How to Make Sourdough Bread: Starter, Fermentation and Baking Steps

Sourdough relies on wild yeast and bacteria captured from flour, rather than commercial yeast, to leaven dough. Baking it successfully means managing three linked processes: building and keeping a starter alive, fermenting a dough long enough to develop flavor and structure, and baking it under conditions that trap steam for a good rise and crust.

Building a starter from scratch

According to King Arthur Baking, a starter needs only flour, water and time. The mixture is made with equal parts flour and water by weight, left at room temperature, and then fed on a regular schedule, discarding a portion each time before adding fresh flour and water.

1. Combine equal weights of flour and water in a jar and let the mixture sit at room temperature.
2. Discard part of the mixture daily and refresh it with more flour and water, repeating this feeding cycle.
3. Watch for the starter to double in size within six to eight hours of a feeding, with bubbles throughout and slight sagging at the edges — signs King Arthur Baking lists as indicators of readiness.
4. Expect the process to take roughly five to fourteen days depending on conditions such as room temperature and flour type, per King Arthur Baking's beginner guide.

Maintaining the starter

Once established, a starter is kept alive through regular feedings. King Arthur Baking's standard maintenance method uses equal weights of starter, water and flour — for example 113 grams of each — after discarding the rest of the existing starter. The company's guide recommends weighing ingredients rather than measuring by volume, since a starter's thickness and how well it has been stirred can make volume measurements unreliable.

King Arthur Baking also notes that a neglected starter can usually be revived by returning to feedings every 12 hours until it becomes active again, then resuming its normal schedule. Leftover discard from feedings can be used in separate discard recipes, composted, or dried rather than thrown away.

Mixing and fermenting the dough

The Perfect Loaf's published beginner formula illustrates one full timeline from levain to loaf. A levain is built by mixing 38 grams of ripe starter with 38 grams whole wheat flour, 38 grams bread flour and 76 grams water, then fermenting it at 74–76°F (about 23–24°C) for five to six hours until it is visibly expanded and bubbly throughout.

1. Autolyse the bread flour with 603 grams of water for one hour before adding anything else, per The Perfect Loaf's method.
2. Mix in 190 grams of ripe levain, 50 grams of reserved water and 18 grams of salt, aiming for a final dough temperature of 78°F (25°C).
3. Bulk ferment the dough for about four hours at 74–76°F, during which it should rise 20–50% in volume and show bubbles on the surface and sides.
4. Perform three sets of stretch-and-folds during bulk fermentation, spaced 30 minutes apart: wet your hands, lift and fold one side of the dough over itself, rotate the bowl 180 degrees, and repeat on the remaining sides.

Shaping, proofing and baking

After bulk fermentation, The Perfect Loaf's formula calls for a short bench rest before shaping, followed by a long, cold final proof that develops flavor overnight.

1. Let the dough rest on the counter for about 25 minutes, then shape it into a boule using folding and dragging motions to build surface tension.
2. Rest the shaped dough on the counter for 20 minutes, then refrigerate it, sealed, at about 38°F for roughly 16 hours overnight.
3. Preheat a covered combo cooker or similar heavy pot to 450°F (232°C) for at least 30 minutes.
4. Score the cold dough, load it into the hot pot, and bake covered for 20 minutes to trap steam.
5. Remove the lid and bake roughly 30 more minutes, until the crust is browned and the internal temperature reaches about 208°F (97°C).

Common problems and fixes

Pantry Mama's troubleshooting guide identifies dense or gummy crumb as a frequent complaint, most often traced to an immature starter or a bulk fermentation that was cut short. The guide notes a starter generally needs about 14 days to become reliably viable, and recommends extending bulk fermentation time and strengthening the starter through consistent feeding as the main fixes.

• Underproofed dough: splits unevenly when baked, bakes into a cone shape that is wider at the base, develops a pale crust that resists browning, and spreads out rather than holding its shape when turned out of its basket, according to Pantry Mama.
• Overproofed dough: deflates like a balloon when scored, also browns poorly because the yeast has consumed most of the available sugars, and shows a weakened gluten structure.
• Fix for both: adjust proofing time and, for refrigerator proofing, confirm the fridge holds at 4°C (about 39°F) or below, per Pantry Mama's guide.