Two Methods for Feeding and Maintaining an Established Starter:
At room temperature...
Unless your kitchen has huge temperature swings that make you feel like you're experiencing all of the seasons on any given day, room temperature counters provide a nice cozy spot for sourdough bacteria to grow.
However, choosing this method also requires that your sourdough starter be fed everyday. (Don't worry, if for some reason you miss a feeding, just pick up where you left off. Miss more than one day? I would start over, but that's me.)
When you are on a daily feeding schedule you need to stir the starter well and discard all but about 1/2 cup (4 oz weighed). To the remaining 1/2 cup (4 oz) add 1/2 cup warm water (8 oz of 80 degree F water) and 1 cup (8 oz) unbleached all-purpose flour.
When preparing to bake with the starter, the day before bake day feed the starter twice - at least 6 hours between feedings.
Then on bake day, feed the starter once at least 6 hours prior to baking.
Feed the remaining starter to continue your sourdough starter on the desired maintenance schedule.
In the fridge...
Plan on feeding the starter at least once a week.
Prior to feeding, pull the starter out of the fridge at least two hours prior to ensure the starter has time to come to room temperature.
If you are only feeding the starter - and not planning on baking yet - discard all but 1/2 cup (4 oz) and add 1 cup (8 oz) water and 2 cups (16 oz) unbleached all-purpose flour. Mix until smooth and cover, allowing the mix to remain at room temperature at least two hours before returning it to the fridge.
Wanna bake some bread??
3 days before you want to bake, take the starter out of the fridge to reactivate. Allow the starter to come to room temperature and plan on:
* day 1 - feed once, 1/2 cup (4 oz) warm water & 1 cup (8 oz) AP flour
* day 2 - feed twice - at least 6 hours apart, 1/2 cup (4 oz) warm water & 1 cup (8 oz) AP flour both times
* day 3 - feed once - 6 hours prior to baking, 1/2 cup (4 oz) warm water & 1 cup (8 oz) AP flour
Create Your Own Sourdough Starter:
Baking Sourdough Bread: