Gather supplies: flour (whole wheat or rye), water (filtered or dechlorinated), clean jar (quart-size), spoon/spatula, rubber band or marker, breathable cover (lid loosely set or cheesecloth)
Day 1: Add 50 g flour + 50 g water to the jar; mix until no dry spots; cover loosely; mark level
Day 2: Discard about half (do not worry about exact amount); add 50 g flour + 50 g water; mix; cover; mark level
Day 3: Discard about half; add 50 g flour + 50 g water; mix; cover; mark level
Day 4: Discard about half; add 50 g flour + 50 g water; mix; cover; mark level
Day 5: Discard about half; add 50 g flour + 50 g water; mix; cover; mark level
Continue daily feedings (discard half, then add equal parts flour and water by weight) until you see consistent bubbling and reliable rise (typically 5–14 days)
When active: Feed 1:2:2 (starter:water:flour by weight) or 1:3:3 if it’s very active; keep at room temperature
To check readiness: Use when it reliably doubles in volume within 4–8 hours after feeding and shows lots of bubbles throughout
Maintain: Feed every 12–24 hours at room temperature, or refrigerate and feed weekly (bring to room temp and feed 1–2 times before baking)
If it’s sluggish: Switch to whole rye or whole wheat for 1–2 feedings and ensure water is not too cold; keep at ~24–27°C (75–80°F)
If it smells very unpleasant (but not pink/orange/black/green): Continue feeding; discard and refresh more frequently (every 12 hours) for 1–2 days
If you see pink/orange colors, fuzzy mold, or clear contamination: Discard and restart with fresh flour and water
For baking: Feed starter 4–12 hours before using so it peaks (doubles) and is full of bubbles