Apollonia Poilâne’s Homemade Sourdough Starter Recipe

A sourdough starter is an acidic community of natural yeasts and bacteria used to leaven bread and add flavor. Sourdough starter has a lot of nicknames—pre-ferment, levain, leaven, la mère—but it all starts with a bit of flour and water left out to allow the growth of yeast. Most starters also contain lactic acid bacteria—the same bacteria that give yogurt and fermented pickles their tangy flavor.

Making a sourdough starter means that you’re nurturing wild yeast in a small amount of dough. This combination kick-starts fermentation—hence the name “starter”—in bread dough. Water activates the wild yeasts in the starter, then the yeasts digest sugars in the flour, which releases carbon dioxide gas. The resulting gas bubbles allow bread to rise by expanding within the elastic gluten network of bread dough.

With commercial yeast readily available, many people choose not to foster their own yeast. However, baking sourdough bread with your own leavening agent has a number of advantages:

1. 1. Shelf life: The lactic acid bacteria found in sourdough starters slows down the staling process, while the acidity of the bread inhibits microbial growth and mold.
2. 2. Flavor: Unlike bread made with commercial yeast alone, sourdough has a unique taste that reflects its environment.
3. 3. Texture: Those lactic acid bacteria made from at-home yeast improves the texture of the bread, yielding crisp and chewy loaves.

The basic formula for making a sourdough starter involves combining flour and water in a one-to-one ratio and leaving it out at room temperature, covered with a clean cloth, until it starts to bubble and rise. This is a sign that the yeast are actively digesting the carbohydrates in the flour and will need to be replenished soon. Although the process is simple, there are a few factors you’ll want to consider:

1. 1. Choose a thickness that is easy to work with. Some people prefer a slightly thicker starter, while others keep their starters fairly thin. Choose a thickness that is easy for you to work with, and will incorporate well into your favorite sourdough bread recipe.
2. 2. Experiment with different flours. Most bakers like to use a base of all-purpose flour, since it’s affordable and neutral-tasting, supplementing with a bit of whole-grain flour (such as whole wheat or rye flour) to provide the yeast with extra nutrients. Experiment with different flours to find what works best for your unique community of wild yeast.
3. 3. Be mindful of chlorine in your water. When it comes to water, regular room-temperature tap water works best, unless your tap water contains high amounts of chlorine, which can kill the beneficial bacteria in your starter.
4. 4. Kick-start fermentation with add-ons. All you need to attract wild yeast is flour and water, but you may prefer to kick-start fermentation by introducing extra lactic acid. Baker Apollonia Poilâne suggests adding a little yogurt to your new starter as a way of introducing lactic acid bacteria. Another strategy is to add some unwashed, organic grapes to your starter, since their skins are covered in natural yeast.
5. 5. Pour off the alcohol. When the wild yeast have consumed all available sugars in your starter, they’ll begin to produce alcohol, which you’ll notice as a funky-smelling thin layer of clear liquid on top of your starter/ dough. If this happens, pour off the liquid and feed your sourdough. Alcohol production is an indicator that it’s time to feed your starter, but you’ll ideally feed your sourdough before that happens. The alcohol is not helpful for getting your bread to rise.

There are a few factors to consider when storing your starter. They are:

• Temperature. Yeast thrives between 68 degrees Fahrenheit and 77 degrees Fahrenheit (or 20 degrees Celsius to 25 degrees Celsius). If the starter is too hot, bacteria may overtake the yeast. If the starter is too cold, it won’t ferment at all. If room temperature is too cold for your starter, you can try placing it in a turned-off oven with just the oven light left on for warmth.
• Drafts. Starter that’s stored in a drafty place—like near a window or door—might form a crust. Keep your sourdough in a hospitable location.
• Fermentation pace. Keeping your sourdough starter in a cold place, such as the refrigerator, will significantly slow down fermentation, allowing you more time between feedings. Just make sure to bring your starter to room temperature a couple of days before you plan to bake.