1. Retrieve Your Starter: Take your sourdough starter out of the refrigerator. It will likely look dormant, perhaps with a layer of dark liquid (hooch) on top. This is normal.

2. Assess and Discard (if necessary): If there’s hooch, gently pour off most of it. If your starter hasn’t been fed in a very long time and has a strong, unpleasant smell or mold, it might be best to discard it and start fresh. Otherwise, proceed.

3. Measure Out Starter: In a clean jar or container, measure out a small amount of your dormant starter. A common ratio for feeding is 1:1:1 (starter:flour:water by weight). For example, if you want to end up with 100 grams of active starter, you would take 25-50 grams of your dormant starter.

4. Add Flour: Add an equal weight of flour to your measured starter. So, if you used 50 grams of starter, add 50 grams of flour.

5. Add Water: Add an equal weight of room-temperature filtered water to the mixture. Again, if you used 50 grams of starter and 50 grams of flour, add 50 grams of water.

6. Mix Thoroughly: Stir the mixture well with a spoon or spatula until all the flour is fully incorporated and there are no dry pockets. The consistency should be like a thick pancake batter.

7. Cover and Wait: Loosely cover the jar with a lid, plastic wrap, or a clean kitchen towel. Place it in a warm spot in your kitchen (ideally between 70-78 F / 21-26 C).

8. Monitor for Activity: Watch for signs of activity. Your starter should begin to bubble, rise, and develop a pleasant, tangy aroma. This can take anywhere from 4 to 12 hours, depending on the warmth of your kitchen and the vigor of your starter. Once it has doubled in size and is very bubbly, it’s active and ready to use in your baking.