Bread Preferments

A bread starter, also called preferment, is just what it sounds like: a mixture of water and flour that has been colonized by yeast and other friendly bacteria to provide a starting point for new batches of bread. It is a mixture of dough components which is allowed to ferment before it is added to a bread mix. Starters begin with just a mixture of flour and water. Bakers either add active dry yeast, or allow the mixture to collect naturally occurring wild yeast and bacteria from the environment (soudough starter) as the first step in making bread and other doughs.

Preferments represent the art, science and craft of baking. These are at least as old as bread itself. Primitive dough leavening involves letting the flour and water be colonized by yeast and bacteria naturally present in the air. The accompanying fermentation reactions are responsible for the mellowing and acidification of dough that ultimately modify the sensory characteristics of baked goods.

The following terms are all “preferments”: chef, pâte fermentée, levain, sponge, madre bianca, mother, biga, poolish, sourdough starter.

Why Use a Preferment?

Because fermentation is extended, the yeast and natural enzymes present in flour have time to take action on the starches and proteins in the dough, releasing a larger amount of food supply for the yeast to ingest and turn into energy. This has a couple of distinct benefits:

  1. It tastes better. The general rule of thumb is the longer the bread is allowed to ferment, the more complex and delicious the finished flavors will be. Breads made with preferments often possess a subtle wheaty aroma, delicate flavor, a pleasing aromatic tang, and a long finish. Organic acids and esters are a natural product of preferments, and they contribute to superior bread flavor. This does have a law of diminishing returns however; any preferment older than 3 days that hasn’t been refreshed with fresh flour and water is likely to have a weak and dying yeast population which can give your bread off flavors and poor rising ability.
  2. Dough structure is strengthened. Preferments add extensibility to bread doughs, making them easier to form, and resulting in a superior oven spring. In fact, preferments have been shown to increase the oven spring of baguettes by as much as 10%, which results in an airier, lighter crumb. A characteristic of all preferments is the development of acidity as a result of fermentation activity, and this acidity has a strengthening effect on the gluten structure.
  3. Keeping quality improves. Delayed fermentation will also slightly drop to the pH of bread, extending it’s shelf live without the necessity of “dough conditioners” or preservatives. There is a relationship between acidity in bread and keeping quality. Up to a point, the lower the pH of a bread, that is, the higher the acidity, the better the keeping quality of the bread. Historically, Europeans, particularly those in rural areas, baked once every two, three, or even four weeks. The only breads that could keep that long were breads with high acidity, that is, levain or sourdough breads.

Ingredient Percentages

To calculate the amount of ingredients you should use in a preferment (excluding Pâte fermentée, or old dough) : A good range for the weight of the preferment flour is 20 to 30% of the total weight of flour in the recipe—so let’s say 25%. So a recipe that uses 25 ounces of flour: 25.00 ounces x 0.25 = 6.25 ounces. This will be the base amount of flour for the preferment. From there, we have to take the ratios from the preferment itself (for example for a biga, 55% water and 0.25% yeast - see below) to determine the amounts of the other ingredients.

It must be kept in mind that the baker will manipulate the quantity of yeast in his or her preferment to suit required production needs. For example, in a bakery with two or three shifts, it might be suitable to make a poolish or any other preferment and allow only 8 hours of ripening. In such a case, a slightly higher percentage of yeast would be indicated in the preferment. On the other hand, in a one-shift shop, the preferment might have 14 to 16 hours of maturing before the mixing of the final dough. In this case the baker would decrease the quantity of yeast used.

The baker should keep in mind that a sluggish and undeveloped preferment, or one that has gone beyond ripeness, will yield bread that lacks luster, and suffers a deficiency in volume and flavor.

Various Types of Preferments

Preferments can go by many different names including chef, levain, sponge, madre bianca, mother, biga and poolish.

Hydration, in baker’s parlance, refers to the ratio of flour to liquid. A "stiff" preferment has low moisture and the consistency of bread dough. On the other end of the hydration spectrum, a "liquid" preferment has the consistency of pancake batter.

Commercial Yeast Breads

Many breads are leavened by yeast. The yeast used for leavening bread is Saccharomyces cerevisiae, the same species used for brewing alcoholic beverages. This yeast ferments carbohydrates in the flour, including any sugar, producing carbon dioxide. Most bakers in the U.S. leaven their dough with commercially produced baker's yeast. Baker's yeast has the advantage of producing uniform, quick, and reliable results, because it is obtained from a pure culture.

Yeast is a living microorganism until it is destroyed by heat. As yeast grows and multiplies it gives off carbon dioxide which causes the dough to rise. Its action is affected by the addition or deletion of other ingredients such as salt and sugar. Using less yeast than specified in a recipe causes the dough to take longer to reach the desired volume in the rising stages.

Many yeast breads are made from:

Yeast Preferments

Pâte fermentée (Chef, Old Dough) is a French term that means fermented dough, or as it is occasionally called, simply old dough. The “old dough” or pâte fermentée style of preferment is extremely convenient if you’re baking the same bread recipe on a regular basis. If one were to mix a batch of French bread, and once mixed a portion were removed, and added in to a new batch of dough being mixed the next day, the portion that was removed would be the pâte fermentée. Over the course of several hours or overnight, the removed piece would ferment and ripen, and would bring certain desired qualities to the next day's dough. Being that pâte fermentée is a piece of mixed dough, we note that it therefore contains all the ingredients of finished dough, that is, flour, water, salt, and yeast.

Old dough leavening tends to create a loaf which is more complex, with a wider range of flavors, and many people enjoy using it. This approach was championed by famed French baker Raymond Cavell who credited this method with adding complexity of flavor and increased oven spring to his world famous baguettes.

An old dough leavening is a truly unique leavener, harnessing the specific yeasts of a particular region and creating an individual flavor which will be distinctive. Some of this leavening is famous, and it has been carefully husbanded by its parent bakery for decades, ensuring that customers experience the flavors they are familiar with every time they buy bread.

The basic concept is simple; up to 1/3 of bread dough is reserved after the bulk fermentation to levin the next batch of bread. So in the case of a classic baguette, the first time the recipe is made, flour, water, yeast, and salt will be mixed together and allowed to bulk ferment. After the bulk fermentation is complete, the dough is punched down, one third is reserved to levin the next batch of bread, while the rest of the dough is scaled, formed, proofed, and baked.

This old dough can be stored for about 8-12 hours at room temperature or retarded in the refrigerator for up to 3 days. It can also be frozen for up to 6 months, removing from the freezer and allowing to thaw fully (about 12-16 hours at room temperature, 24-36 hours in the fridge depending on the dough's volume) before using it to levin a batch of bread.

Being that pâte fermentée is a piece of mixed dough, we note that it therefore contains all the ingredients of finished dough, that is, flour, water, salt, and yeast.

“Biga” is a term for a type of starter made with dry active baker’s yeast, used primarily in Italian baking, and has a high ratio of flour that makes it more similar to a dough. Ciabatta and Foccacia, and other popular Italian breads, are often made using biga starters. Biga is known for helping create bread with a light texture and lots of airy holes. Biga starters are dry and thick compared to other starters, usually made with more flour than water. Most professional bakers use the Baker’s Percentage to make their starters. For example, a biga recipe might call for a ratio of 100% flour to 60% water, so a baker would mix 10 pounds of flour with six pounds of water to create what is known as 60% hydration. Yeast would be 0.25%. Note that there is no salt in the biga. Unlike pâte fermentée, which is simply a piece of mixed white dough which is removed from a full batch of dough, the biga, lacking salt, is made as a separate step in production.

This style of preferment was developed by Italian bakers, and in Italy, a Biga refers to any style of preferment that contains flour, water and yeast, no matter the percentages. However, it’s more common for a Biga to have less hydration than other preferments. Ciabatta is an example of Italian bread that uses a biga. It is made with flour, water, and a small amount of yeast (the yeast can be as little as 0.1% of the biga flour weight). Once mixed, it is left to ripen for at least several hours, and for as much as 12 to 16 hours. Note that there is no salt in the biga, which is added later.

The difference between Ciabatta and Focaccia is that a proper ciabatta starts with a biga (a yeast starter) while a focaccia doesn't use a biga. So when they are baked, a focaccia is a little denser, while a ciabatta is light and full of holes. And the denser crumb of focaccia makes for a bread that is easier to add things to like more olive oil, olives, whole fresh spices and cheese, whereas the lightness of a ciabatta is enjoyed plain.

For the sake of understanding various approaches to preferments, Biga’s are low hydration (stiffer) and take longer to finish fermentation as compared to a poolish containing the same percentage of yeast. This is because yeast’s movement is impeded by lower hydrations, taking them longer to propagate and consume all the starches contained within the bread dough. This is why Biga Preferments will usually, but not always, contain more yeast based upon the flour’s rate (about 1%) than a wetter style of preferment like a poolish. At the one percent use rate, a biga preferment left at a standard room temperature will be ready to use in about 14-18 hours. The basic formulation for a biga starter is: 500g Flour - 100%, 300g Water - 60%, 5g Yeast - 1%.

Once a biga preferment is airy and full of life (and expanded by about double it’s original volume), it can then be incorporated into the final dough formulation by cutting into small pieces, mixed with the rest of the recipe’s liquid, and then incorporated into the remaining ingredients. This will ensure an even dispersion of yeast contained in the preferment, resulting in better bulk fermentation and proofing.

"Poolish" is the term for the type of starter most often used in French baking using the sponge method. Like biga, poolish is also made using a dry active baker's yeast, but the starter is made much wetter than a biga. It is very soft and batter-like. A poolish is usually made with a one-to-one ratio of flour and water by weight, so 100% flour and 100% water, according to the baker's percentage, and 0.25% yeast. Its origins are Polish, and it was first used in the mid 1800s. It initially was used in pastry production. As its use spread throughout Europe it became common in bread. Poolish is allowed 12 hours fermentation time before being mixed into the dough. The most famous example of poolish is the preferment of choice for Classic Baguettes, country loaves, and other crusty breads.

Poolish was one of the first preferments elaborated with commercial yeast. Polish bakers, where the name originated, are credited with inventing this preferment in Poland at the end of the 19th century. The process then was adapted in Vienna, Austria and later in France. Bread made with a poolish was lighter and less acidic than the sourdough bread commonly baked during that time, and it started to gain popularity. With the availability of commercial yeast, more bakers began using the poolish process, and the sourdough process declined.

The poolish style preferment is the most common approach used by enthusiasts and professional bakers alike, mainly because it’s high hydration allows the yeast to propagate at a constant pace, and it’s incredibly easy to apply a preferment to any bread recipe since it contains a 1:1 ratio of flour and water (that is, it is 100% hydration), and a small portion of yeast. Note the absence of salt. More yeast is usually added to this when it is mixed with flour to make the final dough, but not always. Based on the baker’s percentage, a poolish starter will have 100% hydration and .2% yeast (always based on the flour’s weight). This means the basic formulation for a poolish preferment is: 500g Flour - 100%, 500g Water - 100%, 1g Yeast* - 0.2% (either active or instant dry).

Once mixed, a poolish style preferment will be ready to use in about 12-18 hours, assuming an ambient room temperature of 68-72°F/20-22°C and your yeast usage doesn’t exceed .2% based on the flour’s weight. Remember, the more yeast used and the hotter your room temperature, the sooner your preferment will be ready (which isn’t necessarily desirable since the whole purpose of a preferment is to slow down the fermentation process). For every 17°F/9°C your room temperature raises or drops, the yeast activity will be doubled or cut in half, taking the yeast half the time or twice the time respectively to achieve the same amount of fermentation.

The poolish is most active when it is just on the brink of collapsing, when the bowl is gently tapped. The challenge is to find that 'brink' point of course, before the collapses. One of the tell tale signs is the poolish starting to get a bit foamy before collapsing. If you wait even longer the poolish will because soupy, all gluten have been broken down by the yeast, you can stir it with a spoon without noticing any structure.

Poolish is primarily used in breads and increases the rise plus adds a chewy crumb and a slight sourdough flavor. The most famous example of poolish is the preferment of choice for Classic Baguettes. In addition to its "nutty" flavor, poolish can make baguette doughs easier to handle – the preferment boosts extensibility (the ability for dough to stretch).

The Sponge Method, aka Yeast Starter or Yeast Pre-Ferment, is a two-step mixing process in bread baking. The first step is mixing the yeast with the liquid, and half the flour of the entire recipe/formula to create a thick batter, also known as the Sponge. The Sponge is then set aside to rise for a certain amount of time. In the second step, the remaining ingredients of the recipe/formula are incorporated into the sponge. The dough is then kneaded and set aside to rise until doubled in size. This two-step method helps to enhance the flavor of the bread, helps to create a lighter texture, and an improved shelf-life.

Sponge is unique in that it contains all the yeast of a recipe and a lot of times it would also contain all the liquid of that recipe. It is also unique because unlike the slow fermented nature of the other three preferments, this one is quick and explosive taking as little as 45 minutes to be ready. Such a preferment is mostly used in enriched dough (butter rolls, cinnamon buns, babka and the like) which does not requite that much acidity and complexity. It will still give the bread more character and improve the keeping quality further even though fats in enriched dough do that too. Unlike the other three preferments this one is the main leavening agent in the recipe so you really must not let it over ferment.

Originally, sponge was used as preferment in pan bread production in England. A regular sponge is much like a poolish, except that most or all of the yeast is added at this stage. It ferments much faster, so there isn't as much flavor development as with a poolish. However, this type of preferment allows bread to be made faster, since it might sit for as little as 20 minutes or an hour before the rest of the ingredients are added. More yeast might be added at that stage, but much less than with a poolish.

The sponge which can be made with milk instead of water. One reason for a sponge being used in a recipe made with milk is the obvious problem that milk does not last well out at room temperature.

A sponge also should be used after it has reached full maturation. As with the poolish, the surface of the sponge contains vital clues to help bakers determine its readiness. When many bubbles are evident and some cracks start to form, crating some collapsing, the sponge is ready for incorporation into the final dough. An under-mature sponge would not be as beneficial because of inadequate acid development;' an over-mature sponge could negatively affect the strength of the dough due to an increase in the acidity level. It also would affect the flavor of the bread due to the formation of other acids.

If you are working with pre-fermented doughs like poolish or biga make sure not to ‘over ripe’ your pre-ferment. This is especially true when using larger percentages of preferment in your final dough (think up to 50%) because over riping will kill the gluten in your preferment (the yeast will eat them all) and you will end up with a weaker and hard to handle dough.

To use a sponge, follow this formula: from your bread recipe use 30% of the total flour for the sponge. Add an equal amount (by weight) of water and all or half of the yeast. You’ll know your sponge is ripe and ready to use when the batter is slightly bubbly. Add this sponge with your remaining liquid ingredients and proceed with your recipe as usual. 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.

Sweet dough and whole grain breads, in particular, will get the most benefit from the sponge method. Because of its stiffer consistency, the sponge will improve the strength of the dough. This increase in strength is usually enough to compensate for the potential weakening of the gluten generated by the sugar and fat frequently found in sweet bread formulas, and the heavier grains in whole grain bread. It should be noted that the sponge mixing method can be used for any bread recipes even if it doesn’t specifically call for this method.

A sponge will provide a leavening boost to doughs and create a more open crumb. Many bread recipes call for a sponge method, especially traditional French breads. Some examples of breads that use the sponge method: Brioche, Portuguese sweet bread, Stollen, as well as pancakes, crepes, and pop overs.

Unfortunately today the sponge process has been replaced by the straight dough method with dough conditioners replacing the sponge. Sponges were, and still are, also used in the  production of sweet dough.

Sourdough Breads

At their core, both a sourdough starter and a levain fall under the category as a preferment. They each are mixed ahead of time, left to ferment, and then either used directly in the dough (levain) or refreshed to keep the culture alive (starter, as in soudough starter). Basically, a starter is a stable mixture of beneficial bacteria and wild yeast that's maintained with regular refreshments and is used to leaven and flavor dough.

A levain, also called a leaven or levain starter, is an off-shoot of your sourdough starter, and it's a mixture of fresh flour, water, and some ripe starter. This mixture will be used entirely in a batch of dough and has the same fate as the bread dough you're mixing: you will bake it in the oven. But before that, it's your preferment for the day's dough, meaning it will leaven your dough (make it rise) and be responsible for the flavor produced through the byproducts of fermentation. Because the term levain is French for leaven, which is almost always taken to mean naturally fermented bread, the term levain is often used synonymously with sourdough at least in the US.

This pre-ferment propagates naturally occurring yeast and bacteria (usually Saccharomyces exiguus, which is more acid-tolerant than S. cerevisiae, and various species of Lactobacillus). Sourdough bread usually isn’t punched down like regular bread; instead, handle it gently to avoid deflating or collapsing the gluten structure.

Sourdough starters have been used for centuries to provide tried and true results. This type of starter is made from wild yeasts that occur naturally in the environment, such as lactobacillus and acetobacteria, which take up residence in a batter of flour and water. These yeasts are slightly more microbiologically complex than the dry active yeasts in Biga and Poolish starters. Sourdough starters, unlike others, are often maintained in stable colonies for long periods of time, even centuries, since it is simpler to maintain this type of starter than to remake it. As long as the starter is properly fed and cared for, it can be kept active for years to provide predictable results over and over again. Sourdough starters are given between 24 and 36 hours of fermentation time before being mixed into the doughs.

The sour taste of sourdoughs actually comes not from the yeast, but from a lactobacillus, with which the yeast lives in symbiosis. The lactobacillus feeds on the byproducts of the yeast fermentation, and in turn makes the culture go sour by excreting lactic acid, which protects it from spoiling (since most microbes are unable to survive in an acid environment). Formerly all yeast-leavened breads were sourdoughs, and the leavening process was not understood until the 19th century, when with the advance of microscopes scientists were able to discover the microbes that make the dough rise.

A sourdough starter is essentially a dough-like or pancake-batter-like flour–water mixture in which the yeast and lactobacilli live. A starter can be maintained indefinitely by periodically discarding a part of it and refreshing it by adding fresh flour and water. (When refrigerated, a starter can last weeks without needing to be "fed".) There are starters owned by bakeries and families that are several human generations old, much revered for creating a special taste or texture. Starters can be obtained by taking a piece of another starter and growing it, or they can be made from scratch.

Keep in mind, however, that when using white flours, unbleached and unbromated flour are the appropriate choice. Vital nutrients are lost during the bleaching process, making bleached flour unsuitable.

Note: The sourdough bread that uses a stiff perferment is traditional dark rye breads. Rye Starter is crucial because the acidity from fermentation aids in strengthening the dough. You can make decent rye bread without a stiff starter – much in the same way that you can make a baguette without a poolish – but now you know why this style of perferment lives in so many traditional rye recipes.

Bacteria - Salt Rising Bread

Salt rising bread employs a form of bacterial leavening that does not require yeast. Although the leavening action is not always consistent, and requires close attention to the incubating conditions, this bread is making a comeback due to its unique cheese-like flavor and fine texture.

To make salt-rising bread, you make a starter. There are a variety of varying recipes, and many of them have been passed down for generations, but usually a starter is made by cornmeal or potatoes, flour and milk, left in a warm place overnight. By morning it’s foaming and funky ("a rotten cheese smell" as one recipe puts it), at which point warm water and flour are added to the mixture and it’s left to rise a little longer. But salt-rising bread, dependent on a natural fermentation process, is a fickle beast, and even those who have baked it for decades will acknowledge how temperamental the starter and bread can be. "At times, the failures seem to be due to weather, low barometric pressure or a change in the ingredients." "For example, the starter may never develop a foamy top. Or the starter will work beautifully, but the sponge doesn’t double in size. At times, the sponge rises well, but the loaves take hours to rise, if they even rise at all. One has to expect such variance with wild bacteria."

But if you do come across a commercial variety, be wary. "I must tell you that most commercial bakers of salt-rising bread almost always add commercial yeast to their starters, as this always ensures a successful batch of bread."

"Another reason that the bread may not be as popular is that it is much more difficult and time consuming to make than sourdough bread … salt-rising bread takes a long time to make, about 16 to 18 hours, and few people nowaday want to take the time.

Recipe for Salt Rising Bread
Early Salt Rising Recipes

What Is Autolyse?

In bread baking, autolyse is best described as the hydration rest following initial mixing of only flour and water that occurs before kneading has fully developed the gluten; this simplifies the shaping process of the finished dough. Autolyse is the resting period that takes place after the water and flour are mixed, but before it is kneaded. It combines the remaining ingredients (although sometimes salt is added after) and allows the flour to hydrate and the gluten to start to develop. This rest gives the flour an opportunity to absorb the maximum amount of water.

Autolysis refers to the destruction of a cell by its own enzymes, or “self-splitting”. In baking, this means that enzymes in flour (amylase and protease) begin to break down the starch and protein in the flour. The starch gets converted to sugar, and the protein gets reformed as gluten.

Why would you want to do this? When you knead the dough, aren’t you just trying to do the same thing – form gluten? Well, yes, ultimately; but when you knead dough, you also oxidize it (expose it to oxygen). Over-oxidized (or, over-kneaded) dough results in color and flavor loss in a finished bread, which means it’s pale and tasteless. By giving the mixed flour and water time to go through autolysis on their own, you achieve the same result, but without any of the unpleasant effects of oxidation. Additionally, an autolyse period gives the flour time to soak up all the moisture, resulting in more orderly gluten formation.

What this all means for your bread is that your dough will be easier to handle before it’s baked, and the end product will taste better, have better texture, look better, and have better keeping qualities.

All you have to do is mix your flour and water together (no yeast, and never any salt!) until the flour is all moistened, cover it, and just step away for about 20 minutes.

Why (and How) to Slash Your Bread Loaf

The patterns that appear on top of artisanal breads are not just ornamental: Beyond making an attractive loaf of bread, the slashes open up the structure and alleviate the pressure that builds up during baking. Slashing the top of dough before it bakes allows it to rise properly. Since bread rises so rapidly during baking, an un-cut dough may crack at the weak points. By having the chance to cut the dough beforehand, you are predetermining where the bread will “crack,” making sure it is done uniformly for more even baking.