Leavening agent
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In cooking, a leavening agent (/ˈlɛvənɪŋ/) or raising agent, also called a leaven (/ˈlɛvən/) or leavener, is any one of a number of substances used in doughs and batters that cause a foaming action (gas bubbles) that lightens and softens the mixture. An alternative or supplement to leavening agents is mechanical action by which air is incorporated (i.e. kneading). Leavening agents can be biological or synthetic chemical compounds. The gas produced is often carbon dioxide, or occasionally hydrogen.[1]
When a dough or batter is mixed, the
and sets, leaving gas bubbles that remain.Biological leavening agents
- Saccharomyces cerevisiae producing carbon dioxide found in:
- baker's yeast
- Beer barm(unpasteurised—live yeast)
- ginger beer
- kefir
- sourdough starter
- Clostridium perfringens producing hydrogen found in salt-rising bread
Chemical leavening agents
Chemical leavens are mixtures or compounds that release gases when they react with each other, with moisture, or with heat. Most are based on a combination of acid (usually a low molecular weight organic acid) and a
History
Chemical leavening using
Since chemical expertise is required to create a functional chemical leaven without producing off-flavors from the chemical precursors involved, such substances are often mixed into premeasured combinations for maximum results. These are generally referred to as
Other leavens
Mechanical leavening
Using a whisk on certain liquids, notably cream or egg whites, can also create foams through mechanical action. This is the method employed in the making of sponge cakes, where an egg protein matrix produced by vigorous whipping provides almost all the structure of the finished product.
The Chorleywood bread process uses a mix of biological and mechanical leavening to produce bread; while it is considered by food processors[who?] to be an effective way to deal with the soft wheat flours characteristic of British Isles agriculture, it is controversial[according to whom?] due to a perceived lack of quality in the final product. The process has nevertheless been adapted by industrial bakers in other parts of the world.
See also
- Aerated Bread Company, bakeries started in 1862 in the UK that made carbon dioxide leavened bread
- Baking powder
- Chametz
- Parable of the Leaven
- Passover
- Unleavened bread
References
- ^ Jacobs, Morris Boris (1951). The Chemistry and Technology of Food and Food Products. Hoboken, NJ: Interscience Publishers. p. 1932.
- ISBN 978-3-527-33512-1.
- ISBN 0-486-24710-4.
- ISBN 978-0-19-988576-3.
- ISBN 0-8493-8980-1.
Further reading
- Matz, S (1972). "Bakery Technology and Engineering", AVI Publishing Co.
External links
- Wikibooks Cookbook has a recipe/module on Leavening agent