How To Start a Sourdough Starter

Before you dive into the specifics of making your own starter, it might help to know a little more about what you’re making, and what you aren’t.

Contrary to perceptions, using a sourdough starter doesn’t mean you have to end up with sour bread. “The purpose of the sourdough is to bring out the sweetness of the wheat,” says Michel Suas, the highly regarded founder of the San Francisco Baking Institute. This is why professional bakers take such pains to feed their starters frequently, with specific flours and at specific temperatures. When they get it all right, there’s barely a whiff of sourness in their loaves.

Some bakers, of course, like a sour loaf and aim for it (by letting their starter, or their dough, go through longer or warmer ferments). But you might want to know that sour bread is considered boorish to most bakers in France. In 1996, when Craig Ponsford, an American baker, was preparing for La Coup du Monde de la Boulangerie (the World Cup for bakers), he wanted to include a classic sourdough—of the truly sour kind made famous by his employer, Boudin, San Francisco’s 150-year-old bakery. Ponsford’s coach, who was French, said, “If you take that bread to Paris the judges will spit it out. That bread is a mistake!” Ponsford ultimately decided not to submit a San Francisco-style sourdough (but still used his starter for milder breads). That year, he became the first American to win the bakers’ World Cup.

If these considerations feel like too much trouble—and you believe your bread made with packaged yeast is plenty good, thank you very much—consider the history and tradition you become part of if you build your own starter.

All bakers who use sourdough know that once they create a beautiful starter, it can live through almost anything. (If neglected for weeks on end, it might get gray, flat, and smell like vinegar that’s gone bad. However, if you scrape off the top half and give it a few fresh feedings, your little darling might not be too happy, but it will eventually return to its creamy grandeur.) Even if abandoned for hundreds if not thousands of years, a sourdough starter might still show signs of life.

One indication of this possibility occurred last April, when an obsessive Egyptologist named Seamus Blackley was led to a microscopic cache of ossified, Egyptian bread yeast made some 4,500 years ago. After teaming up with an archaeologist, a biologist, and a Harvard museum, Blackley concluded that he had brought the yeast back to life; he even baked bread with it. To get the recipe properly dialed in, he used an ancient wheat varietal called Emmer, which, not coincidentally, has long been used in the Mideast. He then turned out loaves that apparently were sweeter than most modern sourdoughs, with a smooth crumb, almost like white bread.

There’s just one catch to this story. When any starter develops, one of the main organisms it spawns is a fast-growing bacterium called Lactobacillus sanfranciscensis (so named because it was first discovered in San Francisco, in 1971, not because it is unique to the city, or even to the San Francisco Bay Area). This family of bugs, along with the billions of others that add to a naturally fermented bread’s flavor, grow on virtually any flour within days (thus the list of easy steps above). Blackley admits that his team couldn’t be certain exactly which yeast or bacteria grew and fueled his bread. Since it took him a week to reconstitute a working starter, it’s entirely possible that he may have just grown a new starter.

If so, Blackley could still get authentically yeasted bread, because starters rebuild themselves constantly; that’s the nature of their beasts. This fact often comes as a surprise to bakers, even the pros. One day, when a San Francisco Baking Institute instructor was debunking various sourdough myths for a class of professional bakers, one shocked student said, “I was taught that one of the best ways to make a good starter is to ferment some grapes or raisins in water, then add flour, and about a week later you get a great starter.” That’s true, the teacher said. “You can also start with just flour and water and about a week later you get a great starter.”

OK, enough said. Let’s get started.

1. Fill a pint jar or medium-size glass bowl (vessel should be see-through) with 1/2 cup luke-warm water.
2. Add 1/3 c. of flour — ideally a mix of roughly 50% unbleached all-purpose (AP), 40% whole wheat (WW), and 10% rye flour.  If you don’t have rye flour, just use 1/2 & 1/2  AP & WW (no need to be exact).
3. Cover with a clean dish towel and place in a warmish area of your kitchen.
4. Roughly 12 hours later, dump about half of what you made, then add more water and flour mixture until the batch feels like thick pancake dough.
5. Cover with dish towel again, and rest as above.
6. Repeat this process for a day or two or three—whenever the mix begins fermenting (indicator species: lots of little bubbles, yogurt-like aromas). You’re aiming for twice a day, roughly every 12 hours, but if you don’t see or smell much evidence of growth, wait a few hours, or until you do.
7. Once you start seeing some fermentation activity, begin to feed more often, up to 3-4 times a day. Ideally, you want to do the feedings, or use the starter, when it’s still swelling—indicated by a bulbous surface—not when it’s collapsing, which it does when the little bugs have had their fill, and have begun to exhaust the flour’s nutrients.
8. When the starter begins looking like the photo below within 4-6 hours, and emits a well-balanced sourness, it’s done—and ready to be capped and either used or stored. If you bake more than once a week, it’s best not to refrigerate your starter—as long as you can store it in a cool place. If you go a week or more between bakings, you have to use a fridge; otherwise, the starter will turn gray, watery, and smell like bad vinegar. Nota bene: if that happens, this does not mean your starter is dead, merely that it needs a lot of TLC (dump most of it, re-feed, repeat, and keep repeating) until it regains its health and vigor.

If you want to get more precise, a much more detailed recipe, with photos of each step, is posted here, by Maurizio Leo of The Perfect Loaf. If you want to dig into the mysterious science behind all those bugs and bubbles, the “sourdough library” in Belgium has a few answers. And if you want to think about the whole process from the starter’s point of view, The New Yorker is here to help you.