Sourdough is bread leavened by a starter, a live mixture of flour and water that holds wild yeast and lactic acid bacteria. The yeast produces gas that makes the dough rise; the bacteria produce acids that give the loaf its tang and help it keep. To bake a first loaf you need a working starter, a long, slow rise and a hot oven.

This guide covers each stage in plain terms, with the mistakes that most often trip up beginners.

What you need

• A kitchen scale, since sourdough is easier to follow by weight than by cups
• Flour: bread flour for the loaf, plus whole wheat or rye to help the starter
• Water, and fine sea salt
• A glass jar for the starter
• A large bowl, a cloth or lid, and a Dutch oven or a heavy lidded pot

Making a starter

A starter is only flour and water left to ferment. A common method:

1. Mix equal weights of flour and water in a jar, such as 50 grams of each. Whole grain flour gives more microbes to work with.
2. Cover loosely and leave at room temperature.
3. Each day, discard most of the mixture and feed what remains with fresh flour and water in equal parts.
4. After roughly five to ten days, the starter should double in volume within several hours of feeding and smell pleasantly sour, like yogurt or beer.

Timing varies with temperature and flour. In a cold kitchen it can take longer. Bubbles in the first few days are normal and do not always mean the starter is ready. Wait until it rises predictably after each feeding.

Common mistake: using the starter too early. If it has not doubled reliably, the loaf will be dense.

Mixing the dough

A beginner-friendly loaf uses about 500 grams of flour, 350 grams of water (70 percent hydration), 100 grams of active starter and 10 grams of salt. Salt is about 2 percent of flour weight, a standard figure among bakers.

Mix flour and water first and rest for 30 minutes to an hour. This rest, called autolyse, lets the flour absorb the water and makes the dough easier to handle. Then add the starter and salt and work them in by hand.

Bulk fermentation

This is the first long rise, when most of the flavor develops. Leave the dough in a covered bowl at room temperature, and stretch and fold it every 30 minutes or so for the first two hours. To stretch and fold, grab an edge, pull it up and fold it over the middle, rotating the bowl.

Bulk fermentation might take four to eight hours depending on temperature and starter strength. Watch the dough, not the clock. It should look puffy, feel airy, and have grown by roughly half, with bubbles on the surface.

Shaping and the second rise

Turn the dough onto a lightly floured surface. Shape it into a round or oval by folding the edges to the center and creating surface tension. Place it seam-side up in a floured bowl or basket.

Cover and either proof for an hour or two at room temperature or refrigerate overnight. The cold slows the rise, gives a more complex flavor, and makes the dough easier to score. A weekly bread rhythm is described in the page on sourdough, olive bread and croissants.

Baking

1. Heat the oven and Dutch oven to around 450°F to 475°F (230°C to 245°C).
2. Turn the dough onto parchment, score the top with a sharp blade, and lower it into the hot pot.
3. Bake with the lid on for about 20 minutes, which traps steam and helps the loaf expand.
4. Remove the lid and bake another 20 to 25 minutes until deeply browned.
5. Cool on a rack for at least an hour. Cutting too soon leaves the crumb gummy.

Storing and keeping the loaf

Once cool, keep the loaf cut-side down on a board, or in a paper bag or bread bin, for a day or two. A crisp crust softens in plastic. For longer storage, slice and freeze the loaf, then toast slices straight from the freezer. Stale bread is not wasted: it makes good breadcrumbs, croutons and bread puddings.

Troubleshooting

• Dense, tight crumb: the starter was weak or the dough was under-fermented.
• Flat loaf that spread out: over-proofed, or the dough was not shaped tightly.
• Pale crust: the oven or pot was not hot enough, or the bake was too short.
• Too sour: a long cold proof and a high proportion of whole grain increase tang.

Sweet bakes and what comes next

Once the starter is established, it can be used for other bakes too, though sweet pastries have different rules. For the cake side of baking, the full-size cakes page shows how layered cakes are built.

Frequently asked questions

How do I know my starter is ready?

It doubles in size within roughly four to eight hours after feeding, has bubbles throughout and smells pleasantly sour. Consistency over several days matters more than a single good rise.

Can I make sourdough without a Dutch oven?

Yes. A baking stone or heavy tray plus a pan of hot water for steam works, though a lidded pot gives the most reliable crust.

How often do I need to feed a starter?

Daily at room temperature. If you bake less often, refrigerate it and feed it about once a week.

Is sourdough safe to eat?

Properly baked sourdough is safe for most people. It does contain gluten, so it is not suitable for anyone who needs to avoid it for medical reasons.