Editing Flour (section)

== Composition ==
[[File:Uskladněná mouka.JPG|thumb|Flour being stored in large cloth [[flour sack|sacks]]]]
Flour contains a high proportion of [[starch]]es, which are a subset of complex [[carbohydrate]]s also known as [[polysaccharide]]s. The kinds of flour used in cooking include all-purpose flour (known as plain outside North America), self-rising flour, and cake flour (including bleached flour). The higher the protein content the harder and stronger the flour, and the more it will produce crispy or chewy breads. The lower the protein the softer the flour, which is better for cakes, cookies, and pie crusts.<ref>{{Cite news|url=http://www.buzzle.com/articles/self-rising-flour-vs-all-purpose-flour.html|title=Self-rising Flour Vs. All-purpose Flour: Know the Difference|work=Tastessence|access-date=2011-04-15|language=en-US|archive-date=2013-01-19|archive-url=https://archive.today/20130119001316/http://www.buzzle.com/articles/self-rising-flour-vs-all-purpose-flour.html|url-status=usurped}}</ref> Cereal flour consists either of the [[endosperm]], [[cereal germ|germ]], and [[bran]] together (whole-grain flour) or of the endosperm alone (refined flour).

=== Bleached flour ===

"Bleached flour" is "refined" flour with a [[flour bleaching agent|chemical whitening (bleaching) agent]] added.  "Refined" flour has had the germ and bran, containing much of the nutritional fibre and vitamins, removed and is often referred to as "white flour".

Bleached flour is artificially aged using a "bleaching" agent, a "maturing" agent, or both. A bleaching agent affects the carotenoids responsible for the natural colour of the flour; a "maturing" agent also affects [[gluten]] development. A maturing agent may either strengthen or weaken gluten development.

==== Additives ====
The four most common additives used as bleaching/maturing agents in the US are:
* [[Potassium bromate]], listed as an ingredient, is a maturing agent that strengthens gluten development. It does not bleach.
* [[Benzoyl peroxide]] bleaches, but does not act as a maturing agent. It has no effect on gluten.
* [[Ascorbic acid]] (vitamin C) is listed as an ingredient, either as an indication that the flour was matured using ascorbic acid or that a small amount is added as a dough enhancer. It is a maturing agent that strengthens gluten development, but does not bleach.
* [[Chlorine]] gas is used as both a bleaching agent and a maturing agent. It weakens gluten development and oxidizes starches, making it easier for the flour to absorb water and swell, resulting in thicker batters and stiffer doughs. The retarded gluten formation is desirable in cakes, cookies, and biscuits, as it would otherwise make them tougher and bread-like. 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.<ref>{{Cite book| last1 = Figoni| first1 = Paula I. | title = How baking works | publisher = John Wiley & Sons| year = 2010| page = 86| isbn = 978-0-470-39267-6| url = https://books.google.com/books?id=XqKF7PqV02cC}}</ref> Chlorinated flour allows cakes and other baked goods to set faster and rise better, and the fat to be distributed more evenly, with less vulnerability to collapse.

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.

Common preservatives in commercial flour include:
* [[Calcium propanoate]]
* [[Sodium benzoate]]
* [[Tricalcium phosphate]]
* [[Butylated hydroxyanisole]]

==== Frequency of additives ====

All bleaching and maturing agents (with the possible exception of ascorbic acid) have been banned in the United Kingdom.<ref>{{cite web|url= http://www.food.gov.uk/multimedia/pdfs/breadflourguide.pdf|title= The Bread and Flour Regulations 1998 – Guidance Notes|date= 1 June 2008|publisher= Food Standards Agency|access-date= 29 March 2012|archive-date= 9 December 2011|archive-url= https://web.archive.org/web/20111209193220/http://www.food.gov.uk/multimedia/pdfs/breadflourguide.pdf|url-status= live}}</ref>

Bromination of flour in the US 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 varieties of flour packaged specifically for commercial bakeries are still bromated. Retail bleached flour marketed to the home baker is now treated mostly with either peroxidation or chlorine gas. Current information from Pillsbury is that their varieties of bleached flour are treated both with benzoyl peroxide and chlorine gas. Gold Medal states that their bleached flour is treated either with benzoyl peroxide or chlorine gas, but no way exists to tell which process has been used when buying the flour at the grocery store.

====Old method of bleaching====
The old method of procuring white or "bleached" flour did not entail the use of chemical agents at all. Rather, the [[Wheat berry|wheat kernels]] were moistened with water long enough for the outer kernels of the wheat which contained the [[bran]] to soften and, eventually, fall off while grinding.<ref>[[Babylonian Talmud]] (''[[Pesachim]]'' 40a), Quote: "It is impossible to obtain a clean, white bread without moistening [the grain]" ({{langx|he|אי אפשר נקיה בלא לתיתה}}).</ref> In some places, the leaves of Syrian rue (''[[Peganum harmala]]'') were spread in stratified layers between the layers of grain, and left in such a state for several days, until the fumes emitted from the astringent leaves of the plant caused the outer kernels of the wheat to break down and dissolve, leaving a clean and white flour after grinding.<ref>{{cite book |last=Saleh|first=Y. |author-link=Yiḥyah Salaḥ |title=Questions & Responsa 'Pe'ulath Ṣadīq'|volume=1 |edition=2nd |date=1979 |location=Jerusalem |page=109 |language=he |oclc=122773689 }} ({{OCLC|122773689}}), ''responsum'' no. 171</ref><ref>{{cite book |last=Qafih |first=Y. |author-link=Yosef Qafih|title=Halichot Teman (Jewish Life in Sanà) |publisher=[[Ben-Zvi Institute]] |date=1982 |location=Jerusalem |page=15 |language=he |isbn=965-17-0137-4 |oclc=863513860 }}</ref><ref>{{Citation |contribution=Hil. Ḥametz u'matzah |title=Sefer Mishneh Torah |editor-last=Qafih |editor-first=Y. |editor-link=Yosef Qafih |edition=4 |volume=4 (Zemanim) |publisher=Mekhon mishnat ha-Rambam|place=Kiryat Ono|year=2011 |page=342 (note 14) |language=he |oclc=187478401 |title-link=Mishneh Torah}}, s.v. ''Ḥametz u'matzah'' 5:8</ref><ref>{{Citation |contribution=Scholars of Yemen Answer Questions of Rabbi A.I. Kook |title=Ascending the Palm Tree: An Anthology of the Yemenite Jewish Heritage|last=Gaimani|first=Aharon|editor1=Rachel Yedid|editor2=Danny Bar-Maoz|publisher=E'ele BeTamar|place=Rehovot|year=2018 |page=115 |oclc=1041776317 |isbn=978-965-7121-33-7}}</ref>

=== Enriched flour ===
{{Main|Enriched flour}}
During the process of making flour, specifically as a result of the bleaching process, nutrients are lost. Some of these nutrients may be replaced during refining – the result is known as ''enriched'' flour. In the UK most flour, and consequently breads made with it, is required to be fortified with added calcium, iron, thiamine (Vitamin B1) and niacin (Vitamin B3); wholemeal flour is exempt as it inherently contains sufficient of these nutrients.<ref>{{cite web | title=Bread and Flour Regulations | publisher=UK Flour Millers | date=October 2023| url=https://www.ukflourmillers.org/bread-and-flour-regulations}}</ref>

=== Cake flour ===
Cake flour is the lowest in gluten protein content, with 6–7%<ref name="Reinhart-2001">{{Cite book|title=The Bread Baker's Apprentice|last=Reinhart|first=Peter|publisher=Ten Speed Press|year=2001|isbn=978-158008-268-6|location=Berkeley, California|page=29}}</ref> (5–8% from second source<ref name="Food Network-2018">{{cite web|url=http://www.foodnetwork.com/recipes/packages/baking-guide/flour-101-guide-to-different-types-and-uses|title=Different Flour Types|website=Food Network|access-date=2018-01-04|archive-date=2018-01-05|archive-url=https://web.archive.org/web/20180105123050/http://www.foodnetwork.com/recipes/packages/baking-guide/flour-101-guide-to-different-types-and-uses|url-status=live}}</ref>) protein to produce minimal binding so the cake "crumbles" easily.

=== Pastry flour ===
Pastry flour has the second-lowest gluten protein content, with 7.5–9.5%<ref name="Reinhart-2001" /> (8–9% from second source<ref name="Food Network-2018" />) protein to hold together with a bit more strength than cakes, but still produce flaky crusts rather than hard or crispy ones.

=== Plain or all-purpose flour ===
All-purpose, or "AP flour", or plain flour is medium in gluten protein content at 9.5–11.5%<ref name="Reinhart-2001" /> (10–12% from second source<ref name="Food Network-2018" />) protein content.  It has adequate protein content for many bread and pizza bases, though bread flour and special 00 grade Italian flour are often preferred for these purposes, respectively, especially by artisan bakers. Some biscuits are also prepared using this type of flour. "Plain" refers not only to AP flour's middling gluten content but also to its lack of any added leavening agent (as in self-rising flour).

=== Bread flour ===
Bread flour is typically made from [[hard red winter wheat]] planted in the fall and harvested in the spring. Hard wheat is high in gluten, a protein that makes dough stretchy. Hard wheat is 11.5–13.5%<ref name="Reinhart-2001" /> (12–14% from second source<ref name="Food Network-2018" />) protein. The increased protein binds to the flour to entrap [[carbon dioxide]] released by the yeast [[fermentation (food)|fermentation]] process, resulting in a better rise and chewier texture.

=== Hard flour ===
Hard is a general term for flours with high gluten protein content, commonly refers to extra strong flour, with 13.5–16%<ref name="Reinhart-2001" /> (or 14–15% from some sources) protein (16% is a theoretically possible protein content<ref name="Reinhart-2001" />).  This flour may be used where a recipe adds ingredients that require the dough to be extra strong to hold together in their presence, or when strength is needed for constructions of bread (e.g., some centerpiece displays).

=== Gluten flour ===
Gluten flour is refined gluten protein, or a theoretical 100% protein (though practical refining never achieves a full 100%). It is used to strengthen flour as needed.  For example, adding approximately one teaspoon per cup of AP flour gives the resulting mix the protein content of bread flour.  It is commonly added to whole grain flour recipes to overcome the tendency of greater fiber content to interfere with gluten development, needed to give the bread better rising (gas holding) qualities and chew.

=== Unbleached flour ===
Unbleached flour is simply flour that has not undergone bleaching and therefore does not have the color of "white" flour. An example is [[graham flour]], whose namesake, [[Sylvester Graham]], was against using bleaching agents, which he considered unhealthy.

=== Self-raising flour ===
In English-speaking countries, self-raising (or self-rising) flour is commercially available with chemical [[leavening agent]]s already in the mix.<ref>[http://bakingbites.com/2007/08/what-is-self-rising-flour/ Self-rising flour] {{Webarchive|url=https://web.archive.org/web/20110616010925/http://bakingbites.com/2007/08/what-is-self-rising-flour/ |date=2011-06-16 }} -Retrieved 2011-04-15</ref><ref>[https://www.nigella.com/ask/self-rising-flour-substitution/ Nigella Lawson] {{Webarchive|url=https://web.archive.org/web/20210412195950/https://www.nigella.com/ask/self-rising-flour-substitution |date=2021-04-12 }} -Retrieved 2021-03-13</ref> In America, it is also likely to be pre-salted; in Britain this is not the case. The added ingredients are evenly distributed throughout the flour, which aids a consistent rise in baked goods. This flour is generally used for preparing sponge cakes, scones, muffins, etc. It was invented by [[Henry Jones (baker)|Henry Jones]] and patented in 1845. If a recipe calls for self-raising flour, and this is not available, the following substitution is possible:
* 1 cup (125 g) plain flour
* 1 teaspoon (3 g) [[baking powder]]
* (US recipes) a pinch to {{frac|1|4}} teaspoon (1 g or less) [[salt]]