Pre-ferments

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Pre-fermented dough or batter, called Pre-ferments, are added to Sourdough, Artisan or Hearth Bread recipes, and provide part or all of the leavening, add flavor and unique textures, contribute to dough strength and improve shelf life. There are multiple types - Biga, Pâte fermentée, Poolish, Sponge and Sourdough. You will also hear names such as desem (Belgian), chef, seed culture, sourdough culture, madre bianca, mother, and starter. A Soaker is another type of pre-ferment which is non-yeasted.

Pre-ferments are ways of giving a "head start" to new dough. They are composed of a portion of the total recipe's ingredients, typically flour, water, and yeast, and infrequently salt, while others are made from simple mixtures of just flour and water, allowed to ferment under controlled conditions before mixing. They are described by the amount of water they contain as stiff or wet, and vary by fermentation times, temperatures, and other details of their making. Most pre-ferments, with the exception of Sourdough or Levain, use commercial yeast, as opposed to attracting wild yeast and bacteria. (Bread can be made with both a sourdough starter and commercial yeast, called levain de pâte or a mixed starter.)  

The mixture, after fermenting in your home kitchen for a controlled period of time and conditions, is then added to the bread recipe using specific mixing methods, or the indirect dough mixing method (versus the direct dough or straight dough method). The pre-fermented breads, other than those made with a Sourdough Starter, tend to have a mild-tasting tangy or wheaty flavor, and vary from a fine to large air-pocket (cell) and a unique crust. Sourdough bread tends to have more "sourness" or "wheatiness", a crustier crust, and a unique crumb with irregular air holes.

BIGA 
This is an Italian term that generically means pre-ferment (known as sour in English). It can be quite stiff (50 to 60% water based on flour weight) in texture, or it can be of loose consistency (100% hydration). It is simply a mini-dough made with flour, water, a small amount of yeast (the yeast can be as little as .1% of the biga flour weight), and no salt. Once mixed, it is given a long, cool fermentation (65 degrees F) for at least 6 hours, and for as much as 24 hours ahead and delivers ample acetic acid. It should be used within 3 days, otherwise it becomes too acidic, weakening the gluten and adding a very sour flavor. It was developed to bolster extremely weak Italian flour and is still used to strengthen dough via the acetic acid, and is particularly useful in ciabatta, with its high water content, to strengthen its gluten network.

PÂTE FERMENTÉE (OLD DOUGH, SCRAP DOUGH OR PRE-FERMENTED DOUGH)
It is a French term that means pre-fermented dough, or as it is occasionally called, simply old dough, scrap dough or pre fermented dough, invented by Professor Calvel, at ENSMIC in Paris, France. It is done by taking small piece of fermented dough saved from one made earlier in the day or from the previous day's batch and then, adding it to the very end of mixing to today's dough. The amount to be added may vary around 15% of the weight of the total formula flour, or sometimes a bit more. Then, a portion of today's newly mixed batch is held and fermented for the next day's dough. Professor Calvel notes that "taking dough from one batch and adding it to a subsequent batch cannot be done indefinitely, or even over generations, without the danger of producing undesirable flavors."

The old dough piece should have a minimum of 3 hours fermentation after having been leavened with 1.5% yeast (based on total flour weight). It can stay at room temperature for up to 12 - 14 hours or be refrigerated for up to 18 - 20 hours.

The concept is this old dough gives bakers an easy way to use a pre-ferment without having to mix a separate preparation in advance. It provides an organic acid enrichment and improvements in both taste and shelf life. The old dough always contains all of the ingredients found in the final dough, usually in the same proportion, being flour, water, plenty of yeast and salt, which allows a reduction in the first fermentation period of bread. 

NOTE: Professor Calvel is also credited with the development of the autolyse, a hydration rest early in the mixing and kneading process. He was Julia Child and Simone Beck's teacher for the bread chapter of Mastering the Art of French Cooking volume 2, as well as an advisor to the Bread Bakers Guild of America during its founding and early competitive efforts in the early 1990s. Calvel also wrote the book Le goût du pain, translated into English in 2001 as The Taste of Bread, as a summation of his work.

POOLISH (French)
It is a pre-ferment though to have been named for Polish bakers in France. It initially was used in pastry production. As its use spread throughout Europe it became common in bread. It is usually made with equal parts water and flour, by weight, with varying amounts of yeast, the amount decreasing proportionately with the length of fermentation desired (from 3 to 15 hours). The high water content makes the poolish very fluid and is typically fermented at room temperature, but can be done during a slow, slow cool overnight one using smaller amounts of yeast. This ensures the formation of milder sweet, wheaty flavor and helps with dough extensibility. In traditional French baking, a poolish is described in terms of how much water it contains, anywhere from one-third to four-fifths of the water used in the dough. 

SPONGE (English)
This is probably the easiest and most common starter. Generally, a sponge is like a thick pancake batter (or stiff), made from some of the flour, water and yeast in the recipe, but no salt. A regular sponge is usually faster than a poolish because it front loads all or most of the yeast in the sponge itself, where the final mixing can be done in less than an hour. It is often used in whole-grain and rich breads, improving the digestibility of the grain and lends some mild flavor, but not as drastically as a poolish. It does not contribute much extensibility to to a dough. Sometimes flour is sprinkled over the sponge, insulating it and preventing it from drying out. When cracks appear, it indicates that the yeast is growing and swelling. The less flour and the more liquid the consistency, the faster the growth of the sponge. 

SOURDOUGH STARTER (known as Levain, Barm, Wild Yeast, natural or wild yeast and bacteria) It is a natural leavening culture that can range from wet to firm consistency. It is the oldest form of making leavened Sourdough bread, which is thought to date back to the time of Moses, on the banks of the Nile. It is a biological leavening agent that posses the basic attributes of all living things, which are respiration and reproduction. A sourdough starter is cultured from wild yeast (Saccharomyces exiguus) and bacteria (lactobacilli), present on grains, such as flour, or, on the skins of fruit rich in sugars (grapes and plums), on you, and, in the environment. 

For bread baking, a culture of these yeasts and bacteria form naturally on a beginning mixture, typically of flour and water, exposed to open air, providing the surrounding environment remains temperate or slightly warmer and humid. This results in the beginnings of an alcoholic fermentation, which after several days will be followed by an acid fermentation. A portion of this starter is used as the sole leavening in bread dough. The resulting bread has a distinctive look and is high in natural acidity, giving the bread a tangy or wheaty and fruity or a mix of flavors that are multidimensional and complex, an interior crumb that is unique, sometimes surrounded by a crackly outer crust. The remaining sourdough starter requires ongoing maintenance of the fermented culture of yeasts and bacteria, and if successful, it can be kept alive for long periods of time, even for centuries and beyond. 

However, some bakers boost their starters with a little commercial cake yeast (up to 0.2 percent of the weight of the flour, or, with instant yeast, up to 0.6 percent of the flour), called levain de pâte or a mixed starter. However, the Sourdough mother culture or the original culture must remain free of commercial yeast.

SARAH SAYS: The San Francisco Sourdough is a starter that contains a specific strain of bacteria (Lactobacillus sanfrancisco), found only in the San Francisco Bay area. It is responsible for the bread's unique characteristics, found nowhere else, such as its unique sour flavor and thick crust. While sourdough starters have been around for thousands of years, the term "sourdough" is an American term that came into use during the California Gold Rush days of the late 1800's. Before the advent of commercial bakers' yeast, the settlers of the Western U.S. in the 19th century, carried starters with them for making bread. Folklore of the time abounds with stories of chuck wagon cooks making biscuits from barrels of starters and Alaskan gold miners sleeping with their starters at night to keep them from freezing. More stories are told of the tragedies of pioneer families losing their starters and of passing down highly prized starters from generation to generation.

Many California and Yukon gold miners obtained provisions in the booming coastal town of San Francisco before heading up into the mountains to stake their claims. Over time, it was discovered that starters from that area produced bread with a unique and particularly sour tang. Thus the starters and bread from that area because known as "sourdough". Later the term was even applied to gold miners themselves. More recently the term has generalized across the U.S. to mean simply a bread starter.

Although the miners did not know it at the time, particular strains of yeast and lactobacilli took up residence in starters from the San Francisco Bay area and they are responsible for the unique flavor identified as "San Francisco Sourdough." In the 1970's the microbes were isolated and identified.

To make your sourdough starter:
All you need is some organic flour (white, preferably rye or whole wheat), unchlorinated water (or bottled water), a temperate or even slightly warmer place and patience to start; it is usually made up of equal weights of flour and water, but can range from 50 percent water for a stiff starter to 125 percent water for a liquid one. The starter requires several refreshment feedings of the same and time to grow wild yeast on the flour and to attract bacteria from the environment. It takes about a week to achieve a starter with an adequate population of yeast with a good balance of friendly bacteria, and another two weeks until it is fully mature to be able to use as the sole leavening in your bread recipes. The stiffer starter ferments more slowly and does not require as cold a temperature to slow down fermentation and is thus, refreshed less often. It produces a mellower flavor than a liquid one.

Some professionals refer to sourdough starter as a Chef or Seed culture during the first stages of its development. When fully developed, it is referred to as a Sourdough culture, when it is strong enough to raise bread dough. A chef is usually started with organic whole wheat or rye flour, but organic white flour can be used, although it ferments more slowly. Once it is established, it is refreshed or fed with all white flour.