1. Making and Maintaining the Sourdough Starter:

1. Day 1: Mix 100g flour and 100g water in a glass jar. Stir well and cover loosely. Leave at room temperature.
2. Days 2-7: Feed daily by discarding half and adding 50g flour + 50g water. Stir well.
3. By Day 5-7, the starter should double within 4-6 hours of feeding. If so, it’s ready for baking.

2. Making the Sourdough Dough:

1. In a large bowl, mix 500g flour and 350g water. Let it rest for 30 minutes (autolyse).
2. Add 100g active sourdough starter and mix well.
3. Sprinkle in 10g salt and mix until combined.
4. Cover and let it rest for 30 minutes.

3. Bulk Fermentation and Stretch & Folds:

1. Every 30-45 minutes, perform a stretch and fold (grab one side, stretch it, and fold over). Repeat 3-4 times over 3-4 hours.
2. Let the dough ferment until it has risen by 50-75%.

4. Shaping and Final Proofing:

1. Lightly flour a surface and shape the dough into a tight ball.
2. Place into a proofing basket or bowl lined with a towel. Cover and let it proof for 4-8 hours at room temperature, or refrigerate overnight for better flavor.

5. Baking the Sourdough Bread:

1. Preheat oven to 475°F (245°C). Place a Dutch oven inside while heating.
2. Flip the dough onto parchment paper, score the top with a sharp knife, and carefully place it into the hot Dutch oven.
3. Bake for 20 minutes with the lid on, then 20 minutes uncovered for a crispy crust.
4. Remove from the oven and let it cool completely before slicing.