The idea of sourdough is that you keep it on the counter, use it, refresh it, and bake every day. But we don't all do that.
When to refresh?
If you use your sourdough starter for something
- add flour and water as below to bring it back to its original volume
If your starter has ben on the counter for more than a day, or in the fridge for more than a week
- discard all but two tablespoons (or so, you don't have to be exact) and
- add flour and water as below to bring it back to its original volume
If you let it go many weeks in the fridge or on the counter, and it has a layer of watery "hooch" on top, it will have kinda gone to sleep. You will need to refresh it a couple times to get it back to its most active state.
- drain off the hooch
- discard all bt 2 tablespoons (or use it as flavour in regular bread) and
- refresh as below, every day, keeping the starter on the counter, not in the fridge, for five or six days before it’s back to its original vigour.
What Flour?
I use organic whole wheat flour. Organic whole white flour should be OK too.
How To Refresh
[[Neal_Bowers?|Neal]] weighs his water and flour in to his starter (50g each); I use volume measures, I don't think it matters much. He ends up with a higher flour:water ratio so his starter is thicker.
- Discard all but a couple tablespoons.
- add ¼c flour
- add ¼c warm (body temperature - 100°F or 40°C) water
- stir and scrape down the sides and mix until absolutely 100% thoroughly mixed
- If you're going to use the sourdough tomorrow, leave it on the counter.
- Otherwise put it it in the fridge. The warm water you use will let the sourdough grow as it cools in the fridge.