From scratch · Sourdough
Sourdough starter
Flour and water, fed daily until wild yeast and bacteria make it bubble and rise: then keep it in the refrigerator for years.
✋ 1 hr 20 min hands-on
⏱ 14 days 1 hr start to finish
🍽 A jar of active starter; you keep about 50 to 100 g and feed it.
ContainsWheat.
Ingredients
- 1300 g all-purpose flour, about 100 g a day for 2 weeks
- 5½ cup water, about 100 g a day
Time
Hands-on time is when you’re busy; the rest is rising, simmering, chilling or cooling, when you can do something else.
| Step | Hands-on | Waiting |
|---|---|---|
| Mix the first batch | 5 min | 1 day |
| Feed daily, then twice a day, until it doubles in 4 to 6 hours | 1 hr 15 min | 13 days |
| In all | 1 hr 20 min | 14 days |
How long it keeps
- Refrigerator: keep it in a covered glass jar and feed it once a week (Clemson Extension; University of Alaska Extension). Metal containers and spoons aren’t recommended, since the acid can react with the metal (University of Alaska).
Nutrition
Estimated from the ingredients’ USDA FoodData Central numbers.
Steps
You’ll need: clean glass jar (1 quart) with a loose lid, kitchen scale, spoon (not metal is best), rubber band to mark the level.
- Day 1: stir 100 g flour and 100 g lukewarm water in the jar into a thick batter. Cover loosely and leave it in a warm spot for 24 hours.
- Day 2: stir it, then keep only 50 g and throw out the rest. Feed it 50 g flour and 50 g water, stir, and mark the level with a rubber band.
- Keep feeding once a day the same way (equal weights of starter, flour and water: 1:1:1). When it starts bubbling and smelling yeasty, after about 3 days, feed it twice a day, about every 12 hours.
- It’s ready to bake with when it doubles within 4 to 6 hours after a feeding, is bubbly all through, and smells pleasantly sour. That usually takes about 2 weeks (Clemson Extension).
- Keeping it: store it in the refrigerator in a clean glass jar with a loose lid, and feed it once a week (Clemson, University of Alaska). Before baking, take it out, feed it, and let it double.
- Gray liquid on top is normal (it’s called hooch): stir it back in for a more sour starter, or pour it off.
- Throw it out and start over if it turns green (University of Alaska), grows fuzzy mold, or smells rotten rather than sour. When in doubt, throw it out.
- Use the starter you remove at each feeding (the discard) in pancakes, waffles or crackers, or throw it away.
⚖️ ScalingKeep a small amount (50 to 100 g) and feed it 1:1:1 by weight. To build up starter for baking, feed it 6 to 12 hours before you mix the dough: for example 20 g starter, 50 g flour, 50 g water.
🛡 SafetyUse a clean jar, and don’t add baking soda to the starter itself (University of Alaska).
📜 The old wayIn Alaska, “sourdough” also means an old-timer: miners, trappers and homesteaders kept starters going because bread couldn’t be made without them, and supplies came by ship only once or twice a year (University of Alaska Extension).
Sources
- How to Make, Feed, and Bake With a Sourdough Starter: Sourdough 101 Guide, Clemson Cooperative Extension, Home & Garden Information Center, 2025. Accessed 2026-10-25.
- Sourdough (FNH-00061), University of Alaska Fairbanks Cooperative Extension Service, 2024. Accessed 2026-10-25.
- Can This Sourdough Starter Be Saved? Or Is This Starter a Goner?, UC Agriculture and Natural Resources, Master Food Preservers of San Luis Obispo and Santa Barbara Counties, 2020. Accessed 2026-10-25.