1. Day 1: Initial Mixing. In a clean, clear glass jar, combine 1/2 cup (120g) unbleached all-purpose or whole wheat flour with 1/2 cup (120g) filtered water. Mix thoroughly with a spoon until there are no dry spots and the mixture is smooth, like a thick pancake batter. Scrape down the sides of the jar. Loosely cover the jar with a lid, plastic wrap, or a clean kitchen towel. Do not seal it tightly, as the starter needs to breathe. Place the jar in a warm spot in your kitchen, ideally between 70-78 F (21-26 C).

2. Day 2: Rest and Observe. Do not feed your starter today. Simply observe it. You might not see much activity yet, but look for any small bubbles forming on the surface or along the sides of the jar. You might also notice a slight change in smell, perhaps a faint sour or yeasty aroma. Keep it in the same warm spot.

3. Day 3: First Feeding. By now, you might see some small bubbles, and the starter might smell slightly sour or vinegary. It’s time for the first feeding. Discard about half of the starter (approximately 60g or 1/4 cup). To the remaining starter, add 1/2 cup (120g) fresh flour and 1/2 cup (120g) fresh filtered water. Mix well until smooth. Loosely cover and return to its warm spot. Discarding part of the starter ensures that the active microbes have enough food to thrive without being overcrowded.

4. Day 4-7 (and beyond): Consistent Feeding. Continue the daily feeding routine. Each day, discard about half of the starter, then feed it with 1/2 cup (120g) fresh flour and 1/2 cup (120g) fresh filtered water. Mix thoroughly and loosely cover. You should start to see more vigorous activity: the starter will rise significantly after feeding (often doubling in size), become very bubbly, and smell pleasantly yeasty and sour. It should fall back down between feedings.

5. Look for Peak Activity. Your starter is considered “active” and ready for baking when it consistently doubles in size within 4-8 hours after feeding, shows many bubbles, and has a pleasant, tangy aroma. This usually takes 5-7 days, but can take longer depending on your environment and flour. A good way to test if it’s ready is the “float test”: drop a small spoonful of starter into a glass of water; if it floats, it’s ready to bake with.

6. Maintain Your Starter. Once your starter is active, you can maintain it by feeding it daily if you keep it at room temperature, or once a week if you store it in the refrigerator (feeding it 4-12 hours before refrigerating). Always feed it before baking.