How to Make a Sourdough Starter from Scratch

A step-by-step guide to creating your own sourdough starter using just flour and water. From Day 1 to your first bake in 7–10 days. **Day 1:** Mix 50g whole wheat flour + 50g water in a jar. Cover loosely. Leave at room temperature. **Day 2:** Discard half. Add 50g all-purpose flour + 50g water. Stir. Cover. **Days 3–4:** You may see bubbles — that's wild yeast! Repeat: discard half, feed 50g flour + 50g water. **Days 5–7:** The starter should be rising and falling predictably. It should smell pleasantly sour, not acetone-like. **Day 7–10:** Do the float test — drop a spoonful in water. If it floats, your starter is ready to bake with! **Maintenance:** Once established, feed your starter once a day at room temperature, or once a week in the fridge. To bake: take it out of the fridge, feed it, wait 4–8 hours until it doubles, then use. **Baker Thomas's Tip:** Use whole wheat or rye flour for the first few days — the bran contains more wild yeast and bacteria. Switch to all-purpose once it's established.