If baking every day, it’s best to leave your starter at room temperature and feed it every 8-12 hours. If only baking once in a while, store it in the fridge and feed once per week.
~1 tablespoon (15 grams) sourdough starter (compost the remainder)
~3 tablespoons (40 grams) warm water (filtered or de-chlorinated)
Stir all ingredients together until a smooth batter is formed. Adjust your flour & water ratio, if necessary, to get the consistency of smooth peanut butter. Pour into a wide mouth jar and cover with a loose lid or muslin cloth secured with a rubber band to hold it in place.
If baking intermittently, leave the starter out at room temperature for an hour after feeding, then refrigerate. The *day before* you want to use the starter in a recipe, remove it from the fridge and feed it every 8-12 hours. This rejuvenates the culture from it’s cold slumber, and gets it healthy and active for leavening.