Pre-ferment

Pain poolish - a pre-ferment

A pre-ferment is a fermentation starter used in bread making, and is referred to as an indirect^[1][2] method. It may also be called mother dough.

A pre-ferment and a longer fermentation in the bread-making process have several benefits: there is more time for yeast, enzyme and, if sourdough, bacterial actions on the starch and proteins in the dough; this in turn improves the keeping time of the baked bread, and it creates greater complexities of flavor. Though pre-ferments have declined in popularity as direct additions of yeast in bread recipes have streamlined the process on a commercial level, pre-ferments of various forms are widely used in artisanal bread recipes and formulas.

Classifications

Generally, there are two pre-ferment varieties: sponges, based on baker's yeast, and the starters of sourdough, based on wild yeasts and lactic-acid bacteria. (Some bakers, however, use the term to refer only to the yeast variety.^[3]) There are several kinds of pre-ferment commonly named and used in bread baking. They all fall on a varying process and time spectrum, from a mature mother dough of many generations of age to a first-generation sponge based on a fresh batch of baker's yeast:

• Biga and poolish are terms used in Italian and French baking, respectively, for sponges made with domestic baker's yeast. Poolish is a fairly wet sponge (typically made with a one-part-flour-to-one-part-water ratio by weight), while biga is usually drier.^[4] Bigas can be held longer at their peak than wetter sponges,^[5] while a poolish is one known technique to increase a dough's extensibility.^[6]
• Old dough (pâte fermentée) may be made with yeast or sourdough cultures, and essentially consists of a piece of dough reserved from a previous batch, with more flour and water added to feed the remaining flora. Because this is a piece of old dough, it has the typical ingredient of salt to distinguish it from other pre-ferments.^[7]
• Sourdough starter is likely the oldest, being reliant on organisms present in the grain and local environment. These starters generally have fairly complex microbiological makeups, most notably including wild yeasts, lactobacillus, and acetobacteria.^[8][9] They are often maintained over long periods of time. The Boudin Bakery in San Francisco for example, has used the same starter dough for over 150 years. A roughly synonymous term in French baking is levain.
• Mother dough often refers to a sourdough, and in this context the term starter often refers to all or a piece of mother dough;^[10] however, mother dough may also refer to a yeast pre-ferment;^[11] so the process^[12] used in relation to the ingredients and fermentation times is important to understanding yeast versus sourdough methods. A roughly synonymous term used in French baking is Chef.^[13]

History

The common, but undocumented, origin given for the term poolish is that it was first used by Polish bakers around 1840, hence its name, and as a method was brought to France in the beginning of the 1920s. "Poolish" however is an old English version of "Polish", whereas the term seems to be most used in France (where "polonais" is the word for "Polish"). More logically, some nineteenth century sources use the homonym "pouliche", a French word which typically means a female foal.^[14] With either spelling, the term only appears in French sources towards the last part of the nineteenth century. There is not currently any credible explanation for the origin of the term.

Use

A pre-ferment is easy to make and usually consists of a simple mixture of wheat flour, water, and a leavening agent (typically yeast). It often lacks both salt and granulated sugar, each of which act to inhibit yeast growth,^[15] as well as fat. After mixing it is allowed to ferment for a period of time, and then is added to bread dough as a substitute for, or in addition to more yeast. There are distinctly different brew types of pre-ferments designed for computer-controlled bakeries that use a rather different series of ingredients, including oxidizers, needed for continuous dough-production processes.^[16]

To allow room for the pre-ferment to rise, the ingredients are mixed in a container at least four or five times their volume. This is about the point in time when some process similarities of yeast pre-ferments to sourdough or levain starters begins to diverge.^[17] The typical amounts of time allotted for the yeast pre-ferment period may range from 2–16 hours, depending on the dough's temperature and the added amount of viable yeast, often expressed as a bakers' percentage.^[18] This time may be extended through refrigeration.^[19] Sourdough starters minimally take several days, and are subject to many variables.^[20]

To make a sourdough starter from scratch, all it takes is unbleached flour, dechlorinated water, and time, as well as daily feedings or refreshments of fresh flour and water. The starter is left sitting at room temperature for the desired time period before being added to the dough. To refresh the starter it is generally best advised to first reduce the amount of starter by half, unless you need to increase its weight, and replacing it with a 50-50 mix of flour and water. When expressed as a bakers' percentage, 50 parts of flour added to 50 parts of water is 100% hydration. Stiffer hydrations, such as 50% or 67-33, may also be used. When cooling a levain or sourdough pre-ferment, if the dough temperature drops below 10 °C (50 °F) it affects the culture and leads to the loss of a particular aroma in the baked bread.^[21]

References

1. ^ The Artisan. "Direct and Indirect Methods of Bread Baking". http://www.theartisan.net/Direct_Sponge_and_Biga.htm. Retrieved April 27, 2010. 
2. ^ Reinhart, Peter (2001). The bread baker's apprentice: mastering the art of extraordinary bread. Berkeley, Calif: Ten Speed Press. p. 51. ISBN 1-58008-268-8. 
3. ^ Griffin, Mary Annarose; Gisslen, Wayne (2005). Professional baking. New York: John Wiley. p. 84. ISBN 0-471-46427-9. 
4. ^ Griffin, Mary Annarose; Gisslen, Wayne (2005). Professional baking. New York: John Wiley. p. 85. ISBN 0-471-46427-9. 
5. ^ Rees, Nicole; Amendola, Joseph (2003). The baker's manual: 150 master formulas for baking. London: J. Wiley. p. 33. ISBN 0-471-40525-6. 
6. ^ Daniel T. DiMuzio (2009). Bread Baking: An Artisan's Perspective. New York: Wiley. p. 142. ISBN 0-470-13882-3. 
7. ^ Reinhart, Peter (1998). Crust & Crumb: Master Formulas For Serious Bakers. Berkeley, Calif: Ten Speed Press. p. 38. ISBN 1-58008-003-0. 
8. ^ Scheirlinck I, Van der Meulen R, Van Schoor A, et al. (April 2008). "Taxonomic structure and stability of the bacterial community in belgian sourdough ecosystems as assessed by culture and population fingerprinting". Appl. Environ. Microbiol. 74 (8): 2414–23. doi:10.1128/AEM.02771-07. PMC 2293155. PMID 18310426. http://aem.asm.org/cgi/pmidlookup?view=long&pmid=18310426. 
9. ^ Elke K. Arendt, Liam A.M. Ryana and Fabio Dal Belloa (2007). "Impact of sourdough on the texture of bread". Food Microbiology 24 (2): 165–174. doi:10.1016/j.fm.2006.07.011. PMID 17008161. 
10. ^ Arnold L. Demain; Reinhard Renneberg (2007). Biotechnology for Beginners. Boston: Academic Press. pp. 18–19. ISBN 0-12-373581-5. 
11. ^ Esposito, Mary Ann (2003). Ciao Italia in Tuscany: traditional recipes from one of Italy's most famous regions. New York: St. Martin's Press. p. 94. ISBN 0-312-32174-0. http://books.google.com/books?id=37_Lt9Ch7nwC&pg=PA94#v=onepage&q&f=false. Retrieved 2010 Aug 13. 
12. ^ Nanna A. Cross; Corke, Harold; Ingrid De Leyn; Nip, Wai-Kit (2006). Bakery products: science and technology. Oxford: Blackwell. p. 551. ISBN 0-8138-0187-7. 
13. ^ Calvel, Raymond (2001). The taste of bread. Gaithersburg, Md: Aspen Publishers. p. 90. ISBN 0-8342-1646-9. 
14. ^ Jean Augustin Barral (1892) (in French). Dictionnaire d'agriculture ... - Google Books. 4. p. 19. http://books.google.com/books?pg=PA19&dq=pouliche+boulangerie&lr=&as_drrb_is=b&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is=1915&cd=6&id=IBxEAAAAYAAJ&num=100&as_brr=0#v=onepage&q=pouliche%20boulangerie&f=false. 
15. ^ Young, Linda; Cauvain, Stanley P. (2007). Technology of Breadmaking. Berlin: Springer. p. 88. ISBN 0-387-38563-0. http://books.google.com/books?id=HXtJivmeDfcC&pg=PA88#v=onepage&q&f=false. Retrieved 2011 April 24. 
16. ^ Evers, A. D.; Kent, N. (1994). Technology of cereals: an introduction for students of food science and agriculture. New York: Pergamon Press. p. 202. ISBN 0-08-040834-6. 
17. ^ Gisslen, Wayne (2009). Professional baking. New York: John Wiley. pp. 131–138. ISBN 0-471-78349-8. 
18. ^ Gisslen, Wayne (2009). Professional baking. New York: John Wiley. p. 133. ISBN 0-471-78349-8. 
19. ^ Calvel, Raymond (2001). The taste of bread. Gaithersburg, Md: Aspen Publishers. p. 44. ISBN 0-8342-1646-9. 
20. ^ Gisslen, Wayne (2009). Professional baking. New York: John Wiley. p. 135. ISBN 0-471-78349-8. 
21. ^ Calvel, Raymond (2001). The taste of bread. Gaithersburg, Md: Aspen Publishers. p. 92. ISBN 0-8342-1646-9.