A
pre-ferment (pâte fermentée), also called a
sponge, a
starter, or the
mother dough is a
fermentation starterFermentation 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
breadBread 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 , but in some cuisines breads are steamed, fried, or baked on a hot skillet. It may be leavened or unleavened...
bakingBaking is the technique of prolonged cooking of food by dry heat acting by convection, and not by radiation, normally in an oven, but also in hot ashes, or on hot stones. It is primarily used for the preparation of bread, cakes, pastries and pies, tarts, quiches, and cookies. Such items are...
. It usually consists of a simple mixture of
flourFlour is a powder made of cereal grains or roots. It is the main ingredient of bread, which is a staple food for many civilizations, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...
,
waterWater is an ubiquitous chemical substance that is composed of hydrogen and oxygen and is essential for all known forms of life.In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71%...
, and a leavening agent (typically
yeastYeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with about 1,500 species currently described; they dominate fungal diversity in the oceans. Most reproduce asexually by budding, although a few do so by binary fission...
), and is added to bread dough before the
kneadingKneading is a process in the making of bread, used to mix together the ingredients and add strength to the bread. Its importance lies in the mixing of flour with water. When these two ingredients are combined and kneaded, the gliadin and glutenin proteins in the flour expand and form strands of...
and baking process as a substitute for yeast. Though they 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.
Using a pre-ferment and a longer fermentation in the breadmaking process gives greater complexity of flavor, through yeast- and bacterial-action, enhancing the flavour and keeping time of the finished product. The starter ingredients are mixed in a container at least three times bigger than the ingredients, to allow room for the starter to grow. The starter is left sitting at room temperature, up to 72 hours, before being added to the dough. Starters typically last three to five days, but this time can be extended through
refrigerationRefrigeration is the process of removing heat from an enclosed space, or from a substance, and moving it to a place where it is unobjectionable. The primary purpose of refrigeration is lowering the temperature of the enclosed space or substance and then maintaining that lower temperature.The term...
and providing more water and flour until it is ready to be used.
There are several kinds of pre-ferment commonly used in bread baking:
- Sourdough
Sourdough is a dough containing a lactobacillus culture, usually in symbiotic combination with yeasts. It is one of two principal means of 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 does not...
starter is likely the oldest, being entirely reliant on wild yeasts present in the grain and local environment. Sourdough starters are maintained over long periods of time. The Boudin BakeryThe Boudin Bakery is a bakery situated in San Francisco, California known for its sourdough bread...
in San Francisco for example, has used the same starter dough for over 150 years. These starters generally have fairly complex microbiological makeups, most notably including wild yeasts, lactobacillusLactobacillus is a genus of Gram-positive facultative anaerobic or microaerophilic 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. A roughly synonymous term in French baking is levainLevain is a bread leavening agent used traditionally in France and today by artisan bakeries and hobbyists around the world. It produces breads with rich aroma, pleasant structure and excellent keeping properties. Levain is a type of pre-ferment which is made in two fermentation steps from an...
.
- Old dough (pâte fermentée) sponges can be made with any sort of yeast, and essentially consist of a piece of dough reserved from a previous batch of bread, with more flour and water added in to feed the remaining yeast.
- Biga
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 flavor 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 starters made with domestic baker's yeastBaker's yeast is the common name for the strains of yeast commonly used as a leavening agent in baking bread and related products, where it converts the fermentable sugars present in the dough into carbon dioxide and ethanol. The use of potatoes, water from potato boiling, eggs, or sugar in a bread...
. Poolish is usually a fairly wet starter (typically made with a one-part-flour-to-one-part-water ratio by weight), while biga can be wet or dry. Poolish was first used by Polish bakers around 1840, hence its name, and as a method was brought to France in the beginning of 1920s.