1. Day 1: Initial Mix. In a medium-sized glass jar or container (at least 1-quart capacity), combine 1/2 cup (113g) unbleached all-purpose flour and 1/2 cup (113g) filtered water. Stir well with a spoon or spatula until no dry flour spots remain and the mixture is smooth. It will be thick, like a paste. Scrape down the sides of the jar. Loosely cover the jar with a lid, plastic wrap, or a clean kitchen towel (allowing air circulation). Place it in a warm spot (70-75 F / 21-24 C) in your kitchen.

2. Day 2: Rest Day. Do nothing! Just let your mixture sit in its warm spot. You might see a few tiny bubbles starting to form, or nothing at all. Both are normal.

3. Day 3: First Feeding. Discard half of your starter (about 1/2 cup) from the jar. This step is crucial for managing the volume and concentrating the yeast activity. To the remaining starter, add 1/2 cup (113g) unbleached all-purpose flour and 1/2 cup (113g) filtered water. Stir thoroughly until smooth. Cover loosely and return to its warm spot. You should start to see more activity today or tomorrow.

4. Days 4-7 (or longer): Daily Feedings. Continue the process from Day 3: discard half of the starter, then feed it with 1/2 cup (113g) flour and 1/2 cup (113g) water. Stir, cover, and return to its warm spot. You should notice increasing activity each day: more bubbles, a slightly sour but pleasant smell, and the starter should rise significantly after feeding and then fall back down.

5. Look for the Peak. Your starter is ready when it consistently doubles in size within 4-8 hours after feeding, is very bubbly, and smells yeasty and slightly sour. It should also pass the “float test”: drop a small spoonful into a glass of water; if it floats, it’s ready to bake with! This usually happens between Day 7 and Day 10.

6. Maintain Your Active Starter. Once your starter is active, you can continue to feed it daily if you plan to bake frequently. If not, you can store it in the refrigerator and feed it once a week. We’ll cover more on maintenance later.