The basics
A starter is just flour and water fermented by wild yeast and bacteria. Feeding it means giving it fresh flour and water so it keeps producing the gas that leavens bread.
Regular feeding (baking weekly or more)
- Discard all but ~20g of starter.
- Add 100g flour and 100g water.
- Leave at room temperature until doubled and bubbly (6–12 hours depending on temperature).
Storage feeding (baking rarely)
- Keep the starter in the fridge between bakes.
- Feed once a week, same ratios as above, then return to the fridge after a couple hours at room temperature.
- To wake it up before baking, feed it 1–2 times at room temperature over 24–48 hours until it’s reliably doubling.
Signs of a healthy starter
- Doubles in size within 6–8 hours of feeding at room temperature.
- Smells pleasantly sour/yeasty, not like acetone or mold.
- Visible bubbles throughout, not just on top.
If it’s sluggish, feed it more often for a few days before giving up on it.