A sourdough starter is the most low-tech leavening system in baking, and once it is alive it produces bread that commercial yeast cannot match: deeply flavored, with complex acidity, and the open crumb structure that defines artisan loaves. The starter is also the most intimidating part of sourdough for new bakers, because the seven-day creation looks like nothing is happening for days at a time, and the rules around feeding seem to vary by source. The reality is that creating and maintaining a starter is simpler than most online guides make it sound. The microorganisms want to live, and the work is mostly about staying out of their way.
A sourdough starter is a fermented mixture of flour and water that hosts a stable colony of wild yeasts (mostly Saccharomyces and Candida species) and lactic acid bacteria (mostly Lactobacillus). The yeasts produce carbon dioxide for rise. The bacteria produce lactic and acetic acids for flavor. Together they outcompete other microbes once the culture is established, which is why a mature starter is remarkably stable and not prone to spoiling.
The seven-day creation
What you need: a clean glass or plastic jar (about 1 quart capacity), whole grain rye or whole wheat flour for the first few days, bread flour or all-purpose for ongoing feeding, filtered or non-chlorinated water (chlorine kills yeast), a kitchen scale.
Day 1: combine 50 grams whole grain flour and 50 grams water in the jar. Stir until no dry pockets remain. Cover loosely (a lid resting on top, or a cloth and rubber band). Leave at room temperature (70 to 78 F) for 24 hours.
Day 2: look for any bubbles. Likely there will be some. Discard about half the starter (this seems wasteful and is necessary). Add 50 grams flour and 50 grams water to what remains. Stir, cover, leave 24 hours.
Day 3: more bubbles, possibly significant rise. The smell may be sweet, slightly sour, or vaguely fruity. Discard half, feed with 50 grams flour and 50 grams water.
Day 4 to 5: this is the deceptive lull. The bubbles slow down, sometimes dramatically. New bakers think the starter died. It did not. The early bacteria (Leuconostoc) that produced the day 2 to 3 bubbles are dying off, and the actual sourdough microorganisms are building up. Continue feeding once daily, discarding half each time.
Day 6 to 7: vigorous activity returns. The starter rises and falls predictably between feedings, doubles or triples in volume within 6 to 8 hours, and develops a clean tangy smell. Transition to bread flour or all-purpose flour at this point. Switch to feeding twice a day (every 12 hours) for the last 24 to 48 hours before baking.
By day 7 to 10, the starter is usually ready to leaven bread. Test by floating a spoonful in water: at peak activity it floats. If it sinks, give it more time or more feedings.
Feeding ratios
The standard maintenance feeding is 1:1:1 by weight (starter:flour:water). So 30 grams starter plus 30 grams flour plus 30 grams water makes 90 grams total. After 8 to 12 hours at room temperature, the new mixture peaks and is ready to use or feed again.
For slower fermentation or longer hold times between feedings, use higher ratios:
1:2:2 produces peak at 10 to 14 hours.
1:5:5 produces peak at 14 to 18 hours.
1:10:10 produces peak at 18 to 24 hours.
These higher ratios are useful when you want to bake on a schedule that does not match the starter’s natural 8 to 12 hour cycle, or when the starter is sluggish and needs more fresh food.
The math is consistent: more flour and water relative to starter means more food and a longer rise. The peak point shifts later as the ratio increases.
Storing the starter
For a baker who uses the starter weekly or less:
Keep the starter in the refrigerator. Feed once a week (discard most, then 1:1:1 feeding, sit at room temperature 2 hours, return to fridge).
Bring out the night before baking. Two refreshments (12 hours apart) at room temperature wake it fully and have it peak when you need it.
For a daily or near-daily baker:
Keep the starter at room temperature. Feed every 12 hours.
For very long-term storage (months to years):
Spread some active starter thinly on parchment paper. Dry at room temperature for 2 to 4 days until brittle. Crumble into a jar. Store at room temperature in a cool dry place. To revive, mix 1 tablespoon of dried flakes with 30 grams water and 30 grams flour. After 24 hours, begin normal feeding. Full reactivation takes about 3 to 5 days.
Freezing also works. Place a tablespoon of active starter in a small freezer bag. Freeze. To revive, thaw at room temperature and begin feeding.
Reading the starter
Volume. A healthy starter doubles or triples between feedings. If it only rises slightly, it needs more frequent feeding or a warmer spot.
Bubbles. Lots of bubbles throughout the volume, not just on top. Surface bubbles only indicate sluggish activity.
Smell. Clean and tangy, like plain yogurt, kefir, apple cider, or sourdough bread. Funky smells (paint, nail polish, vomit, very sharp acetone) indicate either a struggling starter that needs more frequent feeding or contamination.
Texture. Loose and pourable when active. Stiff or rubbery means too thick or under-fermented.
Hooch. A layer of clear amber to gray liquid on top after long intervals between feedings. This is alcohol produced by the yeast. Not dangerous, but a sign the starter is hungry. Pour off or stir back in (stirring back in produces a tangier flavor profile).
Troubleshooting
Starter not rising at all by day 7
The culture is establishing slowly, possibly due to cool temperatures or low-microbe flour. Move to a warmer spot (the top of the refrigerator, or near a baking oven if convenient). Switch back to whole grain flour for 2 to 3 feedings. Wait. Most starters that look dead at day 7 wake up by day 10 to 12.
Pink, orange, or fuzzy growth
This is contamination by mold or other bacteria. Throw out the starter, clean the jar with very hot soapy water, and restart. This is rare but unmistakable. Healthy starter is never pink, orange, blue, green, or fuzzy.
Strong vinegar or acetone smell
The starter is hungry. The acid balance has tilted toward acetic acid (the same as in vinegar) and ethanol. Feed more frequently with a higher ratio (1:5:5 instead of 1:1:1) and the smell should normalize within 2 to 3 feedings.
Hooch every day
The starter is consistently outpacing its food supply. Either feed more often, increase the ratio, or move to a cooler location.
Starter rises and then collapses very quickly
The starter is hungry or too warm. Either feed sooner after the peak (instead of waiting until it falls), or use a higher feeding ratio.
Bread doesn’t rise enough
The starter is not at peak when used. Test with the float test before adding to dough. If the spoonful sinks, wait or feed and try again in 4 to 6 hours.
Maintenance rhythms
A weekly baker’s rhythm:
Friday morning: take starter from fridge, discard most, feed 1:5:5, sit at room temperature.
Friday evening: feed again 1:1:1.
Saturday morning: starter peaks, use for the levain (the starter portion in a specific recipe).
Saturday evening: feed the remaining starter, return to fridge for the week.
A daily baker’s rhythm:
Morning: feed 1:1:1, leave at room temperature.
Evening: starter peaks, use whatever portion is needed for that day’s dough. Feed the remainder.
Both rhythms work indefinitely. Starters that are decades old (King Arthur’s commercial starter, for instance, traces to the early 1900s) are still living cultures that have been fed continuously. The culture in your jar is no different in principle.
Once a starter is established, the bread possibilities open up. Open-crumb country loaves, focaccia, pizza dough, baguettes, English muffins, pancakes, crackers, and even cake all use the same starter as a base. The seven-day investment pays off for years.
Frequently asked questions
How long does it take to create a sourdough starter from scratch?+
Seven to fourteen days. Most starters show vigorous activity around day 5 to 7, but some take up to two weeks depending on flour, water, and ambient temperature. Day 2 to 4 is the deceptive phase: lots of bubbles from non-yeast bacteria that die off, followed by an apparent slowdown before the actual yeast population builds up. Wild yeast and lactic acid bacteria together produce the leavening and flavor.
What flour is best for starting a sourdough?+
Whole grain rye or whole wheat flour for the first 3 to 4 days, then transition to bread flour or all-purpose. Whole grain flour contains more wild yeast and bacteria on the bran, which jumpstarts the culture. After the starter is established, plain bread flour works fine for maintenance. Organic and stone-milled flours often produce more vigorous starters because they retain more microorganisms than highly processed flour.
How often should I feed a sourdough starter?+
Active starter at room temperature: every 12 hours when very active, every 24 hours otherwise. Starter in the refrigerator: once a week is sufficient. The feeding ratio is typically 1:1:1 by weight (starter:flour:water), so 30 grams starter plus 30 grams flour plus 30 grams water. For sluggish starters or just before baking, increase to 1:2:2 or 1:5:5 to give the yeast more food and shorter time to peak.
What does a healthy sourdough starter look like?+
A healthy starter doubles or triples in volume within 4 to 8 hours of feeding, shows lots of bubbles throughout (not just on top), has a clean tangy smell (like yogurt or apple cider, not paint or nail polish), and passes the float test (a small spoonful floats in water at peak activity). The texture should be loose and pourable, not stiff. Color is creamy off-white to pale tan, sometimes with a clear amber liquid (hooch) on top if it has gone too long without feeding.
Can I store a sourdough starter long-term?+
Yes. The refrigerator slows the culture to weekly feeding maintenance. Beyond that, dry the starter (spread thin on parchment, dry until brittle, store in a jar at room temperature) or freeze a portion. Dried starter rehydrates after a few warm feedings. Frozen starter takes 2 to 3 days of feeding to fully reactivate. Both methods preserve the original yeast culture and let you bake again after months or years of dormancy.
Priya Sharma
Priya Sharma writes for The Tested Hub.