval times by setting heavy punishments for short-changing bakers, and bread appeared in Magna Carta a half-century earlier.
Types
Bread is a popular food in most societies. East Asian societies typically prefer wheat noodles, steamed bread, or rice. Bread is often made from a wheat-flour dough that is cultured with yeast, allowed to rise, and finally baked in an oval. Owing to its high levels of gluten (which give the dough sponginess and elasticity), common wheat (also known as bread wheat) is the most common grain used for the preparation of bread, but bread is also made from the flour of other wheat species (including durum, spelt and emmer), rye, barley, maize (or corn), and oats, usually, but not always, in combination with wheat flour. Although common wheat is best suited for making highly-risen white bread, other wheat species are capable of giving good black bread. Spelt bread (Dinkelbrot) continues to be widely consumed in Germany, and emmer bread was a staple food in ancient Egypt. Canadian bread is known for its heartier consistency due to high protein levels in Canadian flour.
- White bread is made from flour containing only the central core of the grain (endosperm).
- Brown bread is made with endosperm and 10% bran. It can also refer to white bread with added colouring (often caramel colouring) to make it 'brown'; commonly labeled in America as "Wheat" bread (as opposed to "Whole Wheat" bread.)[11]
- Wholemeal bread contains the whole of the wheat grain (endosperm and bran). It is also referred to as 'whole grain' or 'whole wheat' bread, especially in North America.
- Wheat germ bread has added wheat germ for flavoring.
- Whole grain bread can refer to the same as 'wholemeal bread', or to white bread with added whole grains to increase its fibre content (i.e. as in "60% whole grain bread").
- Roti is a whole wheat based bread eaten in South Asia. Naan is also a variant of Roti.
- Granary bread is bread made from granary flour. Trademarked to Hovis, it is made from malted white or brown flour, wheat germ and whole grains.
- Rye bread is made with flour from rye grain of variable levels. It is higher in fiber than many common types of bread and is often darker in color and stronger in flavor. In Scandinavia, Germany, Finland, the Baltic States, and Russia, rye is a popular type of bread.
- Unleavened Bread used For the Jewish feast of passover, does not include yeast, thus it does not rise.
Quick breads
Quick breads usually refer to breads chemically leavened, usually with both baking powder and baking soda, and a balance of acidic ingredients, and alkaline ingredients. Examples include: pancakes, waffles, muffins, and Boston brown bread.
Composition and chemistry
Formulation
The amount of flour is the most significant measurement in a bread recipe, as it affects texture and crumb the most. Professional bakers use a system of percentages known as Bakers' Percentage in their recipe formulations, and measure ingredients by weight instead of by volume. Measurement by weight is much more accurate and consistent than measurement by volume, especially for the dry ingredients.
Flour is always stated as 100%, and the rest of the ingredients are a percent of that amount by weight. Common table bread in the U.S. uses approximately 50% water, resulting in a finely-textured, light, bread. Most artisan bread formulas contain anywhere from 60 to 75% water. In yeast breads, the higher water percentages result in more CO2 bubbles, and a coarser bread crumb. One pound (~ 450 g) of flour will yield a standard loaf of bread, or two French loaves.
Calcium propionate is commonly added by commercial bakeries to retard the growth of molds.
Flour
Flour is a product made from grain that has been ground into a powdery consistency. It is flour that provides the primary structure to the final baked bread. Commonly available flours are made from rye, barley, maize, and other grains, but it is wheat flour that is most commonly used for breads. Each of these grains provides the starch and protein necessary for the production of bread.
The quantity of the proteins contained in the flour serve as the best indicator of the quality of the bread dough and the finished bread. While bread can be made from all-purpose wheat flour, for quality bread a specialty bread flour, containing more protein, is recommended. If one uses a flour with a lower (9-11%) protein content to produce bread, a longer mixing time will be required to develop gluten strength properly. This extended mixing time leads to oxidization of the dough, which gives the finished product a whiter crumb, instead of the cream color preferred by most artisan bakers.
Wheat flour in addition to its starch contains three water-soluble protein groups, albumin, globulin, proteoses, and two non-water soluble protein groups, glutenin and gliadin. When flour is mixed with water the water-soluble proteins dissolve, leaving the glutenin and gliadin to form the structure of the resulting dough. When worked by kneading, the glutenin forms strands of long thin chainlike molecules while the shorter gliadin forms bridges between the strands of glutenin. The resulting networks of strands produced by these two proteins are known as gluten. Gluten development improves if the dough is allowed to autolyse.
Liquids
Water, or some other liquid, is used to form the flour into a paste or dough. The volume of liquid required varies between recipes, but a ratio of 1 part liquid to 3 parts flour is common for yeast breads while recipes that use steam as the primary leavening method may have a liquid content in excess of one part liquid to one part flour by volume. In addition to water, other types of liquids that may be used include dairy products, fruit juices, or beer. In addition to the water in each of these they also bring additional sweeteners, fats, and/or leavening components.
Leavening
Leavening is the process of adding gas to a dough before or during baking to produce a lighter, more easily chewed bread. Most bread consumed in the West is leavened. However, unleavened breads have symbolic importance in Judaism and Christianity. Jews consume unleavened bread called Matza during Passover. They are also used in the Roman Catholic Christian liturgy when they celebrate the Eucharist, a rite derived from the narrative of the Last Supper when Jesus broke bread with his disciples, perhaps during a Passover Seder. On the other hand, the Orthodox Church always uses leavened bread.
Chemical leavening
A simple technique for leavening bread is the use of gas-producing chemicals. There are two common methods. The first is to use baking powder or a self-rising flour that includes baking powder. The second is to have an acidic ingredient such as buttermilk and add baking soda. The reaction of the acid with the soda produces gas.
Chemically-leavened breads are called quick breads and soda breads. This technique is commonly used to make muffins, pancakes, American-style biscuits and sweet breads such as banana bread.
Yeast leavening
Many breads are leavened by yeast. The yeast used for leavening bread is Saccharomyces cerevisiae, the same species used for brewing alcoholic beverages. This yeast ferments carbohydrates in the flour, including any sugar, producing carbon dioxide. Most bakers in the U.S. leaven their dough with commercially produced baker's yeast. Baker's yeast has the advantage of producing uniform, quick, and reliable results, because it is obtained from a pure culture. Many artisan bakers produce their own yeast by preparing a 'growth culture' which they then use in the making of bread. This culture kept in the right conditions will continue to grow and provide leavening for many years.
Both the baker's yeast and the sourdough method of baking bread follow the same pattern. Water is mixed with flour, salt and the leavening agent (baker's yeast or sourdough starter). Other additions (spices, herbs, fats, seeds, fruit, etc.) are not necessary to bake bread, but often used. The mixed dough is then allowed to rise one or more times (a longer rising time results in more flavor, so bakers often punch down the dough and let it rise again), then loaves are formed and (after an optional final rising time) the bread is baked in an oven.
Many breads are made from a straight dough, which means that all of the ingredients are combined in one step, and the dough baked after the rising time. Alternatively, dough can be made using a pre-ferment, when some of the flour, water, and the leavening are combined a day or so ahead of baking, and allowed to ferment overnight. On the day of the baking, the rest of the ingredients are added, and the rest of the process is the same as that for straight dough. This produces a more flavorful bread with better texture. Many bakers see the starter method as a compromise between the highly reliable results of baker's yeast, and the flavor/complexity of a longer fermentation. It also allows the baker to use only a minimal amount of baker's yeast, which was scarce and expensive when it first became available. Most yeasted preferments fall into one of three categories: poolish or pouliche, a loose-textured mixture composed of roughly equal amounts of flour and water (by weight); biga a stiff mixture with a higher proportion of flour; and pâte fermentée, which is simply a portion of dough reserved from a previous batch. Sourdough (also known as levain or "natural leaven") takes it a step further, creating a pre-ferment with flour and water that propagates naturally occurring yeast and bacteria (usually Saccharomyces exiguus, which is more acid-tolerant than S. cerevisiae, and various species of Lactobacillus.)
Sourdough
The sour taste of sourdoughs actually comes not from the yeast, but from a lactobacillus, with which the yeast lives in symbiosis. The lactobacillus feeds on the byproducts of the yeast fermentation, and in turn makes the culture go sour by excreting lactic acid, which protects it from spoiling (since most microbes are unable to survive in an acid environment). All yeast-leavened breads used to be sourdoughs, and the leavening process was not understood until the 19th century, when with the advance of microscopes, scientists were able to discover the microbes that make the dough rise. Since then, strains of yeast have been selected and cultured mainly for reliability and quickness of fermentation. Billions of cells of these strains are then packaged and marketed as "Baker's Yeast". Bread made with baker's yeast is not sour because of the absence of the lactobacillus. Bakers around the world quickly embraced baker's yeast for it made baking simple and so allowed for more flexibility in the bakery's operations. It made baking quick as well, allowing bakeries to make fresh bread from scratch as often as three times a day. While European bakeries kept producing sourdough breads, in the U.S., sourdough baking was widely replaced by baker's yeast, and only recently has that country (or parts of it, at least) seen the rebirth of sourdough in artisan bakeries. According to Alton Brown, host of Food Network's "Good Eats" television show, each region of the world has different strains of lactobacillus, hence the flavor of the bread made from home starters is unique. The San Francisco Bay Area is especially famous for its sourdough breads.
Sourdough breads are most often made with a sourdough starter (not to be confused with the starter method discussed above). A sourdough starter is a culture of yeast and lactobacillus. It is essentially a dough-like or pancake-like flour/water mixture in which the yeast and lactobacilli live. A starter can be maintained indefinitely by periodically discarding a part of it and refreshing it by adding fresh flour and water. (When refrigerated, a starter can go weeks without needing to be fed.) There are starters owned by bakeries and families that are several human generations old, much revered for creating a special taste or texture. Starters can be obtained by taking a piece of another starter and growing it, or they can be made from scratch. There are hobbyist groups on the web who will send their starter for a stamped, self-addressed envelope, and there are even mailorder companies that sell different starters from all over the world. An acquired starter has the advantage to be more proven and established (stable and reliable, resisting spoiling and behaving predictably) than from-scratch starters.
There are other ways of sourdough baking and culture maintenance. A more traditional one is the process that was followed by peasant families throughout Europe in past centuries. The family (usually the woman was in charge of breadmaking) would bake on a fixed schedule, perhaps once a week. The starter was saved from the previous week's dough. The starter was mixed with the new ingredients, the dough was left to rise, then a piece of it was saved (to be the starter for next week's bread). The rest was formed into loaves which were marked with the family sign (this is where today's decorative slashing of bread loaves originates from), and taken to the communal oven to bake. These communal ovens over time evolved into what are known today as bakeries, when certain people specialized in bread baking, and with time enhanced the process so far as to be able to mass produce cheap bread for everyone in the world.
Steam leavening
The rapid expansion of steam produced during baking leavens the bread, which is as simple as it is unpredictable. The best known steam-leavened bread is the popover. Steam-leavening is unpredictable since the steam is not produced until the bread is baked.
Steam leavening happens regardless of the rising agents (baking soda, yeast, baking powder, sour dough, beaten egg whites, etc.)
- The leavening agent either contains air bubbles or generates carbon dioxide.
- The heat vaporises the water from the inner surface of the bubbles within the dough.
- The steam expands and makes the bread rise.
It is actually the main factor in the rise of bread once it has been put in the oven. CO2 generation, on its own, is too small to account for the rise. Heat kills bacteria or yeast at an early stage, so the CO2 generation is stopped.
Bacterial leavening
Salt rising bread employs a form of bacterial leavening that does not require yeast. Although the leavening action is not always consistent, and requires close attention to the incubating conditions, this bread is making a comeback due to its unique cheese-like flavor and fine texture.[12]
Aeration
Aerated bread is leavened by carbon dioxide being forced into dough under pressure. The technique is no longer in common use, but from the mid 19th to 20th centuries bread made this way was somewhat popular in the United Kingdom, made by the Aerated Bread Company and sold in its high-street tearooms.
Fats or shortenings
Fats such as butter, vegetable oils, lard, or that contained in eggs affects the development of gluten in breads by coating and lubricating the ind