Last updated: August 18, 2026
This sourdough starter recipe turns just flour and water into a living, bubbly culture strong enough to leaven your own bread at home.
You will find the full ingredient list and step-by-step method in the recipe card below, but read through this guide first so you understand what is happening at each stage.
What a Sourdough Starter Actually Is
A sourdough starter is a fermented mixture of flour and water that has captured wild yeast and lactic acid bacteria from the flour itself and the air around your kitchen.
Those organisms feed on the natural sugars in flour, releasing carbon dioxide and organic acids as they go.
The carbon dioxide is what makes bread rise, and the organic acids are what give sourdough its tang.
Unlike commercial yeast, which you buy in a packet, a starter is something you build and maintain over days, and it keeps working for as long as you feed it.
Ingredients for This Sourdough Starter Recipe
Flour
Whole wheat or rye flour gets a starter going faster than all-purpose because the extra bran and germ carry more wild yeast and more food for the bacteria.
Once your starter is active, you can switch it over to all-purpose or bread flour for daily feedings, or keep a portion whole grain if you like a more sour flavor.
King Arthur all-purpose flour is a reliable choice once you are past the first week, since its consistent protein content keeps fermentation predictable.
Water
Use filtered or dechlorinated water rather than water straight from a heavily chlorinated tap, since chlorine can slow down or kill the wild yeast you are trying to cultivate.
Room temperature water, around 70 to 75 degrees Fahrenheit, works best for activating the culture without stalling it.
Day-by-Day Method
Days 1 and 2: Mixing and Waiting
On day one, stir equal weights of flour and water together in a clean glass or plastic container until no dry flour remains, then cover loosely and let it sit at room temperature for 24 hours.
Do not feed it again during this first stretch, even if nothing seems to be happening, since the wild yeast population is still establishing itself.
By day two you may see a few small bubbles or smell something faintly fruity or like blue cheese, which is a normal part of the process and not a sign of failure.
Days 3 through 5: Daily Feedings
Starting on day three, discard all but a small amount of the starter and feed the remainder with fresh equal parts flour and water by weight.
Discarding matters here because it keeps the ratio of food to organisms balanced, so the culture does not run out of fuel and turn overly acidic between feedings.
Feed once every 24 hours at this stage, and mark the container’s side with a rubber band or piece of tape right after each feeding so you can track how much it rises.
You should start to see more consistent bubbling and a slightly domed surface by day four or five, along with a stronger, more yeasty smell replacing the earlier funky one.
Days 6 and 7: Building Strength
Once your starter reliably doubles in size within 6 to 8 hours of a feeding, it has enough strength to bake with, which typically happens by day six or seven.
Switch to twice-daily feedings if you notice it rising and falling faster than 8 hours, since a hungry starter that has already collapsed will not give your bread the lift you want.
A starter passes the float test when a small spoonful dropped into a glass of water floats instead of sinking, confirming it is gassy enough to use.
Maintaining Your Starter Long Term
Daily Feeding Schedule
If you plan to bake often, keep your starter at room temperature and feed it once or twice a day using equal weights of flour and water added to a small amount of retained starter.
This is the schedule that keeps the culture at peak activity and ready for same-day baking whenever you need it.
Refrigerator Storage
If you bake less frequently, store the starter in the refrigerator and feed it just once a week, pulling it out and letting it warm to room temperature for a couple of feedings before you bake with it again.
Refrigeration slows the yeast and bacteria down without killing them, so the starter can sit dormant for weeks without harm.
Substitutions and Variations
Rye flour makes an especially vigorous starter if you are struggling to get one going, since it is richer in the wild yeast and enzymes that kick off fermentation.
You can also maintain a gluten-free starter using a blend like brown rice and sorghum flour, though it will need slightly more frequent feedings since gluten-free flours ferment a bit faster.
Where This Method Comes From
Sourdough predates commercial yeast by thousands of years, with evidence of fermented grain doughs tracing back to ancient Egypt.
Before bakers’ yeast became widely available in the late 1800s, a starter passed down and maintained within a household or bakery was the only reliable way to leaven bread.
San Francisco became closely associated with the style in the mid-1800s, when Gold Rush-era bakers found the local wild yeast strains produced a particularly tangy loaf, though starters built anywhere will develop their own distinct flavor based on the local environment.
Ready to see exact quantities and timing at a glance? Use the recipe card below to keep every feeding on track.
Sourdough Starter
A simple flour-and-water sourdough starter built over seven days of feedings, ready to leaven your own homemade bread.
Ingredients
- 100g whole wheat or rye flour (for days 1-2)
- 100g water, room temperature (for days 1-2)
- 100g all-purpose flour (for daily feedings, days 3 onward)
- 100g water, room temperature (for daily feedings, days 3 onward)
Instructions
- In a clean glass or plastic container, stir together 100g whole wheat or rye flour and 100g room temperature water until no dry flour remains.
- Cover loosely and let sit at room temperature for 24 hours.
- On day 3, discard all but 50g of the starter, then stir in 100g all-purpose flour and 100g water.
- Cover loosely and let sit at room temperature for 24 hours, repeating this discard-and-feed step once daily through day 5.
- Mark the side of the container after each feeding to track rise, and watch for bubbling and a fruity or yeasty smell.
- On days 6 and 7, continue daily feedings and check that the starter doubles in size within 6 to 8 hours of a feeding.
- Test readiness with the float test: drop a small spoonful into a glass of water and confirm it floats.
- Once your starter doubles reliably and passes the float test, it is ready to use in any sourdough bread recipe.
Notes
If your starter is sluggish, move it somewhere warmer (78-82°F) and continue daily feedings; rye flour can help jumpstart a slow starter. Store in the refrigerator and feed weekly once established if not baking daily.
Nutrition Information:
Yield:
8Serving Size:
100gAmount Per Serving: Calories: 90Total Fat: 0gSaturated Fat: 0gSodium: 1mgCarbohydrates: 19gFiber: 1gSugar: 0gProtein: 3g
Sourdough Starter Recipe Questions
Why is my starter not bubbling after three days?
Kitchen temperature is the most common culprit, since wild yeast activity slows significantly below 70 degrees Fahrenheit.
Move the container somewhere warmer, like on top of the refrigerator or inside an oven with just the light on, and give it another day or two before troubleshooting further.
Can I use tap water for my starter?
You can, but only if you let it sit uncovered for a few hours first so the chlorine has time to evaporate, or use filtered water instead.
Heavily chloraminated municipal water does not evaporate its treatment chemicals as easily, so filtered water is the safer bet in that case.
What does the liquid on top of my starter mean?
That grayish liquid, often called hooch, simply means your starter is hungry and has run out of food since its last feeding.
Pour it off or stir it back in, then feed the starter right away to bring it back to full strength.
How much starter do I need to bake one loaf of bread?
Most home bread recipes call for somewhere between 100 and 200 grams of active starter, so keep that range in mind when deciding how much to build up before baking day.
Check your specific recipe’s ratio, since some artisan formulas use a smaller percentage of starter relative to the total flour weight.
Can I speed up the process?
You cannot rush the wild yeast population significantly, but starting with rye flour and keeping the container in a consistently warm spot, around 78 to 82 degrees Fahrenheit, gets you to an active starter a day or two faster than average.
Is it normal for my starter to smell like alcohol?
Yes, a boozy or acetone-like smell is common right before a feeding and simply signals the yeast has consumed most of the available sugars.
A fresh feeding will mellow that smell out within a few hours as the culture goes back to work.
Final Thoughts on This Sourdough Starter Recipe
Once you have worked through this sourdough starter recipe and built an active culture, you will have a renewable ingredient that can produce loaves, pancakes, and countless other bakes for years with nothing more than routine feedings.
Keep a consistent feeding rhythm and pay attention to how your particular starter behaves in your kitchen, and it will reward you with reliable, flavorful bread.
