Bread starter
Encyclopedia
A pre-ferment is a fermentation starter
used in bread
making, and is referred to as an indirect 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.
, 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.) 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:
, water
, and a leavening agent (typically yeast
). It often lacks both salt and granulated sugar, each of which act to inhibit yeast growth, 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.
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. 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
. This time may be extended through refrigeration
. Sourdough starters minimally take several days, and are subject to many variables.
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.
Fermentation starter
Fermentation starters are preparations to assist the beginning of the fermentation process in preparation of various foods and fermented drinks. A starter culture is a microbiological culture which actually performs fermentation...
used in bread
Bread
Bread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...
making, and is referred to as an indirect 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: spongesSponge and dough
The sponge and dough method is a two-step bread making process: in the first step a sponge is made and allowed to ferment for a period of time, and in the second step the sponge is added to the rest of the ingredients; this is known as the final dough. In this usage, synonyms for sponge are yeast...
, based on baker's yeast
Baker's yeast
Baker's yeast is the common name for the strains of yeast commonly used as a leavening agent in baking bread and bakery products, where it converts the fermentable sugars present in the dough into carbon dioxide and ethanol...
, and the starters of sourdough
Sourdough
Sourdough is a dough containing a Lactobacillus culture, usually in symbiotic combination with yeasts. It is one of two principal means of biological leavening in bread baking, along with the use of cultivated forms of yeast . It is of particular importance in baking rye-based breads, where yeast...
, based on wild yeasts and lactic-acid bacteria. (Some bakers, however, use the term to refer only to the yeast variety.) 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:
- BigaBiga (bread baking)Biga is a type of pre-ferment used in Italian baking. Many popular Italian breads, including ciabatta, are made using a biga. Using a biga adds complexity to the bread's flavour and is often used in breads which need a light, open texture with holes...
and poolish are terms used in Italian and French baking, respectively, for sponges made with domestic baker's yeastBaker's yeastBaker's yeast is the common name for the strains of yeast commonly used as a leavening agent in baking bread and bakery products, where it converts the fermentable sugars present in the dough into carbon dioxide and ethanol...
. 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. Bigas can be held longer at their peak than wetter sponges, while a poolish is one known technique to increase a dough's extensibility. - 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.
- SourdoughSourdoughSourdough is a dough containing a Lactobacillus culture, usually in symbiotic combination with yeasts. It is one of two principal means of biological leavening in bread baking, along with the use of cultivated forms of yeast . It is of particular importance in baking rye-based breads, where yeast...
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, lactobacillusLactobacillusLactobacillus is a genus of Gram-positive facultative anaerobic or microaerophilic rod-shaped bacteria. They are a major part of the lactic acid bacteria group, named as such because most of its members convert lactose and other sugars to lactic acid. They are common and usually benign...
, and acetobacteria. They are often maintained over long periods of time. The Boudin BakeryBoudin BakeryBoudin Bakery is a bakery based in San Francisco, California, known for its sourdough bread...
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; however, mother dough may also refer to a yeast pre-ferment; so the process 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 ChefChef (baking)A chef is type of bread starter. It is a piece of dough taken from a previous batch used to inoculate a new dough with yeasts and Lactobacilli. The term chef is French. It may also be called chief or head....
.
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. 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 flourWheat flour
Wheat flour is a powder made from the grinding of wheat used for human consumption. More wheat flour is produced than any other flour. Wheat varieties are called "clean," "white," or "brown" if they have high gluten content, and they are called "soft" or "weak" flour if gluten content is low...
, water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, and a leavening agent (typically yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
). It often lacks both salt and granulated sugar, each of which act to inhibit yeast growth, as well as fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
. After mixing it is allowed to ferment for a period of time, and then is added to bread dough
Dough
Dough is a paste made out of any cereals or leguminous crops by mixing flour with a small amount of water and/or other liquid. This process is a precursor to making a wide variety of foodstuffs, particularly breads and bread-based items , flatbreads, noodles, pastry, and similar items)...
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.
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. 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
Baker percentage
Baker's percentage is a baker's notation method indicating the flour-relative proportion of ingredients used when making breads, cakes, muffins, and other pastries. It is also referred to as baker's math, or otherwise contextually indicated by a phrase such as based on flour weight...
. This time may be extended through refrigeration
Refrigeration
Refrigeration is a process in which work is done to move heat from one location to another. This work is traditionally done by mechanical work, but can also be done by magnetism, laser or other means...
. Sourdough starters minimally take several days, and are subject to many variables.
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.