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How to Make a Sourdough Starter from Scratch
A sourdough starter is just flour, water, and time. Wild yeast and friendly bacteria move in, and within one to two weeks you have a living leaven that can raise real bread. Here is the day-by-day plan.
What you need
- A jar (roughly 750 ml, with a loose lid)
- Flour: unbleached all-purpose or bread flour. A spoon of whole wheat or rye speeds things up.
- Water: room temperature, filtered or dechlorinated if your tap water is heavily treated
- A scale: sourdough works in grams, not cups
The day-by-day schedule
| Day | What to do | What you will see |
|---|---|---|
| 1 | Mix 60 g flour + 60 g water. Cover loosely, leave somewhere warm. | A plain paste. Nothing yet. |
| 2 | Rest. No feeding needed. | Maybe a bubble or two. |
| 3 | Discard half. Feed 60 g flour + 60 g water. | First real bubbles, a sour smell. |
| 4–6 | Discard half and feed once (or twice) daily. | Often a strong rise, then a discouraging quiet stall. Normal. |
| 7–14 | Keep the daily rhythm. | Predictable doubling within 4–8 hours of feeding. |
The day 4 stall is normal. The early boom is caused by bacteria that die off before the real yeast establishes. Almost everyone thinks they killed their starter this week. You did not. Keep feeding.
How to know it worked
Your starter is ready to bake with when it doubles reliably within 4–8 hours of a feeding, has a bubbly, airy texture, a domed top, and smells tangy like yogurt rather than like nail polish. That usually lands between day 7 and day 14, colder kitchens take longer.
Common early mistakes
- Skipping the discard. Without discarding, the starter grows huge and too acidic for the microbes you want.
- A cold spot. Below about 20°C (68°F) everything slows dramatically. The top of the fridge or inside the oven with the light on works.
- Chasing day counts instead of behavior. Ready is a behavior (reliable doubling), not a date.
Let AI confirm every stage
Sourdoughy builds this exact day-by-day plan for your kitchen, reminds you at feeding time, and reads a photo of your jar each day to tell you which stage your starter is really in.
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