1. Remove from the Fridge and Discard: Take your sourdough starter out of the refrigerator. You’ll likely see a layer of dark liquid on top, called “hooch.” This is normal and indicates your starter is hungry. Gently pour off most of the hooch. Then, discard all but about 50-100 grams (1/4 to 1/2 cup) of your starter. This step is crucial to ensure you have enough food for the remaining starter to thrive.

2. First Feeding – Equal Parts: To the remaining starter in your clean jar, add an equal amount of flour and warm water. For example, if you kept 50 grams of starter, add 50 grams of all-purpose flour and 50 grams of warm water (around 75-80 F or 24-27 C). Stir everything together thoroughly until there are no dry spots of flour remaining. The mixture should have the consistency of thick pancake batter.

3. Mark and Wait: Place a rubber band or use a marker on the outside of your jar to indicate the level of the starter immediately after feeding. This will help you visually track its rise. Cover the jar loosely with a lid or plastic wrap (don’t seal it tightly, as the starter needs to breathe) and place it in a warm spot in your kitchen (around 70-75 F or 21-24 C).

4. Observe and Feed Again: After 8-12 hours, check your starter. You should see some bubbles forming, and it might have risen slightly. If it has risen and fallen, or if it’s just showing a few bubbles, it’s time for another feeding. Discard all but 50-100 grams of the starter again, and repeat Step 2 (add equal parts flour and water).

5. Repeat Until Active: Continue this feeding cycle (discarding and feeding equal parts flour and water every 8-12 hours) until your starter consistently doubles in size within 4-8 hours after feeding, and is full of bubbles. When you drop a small spoonful into water, it should float. This is your cue that it’s active and ready for baking.

6. Maintain or Refrigerate: Once your starter is active, you can use it for baking immediately. If you’re not baking right away, you can either continue feeding it daily on the counter or feed it one last time and place it back in the refrigerator for storage until your next baking session.