How to Make a Sourdough Starter and Bake Artisan Sourdough Bread at Home

A sourdough starter is a live culture of flour and water in which naturally occurring wild yeast and lactic acid bacteria grow, according to guides from King Arthur Baking and The Perfect Loaf. Unlike commercial yeast, it is not bought in a packet; it is cultivated at home over roughly a week and then kept alive indefinitely through regular feedings.

Building a starter from scratch

King Arthur Baking's method begins with whole-grain flour, which the company says is more likely to carry the wild yeast and bacteria needed to kick-start fermentation than refined all-purpose flour. The process runs on a roughly weeklong timeline before switching to twice-daily feedings.

1. Day 1: Mix 113g whole wheat or pumpernickel flour with 113g room-temperature water (68–70°F) in a non-reactive container. Stir until no dry flour remains, cover loosely, and leave at about 70°F for 24 hours.
2. Day 2: Discard half the mixture (113g), then feed the remainder with 113g all-purpose flour and 113g water. Cover and rest another 24 hours.
3. Days 3–5: Switch to two feedings roughly 12 hours apart. Each time, keep 113g of starter, discard the rest, and add 113g flour plus 113g water.
4. Days 6–7 and beyond: Keep feeding twice daily until the starter reliably doubles in size within 6 to 8 hours of a feeding, per King Arthur Baking's benchmark.
5. Separately, The Perfect Loaf's founder Maurizio Leo uses a higher-discard 1:5:5 ratio — 20g starter, 70g white flour, 30g rye flour and 100g water, fed twice daily — and recommends blending rye flour into the feed to speed activity and extend the interval between feedings.

Both sources set the same finish line: a starter is considered established once it predictably at least doubles between 6 and 8 hours after being fed, rather than on a fixed calendar day, since kitchen temperature changes the timeline. King Arthur Baking's own step-by-step guide lays out this process across roughly a week, with feedings continuing through Day 6–7 until the starter consistently doubles, and the company's troubleshooting advice is to replace a starter that still is not doubling within 8 hours after three to four days of consistent twice-daily feeding.

Signs a starter is ripe and ready to bake with

• Visible rise and bubbles on the top and sides of the jar.
• A fresh, fruity or balanced sour aroma rather than a flat or putrid smell.
• A loosening or softening of the texture as fermentation progresses.
• Reliable doubling in volume 6 to 8 hours after feeding — King Arthur Baking says if this does not happen after three or four days of consistent feeding, the starter should be replaced.

Feeding and storing a starter long-term

Once established, King Arthur Baking advises keeping the starter on the counter at 68–78°F and feeding it once a day if baking regularly. For less frequent baking, let the starter rest at room temperature for about two hours after a feeding, then refrigerate it; King Arthur Baking says it can stay refrigerated for days or even weeks between feedings. The Perfect Loaf's guide adds that a fridge-stored starter can go roughly two to three weeks between feedings during a break from baking, but should be revived with several room-temperature feedings before it is used to leaven bread again.

Each feeding typically involves discarding most of the existing starter and adding fresh flour and water in a fixed ratio — 1:1:1 by weight in King Arthur Baking's method, or the higher-ratio 1:5:5 Leo describes at The Perfect Loaf. Rather than throwing discard away, King Arthur Baking suggests using it in pancakes, biscuits, crackers or cakes.

Hooch, color changes and mold

A layer of clear or dark liquid, known as hooch, can form on top of a hungry starter; King Arthur Baking says this is not dangerous and can either be stirred back in or poured off before the next feeding — it generally signals the starter needs feeding more often. The company distinguishes this from contamination: any visible mold, or an orange or pink streak or tinge, means the starter should be discarded and a new one started, and the same applies if the starter smells putrid rather than sour.

Baking the loaf

King Arthur Baking's bake guide lays out the stages that turn a ripe starter into a loaf of bread, starting with an autolyse — resting the combined starter, flour and water for about 20 minutes before kneading in salt to let gluten begin forming without working the dough.

1. Bulk fermentation: after kneading, let the dough rise through two roughly one-hour periods, performing a letter-fold on the dough between them to build structure.
2. Shaping: pre-shape the dough into a round and let it rest about 20 minutes, then shape it into a tight final round or batard and place it seam-side up in a floured banneton or cloth-lined bowl.
3. Final proof: let the shaped dough rise until light and airy, roughly 2 to 2.5 hours at room temperature, according to King Arthur Baking.
4. Scoring: just before baking, slash the top with a sharp blade or lame — King Arthur Baking says this gives the loaf a pre-designated spot to expand as it bakes.
5. Baking: preheat the oven to 450°F with a baking stone, generate steam (King Arthur Baking's method pours boiling water into a cast-iron pan), and bake about 35 to 40 minutes until crusty and golden.

King Arthur Baking's own guide does not specify a Dutch-oven method, but it is a widely used home alternative to a baking stone and steam pan for achieving a similar crust.

How the two main approaches compare