One thing at a time
Here’s how.
- Day one: stir 50 g whole-grain flour and 50 g water in your jar. Cover loosely, not airtight. Mark the level and keep it somewhere comfortably warm, about 70–75°F.
- Day two: keep 50 g of the mixture. Stir in 50 g all-purpose flour and 50 g water. Loosely cover again. Throw away the rest of this young starter.
- From day three: repeat that feeding about every 12 hours. Keep 50 g starter, then add 50 g flour and 50 g water. Use a clean jar when the sides get crusty.
- Look for reliable growth, not one early burst of bubbles. It is ready when it doubles within about 4–8 hours after feeding, over several feeds, and smells pleasantly tangy. Some jars need two weeks or longer.
- To keep baking, feed it regularly. For a break, refrigerate a mature starter and feed about weekly. Before bread day, give it room-temperature feeds until it doubles reliably again.
A little more than the ingredients
Why it belongs in the house.
Flour and water become a living culture of wild yeast and lactic-acid bacteria. The yeast lifts your bread; the bacteria bring that familiar sourdough tang. A healthy starter makes that work possible without packaged yeast.
The jar is a beginning, not a spoonful of probiotics. Bake the finished dough before eating it. Once baked, the bread no longer contains the starter’s live culture.