Building and Maintaining a Sourdough Starter
A sourdough starter is the engine of sourdough bread. Unlike commercial yeast, which is a single strain added to dough, a starter is a symbiotic culture that lives in your kitchen. It's slower than commercial yeast, but it builds flavor, improves digestibility through fermentation, and gives you complete control over your bread.
Patience and consistency are the only real requirements.
You don't need special equipment or ingredients—just flour, water, and a clean jar. The culture will establish itself if you feed it on a schedule and give it time. Discard seems wasteful at first, but it's how you maintain the right ratio of microbes to food.
- 1-quart glass jar or container with loose lid
- kitchen scale (optional but helpful)
- rubber spatula or wooden spoon
What goes in.
- —All-purpose or bread flour
- —Filtered or dechlorinated water (room temperature)
Feed, discard, repeat until it rises predictably
A starter is a ratio problem, not a formula. You're feeding wild yeast and bacteria so they outcompete other microbes and stay vigorous. Discard half the mixture before each feeding so you're not just growing an ever-larger jar of weak culture. Once your starter reliably doubles between feedings, it's ready to bake with.
The method.
Day 1: Mix flour and water
In a clean 1-quart jar, combine 50g flour (any kind works, but all-purpose or bread flour is standard) and 50g water at room temperature. Stir until no dry flour remains. The mixture will be thick, not pourable. Cover loosely—you want gas to escape and oxygen to reach the culture. Leave it on the counter at room temperature, away from direct sunlight.
Days 2–3: Feed without discarding
Each morning and evening (roughly 12 hours apart), add 50g flour and 50g water to the jar. Stir well, then cover loosely. You may see no activity for the first day or two. You may also see some liquid on top (hooch)—that's alcohol produced by yeast. You can stir it back in or pour it off; either way is fine. Smell it. You're looking for a sour, slightly yogurt-like aroma.
Days 4–5: Start discarding
Once you see bubbles forming or the mixture is more active (it will look slightly foamy and smell distinctly sour), you're ready to discard. Before each feeding, remove and discard half the starter—about 100g. Then feed with 50g flour and 50g water. Repeat twice daily. The jar will be messier and more vigorous now.
Days 6–7: Look for the double
Continue the discard-and-feed routine twice daily. You're waiting for the moment when the starter rises to roughly double its height between feedings, then peaks and starts to deflate slightly. This rise-and-fall cycle means the yeast and bacteria are strong enough and numerous enough to consistently ferment the food you're giving them. Once you see this happen at least twice in a row (morning and evening, or two consecutive days), your starter is ready to bake with.
Ongoing maintenance: Choose your rhythm
If you bake bread 1–2 times per week, keep your starter in the fridge and feed it once per week (take it out, discard half, add 50g flour and 50g water, let it sit on the counter for an hour, then refrigerate). If you bake multiple times per week or daily, keep it on the counter and feed it once or twice daily. Before you bake, take the starter out, let it reach room temperature, and feed it so it's at peak activity (doubled) when you mix your dough—usually 4–8 hours after feeding, depending on warmth.
Other turns to take.
Whole wheat or rye starter
Whole wheat and rye flours ferment faster and more vigorously than all-purpose flour. Your starter will be ready 1–2 days sooner and will rise more dramatically between feedings. The flavor will be deeper. Use the same 1:1:1 ratio (starter:flour:water by weight) but expect more activity.
Slower establishment (cooler location)
If your kitchen is cool (below 70°F), the culture will establish more slowly—7–10 days instead of 5–7. Feed it the same way, but be patient. Cold slows fermentation. You can speed it up by keeping the jar in a slightly warmer spot, like the top of the refrigerator or near (not on) a heat source.
Backup or secondary starter
Once your main starter is established, you can start a second jar with a spoonful of the first. It will establish faster because you're inoculating it with an active culture. Feed it normally and it will be ready in 2–3 days. This is useful if you travel or if you want to keep different flours or hydration levels on hand.
When it doesn't go to plan.
Use filtered or dechlorinated water if possible. Chlorine can inhibit the wild microbes you're trying to cultivate. (Letting tap water sit uncovered overnight will let chlorine evaporate.)
Markings on the jar help. Use a marker or rubber band to note the starting level on Days 1 and 2, so you can clearly see when the starter doubles.
If mold appears (pink, orange, or fuzzy growth), discard the entire starter and begin again. This is rare, but it means something contaminated the jar. Mold is different from hooch (liquid on top) or a brown crust on the sides—those are normal.
If nothing happens for a week, the flour or water may be the issue. Try filtered water and a different bag of flour. Wild yeast is everywhere, but some conditions inhibit it.
Once established, your starter is very forgiving. You can neglect it for weeks in the fridge. If it develops a dark liquid on top (hooch), that's fine—stir it in or pour it off. Feed it once before using it to bake.
Consistency by weight (a scale) is easier than by spoon, but spoons work fine once you develop a feel. A heaping teaspoon of starter, a heaping teaspoon of flour, and a heaping teaspoon of water is roughly the 1:1:1 ratio.
The ones that keep coming up.
How long does it take to establish a starter?
5–7 days in a warm kitchen (70–75°F). Cooler environments may take 7–10 days. You'll see activity (bubbles, rise) within 2–3 days, but consistency and strength take a few more feedings.
Can I use whole wheat flour instead of all-purpose?
Yes. Whole wheat establishes faster and rises more vigorously. You can also mix flours—50g all-purpose and 50g whole wheat, for example. The ratio and process are the same.
What's the hooch on top of my starter?
It's alcohol and liquid produced by fermentation. Stir it back in (it adds flavor) or pour it off (it won't hurt). Both are fine. If there's a thick layer and the starter smells boozy, you've gone too long between feedings—feed it more often.
My starter smells like nail polish remover or acetone. Is it ruined?
No. That's normal, especially early on. It's the smell of yeast and bacteria working. Once you establish a regular feeding schedule, the aroma will become more pleasantly sour and less chemical.
Can I reduce the discarding step?
Not without consequences. Discarding (reducing the culture before each feeding) keeps the ratio of microbes to available food in the sweet spot. If you never discard, the culture becomes weak and slow. You're not wasting it—you're managing it.
How do I know when my starter is ready to bake?
When it reliably doubles between feedings and you can see clear bubbles throughout. At room temperature, this usually takes 4–8 hours after feeding. Before you bake, feed your starter, let it rise until it's peaked (doubled and starting to recede), then use it. Timing depends on warmth, so observe your starter, not the clock.
Can I store my starter in the fridge?
Yes. Once established, refrigerate it and feed it once per week. The cold slows fermentation dramatically, preserving the culture. Before you bake, remove it, let it come to room temperature, feed it, and let it rise at room temperature (usually 4–8 hours) until it peaks.
What if I forget to feed my starter for weeks?
It can survive months in the fridge in a dormant state. When you're ready to use it again, feed it, let it rise, then feed it once or twice more before baking. It may take a feeding or two to regain full strength, but it will come back.
Do I need special equipment?
No. A clean jar, flour, and water are all you need. A kitchen scale makes feeding easier and more consistent (weighing is faster and more accurate than spooning), but spoons work fine.
Can I start a starter from scratch or do I need someone to give me one?
You can start entirely from scratch. Wild yeast and bacteria are already present in flour and your environment. Mix flour and water, feed it regularly, and the culture will establish itself. You don't need a 'starter' starter.