Starter. Sourdough starter. Levain. Starter sponge. Mother sponge. Biga. Chef. Poolish.
You'll hear many names for the stuff that makes your bread rise tossed about in recipes. What do they mean? And what exactly is the difference between them all?
They're All Preferments!
All of these names refer to types of preferments, a mixture of flour, water, and leavening agent (like yeast), combined in advance of making a bread dough. In the preferment, the water hydrates the flour, and fermentation reactions begin. The preferment is a head start for your dough. Using one makes your dough easier to knead and adds flavor to your bread.
Why So Many Names?
Different names developed in different locations. For example, "poolish" supposedly originated in France, where Polish immigrants introduced the idea of a preferment. These days, however, different people have different definitions for the same words, and there is no consensus or authority.
Some people say "levain" is simply the French term for starter. Some say that "sourdough starter" is specific to the starters created on the West Coast of the United States. Some use "starter" for the part of the mixture that you keep, and "levain" for the part that you mix up to use in your dough, but others use "storage leaven" for the keeper and "starter sponge" for the part that is used. "Chef," "mother," and "primary levain" are also used for the part you keep. And some people say the mixture changes names throughout the bread-making process.
Two Main Types of Preferment
Preferments can be sorted into two main categories.
- Preferments made with commercial yeast, which are mixed about a day before you mix the dough and used entirely.
- Preferments that contain wild yeasts and bacteria, which are maintained and then increased when needed for bread, and used over and over.
The second type of preferment is what we'll refer to as sourdough starter and what we'll look closer at to understand some of the science of sourdough.
Up Close with Sourdough Starters
A sourdough starter is created by mixing flour and water, and then allowing the microorganisms — wild yeasts and bacteria — that live in the flour and air to thrive and multiply. Over time, a stable population of these microorganisms develops. When used in bread, the microorganisms perform fermentation reactions, producing the gas that makes the dough rise and the molecules that give it flavor. These flavor molecules are different than those produced by commercial yeast.
Variations in Sourdough Starters Can Change the Flavor of Your Bread
In spite of the name, not all sourdough breads have a sour flavor. Time, temperature, and the presence of various types of bacteria can affect the final flavor.
- Time: A sourdough loaf baked the same day it is mixed will have a milder flavor than one that had a longer fermentation time. Some bakers even recommend using less starter in the recipe to extend the time it takes the dough to rise.
- Temperature: Different rising temperatures affect the activity of the yeasts and various types of bacteria, resulting in different flavors. Francisco Migoya, head chef and coauthor of Modernist Bread, shared that proofing at cold temperatures (that is, putting your dough into a fridge overnight) generally results in a harsher acidic flavor, while letting your dough rise out of the fridge results in a more mellow acidic flavor. Many bakers use combinations of the two temperatures; experiment with rising temperatures until you find the flavor you like best.
- Location: It's long been thought that the location where a starter is created affects its flavor. Research now shows that this might not be the case; the flour and conditions used are what's important. (We'll discuss this more in an upcoming post on the myths about sourdough starter.)
- Flour: Different types of flour can be used to create a starter: white, whole-wheat, rye, and others. The type of flour depends on what kind of bread you plan to make. For example, if you want to make a 100 percent rye bread, you'd need to maintain a rye starter. Sourdough starter made with white flour is the most common type.
- Wet vs. Dry: Different starter consistencies can be used. A wetter starter, which looks more like batter than dough, is more reactive, while a drier, dough-like starter is better for storing for longer periods in the refrigerator. Some bakers say that a wetter starter has a milder flavor, but Migoya's team found that a wetter starter produced a more acidic bread, with a stronger sour flavor. A wetter starter can more easily be mixed into dough. I found a drier starter easier to work with in the days before I had a scale, when I had to estimate the amount of starter used in dough; the dough-like consistency affected my dough less if my measurement was off.
Let's Call the Whole Thing Delicious
Wetter! Drier! Feeding schedules! Variable rising temperatures! Is starter worth it?
Maintaining a sourdough starter is more work than opening a packet of yeast, but the flavor that develops in sourdough bread is unlike anything else.
There's something fulfilling about using a starter to make dough rise. You've harnessed the power of nature, with no help from industry. And creating your own sourdough starter, from nothing but flour and water, can feel almost god-like. Curious? Then check out our recipe and get to work. And call it whatever you want.
The Soul & Science of Sourdough
Kitchn is partnering with Modernist Cuisine, the brilliant masterminds behind a new masterwork devoted to bread, Modernist Bread (November 7, The Cooking Lab), in our series The Soul & Science of Sourdough.
We're obsessed with sourdough bread and how it blends both soul and science, history and modernity, and we invite you to discover the magic of its fundamentals together. Bread is a treasured part of life — how can it fit in yours? Find out this month at Kitchn!