Many recipes will tell you to feed your sourdough starter with equal parts starter, flour, and water. But if you start with too much starter, your bread can be overly sour from the lactic acid in the old sourdough starter. Starters should be fed once a week (whether you bake with them or not) and stored in the fridge in between feedings. Follow the simple instructions below to feed your sourdough starter for a mild-tasting bread.