After using your active sourdough starter for baking, instead of feeding it immediately, leave just a thin layer (about a teaspoon) in your jar. No need to add flour or water at this stage.
Two Options For Storage
Room Temperature (Short-Term): If you plan to use your starter within a few days, leave the jar at room temperature with a loose-fitting lid.
Refrigeration (Long-Term): For longer storage, place the jar in the refrigerator with a loose-fitting lid.
Reactivating Scrapings
When you’re ready to bake again, add equal amounts of flour and water. The amounts will depend on how much starter you need for your recipe.
Mix well and let the starter sit at room temperature until it becomes bubbly and active, usually 4–12 hours, depending on your home's temperature and the age of the scrappings.
Once the starter has doubled in size proceed with your chosen recipe.
Notes
Storage: You can leave the scrapings at room temperature for a few days or in the refrigerator for several weeks to a few months. The longer it sits, the longer it may take to reactivate.Tips
Always use clean utensils to avoid contamination.
Use Fresh Scrapings: Try not to leave the scrapings unused for more than 1–2 weeks in the fridge to prevent them from becoming too weak or moldy.
Start Small: Begin with equal parts flour and water, then scale up as needed in subsequent feedings.
Monitor Activity: The time it takes for the starter to become active depends on how fresh and healthy the scrapings are. If it seems sluggish, try a boost with whole wheat or rye flour.
Mark your container to track how much the starter rises after feeding.