Gather supplies: jar (quart-size or larger), lid or cover (not airtight), spoon or spatula, kitchen scale (optional but helpful), rubber band/marker, flour (unbleached all-purpose or bread flour) and water (filtered or dechlorinated if needed)
Day 1: Mix 50 g flour + 50 g water in a jar until no dry spots remain
Cover loosely (lid slightly ajar or breathable cover)
Leave at warm room temperature (about 70–80°F / 21–27°C) out of direct sunlight
Day 2: Discard about half (discard to keep starter from getting too large)
Feed with 50 g flour + 50 g water; mix until smooth
Mark starter level with a rubber band/marker
Day 3: Discard about half
Feed with 50 g flour + 50 g water; mix until smooth
Day 4: Discard about half
Feed with 50 g flour + 50 g water; mix until smooth
If you see bubbles and some rise, continue feeding daily; if not, feed twice daily (morning/evening) until active
When starter reliably doubles in size within 4–8 hours after feeding, it’s ready to use
To maintain: Feed 1:1:1 by weight (starter:flour:water) and keep at room temperature if baking daily, or refrigerate if baking less often
For weekly baking: Refrigerate after feeding; feed once per week (or at least every 7 days), then use once it becomes active again
Before baking: Feed 1–3 times until it doubles and looks bubbly (timing depends on temperature and your starter’s strength)