Sourdough starter, which we refer to as levain, is made by mixing flour and water, then leaving the mixture to sit, uncovered, at room temperature until the microscopic yeast cells and lactic acid bacteria (LAB) that are present in the flour begin feeding. Within days, you will see signs of fermentation. (You can also start a levain using a premade commercial culture if you want things to move along a little quicker; see page 48 of Modernist Bread at Home for our recommendations.)
In this blog, we’ll cover how to start a levain, what that process looks like, some things to be aware of, and some options for kick-starting your levain.
THE PROCESS
First, the flour and water mixture goes through an inoculation period, which is when the culture initially takes root and becomes active. This takes 4–5 days for a basic levain and requires regular maintenance by the baker. Yeast and LAB are voracious microbes and will exhaust the food stores in the original flour-and-water mixture if they are not replenished; for your colony to survive and thrive, you need to feed it. To do this, a portion of the levain is removed (and typically discarded, although you can save it for Second Chance Sourdough) and replaced with an equal amount of water and flour (a fresh store of food). The levain is fed on a regular schedule until fermentation has progressed to the point that the levain has sufficient leavening power and has produced enough lactic acid to achieve the degree of acidity that you prefer in your sourdough. At that point, a portion of the levain can be added to your bread dough.
Then you have two options: the first is to continue feeding and using the levain. You can keep that same levain going for months, years, or even decades, so long as you feed it every day at the same time. The other is to freeze the unused levain to use later. We’ll discuss feeding and storing in greater detail in the next lessons.
People often ask us if the pedigree of a sourdough starter is important. Our answer is that a long-lived levain will almost certainly change in composition over time. Think of it like a city; a great city may be just as grand two centuries from now as it is today, but it will have different inhabitants—some descended from the original residents and others who arrived later.
Overall, the pedigree of your levain isn’t crucial. As long as the levain is fed on the same schedule and kept at about the same temperature and level of hydration, it will ripen and mature as expected.
SOME THINGS TO KNOW
- The environment of a levain is known as a SCOBY (symbiotic culture of bacteria and yeast). Other fermented foods that rely on a type of SCOBY include kombucha and kefir.
- Before you use your levain’s storage tub or glass jar, wash it out with a mild soap (we suggest hand soap). Do not use sanitizing solutions; they could adversely affect the yeast and LAB.
- Practically all flours can be used to make a levain. Rye flours have many nutrients that favor yeast development. A new levain made with rye flour will usually be ready to be mixed into dough a few days before a white flour levain is.
- We do not recommend using high-gluten flours to start a levain.
- While many bakers swear by using inoculants, such as raisin water, to jump-start their levain, we found that approach was both unnecessary and ineffective. However, we did find some kick-starters that worked: chickpea flour and rye flour. You can learn more about this in Modernist Bread vol. 3:47, 57.
- Once you’ve started your levain, feed it once a day in cool months/environments and twice a day in hot months/environments.
- We recommend storing your levain at 21–24 °C / 70–75 °F.
- If you feed the levain regularly, it will develop more and more lactic and acetic acid flavors over time, which you’ll start to taste in your bread. The souring process levels off after about 10 days.
- The average inoculation time for a fresh starter made from flour and water is 4–5 days.
Eager to start your own? Take a look at our recipe for liquid sourdough starter/levain.
Further Reading
- Second Chance Sourdough recipe
- Liquid Sourdough Starter recipe
- How to start a liquid levain—Modernist Bread at Home, p. 51
- Sweet-and-sour starter recipe—Modernist Bread vol. 3:56
- Kick-starting your levain—Modernist Bread vol. 3:47, 57
- Premade commercial culture recommendations—Modernist Bread at Home, p. 48