How to Make a Sourdough Starter From Scratch
A sourdough starter is the simplest thing in baking and the most intimidating. It's flour and water. That's it. You mix them together, leave them on your counter, and wait for wild yeast to show up. And it will, because yeast is everywhere. In the air, on your hands, on the flour itself.
I've been maintaining starters for years. I've killed a few, neglected a few, and brought more than one back from what looked like certain death. The truth is, sourdough starters are tougher than the internet wants you to believe. They don't need hourly feedings. They don't need bottled water. They don't need a $40 jar. They need flour, water, time, and a little patience.
This guide walks you through the whole process, day by day, from nothing to a bubbly, active starter that's ready to make bread, pizza, English muffins, and anything else you want to bake.
If you want great homemade bread and pizza but don't want to maintain a sourdough starter, our 72-Hour Pizza Dough Mix uses active dry yeast instead — just add water and you're making dough in minutes. But if you want to go the sourdough route, keep reading. It's worth it.
About the Author
Andris Lagsdin is the founder of Baking Steel. He invented the original Baking Steel in 2012 at his family's steel fabrication plant in Hanover, MA and has been teaching home bakers how to make incredible bread and pizza ever since. Andris teaches free live baking classes every week and recently launched the 72-Hour Pizza Dough Mix.
This starter method was developed by Ben Turcotte, a talented baker who worked with us at Baking Steel. Ben dialed in the ratios, the feeding schedule, and the day-by-day process. I've been using his method ever since and the guide below is how I walk people through it in my classes every week.
What Is a Sourdough Starter?
A sourdough starter is a living culture of wild yeast and bacteria that you grow from scratch using just flour and water. It's what gives sourdough bread its rise, its tang, and its complex flavor. No commercial yeast from a packet, just the natural microorganisms that exist all around us.
Some of the best bakeries and pizzerias in the country use natural leaveners instead of commercial yeast. The flavor is deeper, the texture is better, and the bread is easier to digest because the long fermentation breaks down gluten and complex sugars naturally.
Think of a sourdough starter like a tolerant houseplant. It doesn't need much, just occasional feeding with fresh flour and water. You can leave it in the fridge for weeks and it'll come back to life with a couple of feedings. I've neglected mine plenty of times. It always forgives me.
What You'll Need
Whole wheat flour we start with whole wheat because it has more nutrients than white flour, which gives the wild yeast more to feed on in those early days. Once your starter is established, you can switch to bread flour.
Bread flour - for daily feedings once the starter is active.
Water — room temperature. Tap water is fine in most places. If your tap water is heavily chlorinated, let it sit uncovered for an hour before using it or use filtered water.
A glass jar — a mason jar works perfectly. Something clear so you can watch the bubbles develop. A Weck jar is ideal because the lid sits loosely, but any glass jar with a lid you can leave cracked open works fine.
Time — about 10 days from start to an active, ready-to-bake starter. Hands-on time is about 5 minutes per day.
Day-by-Day Instructions
Day 1 — The Beginning
Mix 50g whole wheat flour and 60g room temperature water in your glass jar. Stir it until there are no dry spots. Leave the lid off or loosely covered for 4-6 hours at room temperature, then cover loosely and let it sit for another 16-18 hours.
Nothing exciting will happen yet. That's normal. You're just creating a hospitable environment for wild yeast to move in.
Day 2 — First Feeding
Add 50g bread flour and 50g water directly to the jar. Stir well. Cover loosely and let sit for 24 hours.
You might see a few small bubbles. Or you might not. Both are fine. Don't panic. The yeast is getting established.
Day 3 — First Discard and Feed
Now it starts. Discard about 100g of the starter, just scoop it out and toss it. Then add 50g bread flour and 50g water. Stir well. Cover loosely and let sit for 24 hours.
Discarding feels wasteful but it's necessary. You're keeping the culture manageable and giving the remaining yeast fresh food to consume. Without discarding, the starter gets too acidic and sluggish.
Days 4-8 — Repeat
Same routine every day: discard 100g, add 50g bread flour and 50g water. Stir. Cover loosely. Wait 24 hours.
Somewhere around day 4-5, you might notice a burst of activity, lots of bubbles, rising, maybe even a strong smell. Then it might go quiet again around day 6-7. This is completely normal. The bacterial population is shifting and the culture is finding its balance. Don't give up. Keep feeding.
By day 7-8, you should start seeing consistent rising and falling. The starter doubles in size within a few hours of feeding, then slowly falls back. It smells pleasantly tangy and yeasty, not like nail polish remover.
Days 9-10 — The Float Test
When your starter consistently doubles within 4-6 hours of feeding and smells nice and tangy, it's time to test it. Drop a small spoonful into a glass of water. If it floats, your starter is active and ready to bake with. If it sinks, give it another day or two of feedings.
Once it passes the float test, congratulations, you just created something alive from flour and water. Now you can make sourdough bread on a Baking Steel, sourdough pizza, sourdough English muffins, and anything else your heart desires.
Ready to bake? Grab a Baking Steel and make your first sourdough loaf →
How to Maintain Your Starter
If you bake regularly (a few times a week): Keep your starter on the counter and feed it daily. Use a small feeding ratio — 10g starter, 25g flour, 20g water. This keeps it active and ready to go without wasting a ton of flour.
If you bake occasionally (once a week or less): Keep your starter in the fridge. It goes dormant in the cold and only needs feeding once a week. When you want to bake, pull it out 24-48 hours before you need it, feed it twice, and it'll be back at full strength.
If you forget about it for weeks: Don't throw it out. Even a neglected starter with a layer of dark liquid on top (that's hooch, it's harmless) can be revived. Pour off the liquid, discard most of the starter, and feed it. It might take 2-3 feedings over a couple of days, but it'll come back. I've resurrected starters that looked completely dead. They're tougher than you think.
Troubleshooting — When Things Look Wrong
My starter isn't bubbling at all after day 3. Be patient. Some starters take longer depending on the environment, the flour, and the temperature of your kitchen. Cooler kitchens slow things down. If nothing is happening after day 5, try moving it to a warmer spot — on top of the fridge or near the oven (not inside it). Warmth accelerates fermentation.
My starter smells terrible. In the first few days, some off-putting smells are normal — the bacterial population is chaotic and sorting itself out. If it smells like nail polish remover (acetone), it's too acidic and hungry. Feed it more frequently, twice a day instead of once. The smell should improve within a day or two.
My starter rose like crazy on day 3 then went flat. Classic. This is called a "false rise" bacteria producing gas that looks like yeast activity. The real yeast population is still building. Keep feeding on schedule. It'll come back stronger around day 7-8. Everyone goes through this.
My starter has liquid on top. That's hooch, a byproduct of fermentation. It means your starter is hungry. Pour it off or stir it in, then feed immediately. Not a problem, just a signal that it needs food.
My starter isn't doubling. Could be a temperature issue (too cold), a flour issue (try switching to a different brand), or a hydration issue. Make sure you're measuring by weight, not volume. 50g of flour is always 50g. A "half cup" of flour can vary wildly.
My starter passed the float test but my bread didn't rise. The starter is fine, the issue is probably in the bread recipe. Make sure you're using the starter at peak activity (just after it doubles, before it starts falling). Timing matters. Check out our sourdough bread recipe for the full method with timing.
The No-Discard Method
A lot of people ask about making a sourdough starter without discarding. You can do it — instead of discarding and feeding, you just add a very small amount to a fresh jar of flour and water each day. The results are the same, you just use slightly more flour overall and it takes a bit longer. But if wasting food bothers you, it's a perfectly valid approach.
The key is keeping the ratio right, you always want the fresh flour to significantly outweigh the existing starter so the yeast has plenty to eat.
What to Bake First
Once your starter is active, the world opens up:
Sourdough bread on a Baking Steel — our 75% hydration recipe, open baked on steel with no Dutch oven. Incredible crust, open crumb, and the bottom crust will blow your mind.
Sourdough pizza — take your pizza game to a completely different level. The tang and complexity of sourdough pizza crust is something you can't replicate with commercial yeast.
English muffins — sourdough English muffins on the Baking Steel Griddle are life-changing. Nooks and crannies for days.
And if you love the long-fermentation approach but don't want to maintain a starter, our 72-Hour Pizza Dough Mix gives you the same slow-fermented flavor using active dry yeast. Just add water, wait, and bake. It's the bridge between convenience and craft.
Frequently Asked Questions
How long does it take to make a sourdough starter from scratch?
About 10 days from the first mix to an active, ready-to-bake starter. The hands-on time is about 5 minutes per day — just a quick discard and feed. By day 8-10, your starter should be consistently doubling within a few hours of feeding.
Can I make a sourdough starter without discarding?
Yes. Instead of discarding and feeding in the same jar, you can transfer a small amount of starter to a fresh jar with new flour and water each day. The results are the same — it just uses slightly more flour overall. The key is making sure the ratio of fresh flour to existing starter stays high so the yeast has plenty to eat.
What is a sourdough mother starter?
A sourdough mother starter is simply the original culture you maintain and feed over time. It's the "mother" that you pull from whenever you need starter for a recipe. You keep feeding the mother indefinitely — some bakers have maintained theirs for decades. Every time you bake, you take what you need from the mother and feed it back up.
Do you need sourdough starter to make sourdough bread?
Yes — sourdough bread by definition uses a natural sourdough starter instead of commercial yeast. The starter provides the rise and the signature tangy flavor. If you want great bread without maintaining a starter, our 72-Hour Pizza Dough Mix uses active dry yeast with a long cold fermentation that develops deep flavor — just a different path to great results.
Why is my sourdough starter not bubbling?
The most common reasons are temperature (too cold slows fermentation), flour (some flours perform better than others), or timing (some starters just take longer). Try moving it to a warmer spot, switching flour brands, or giving it a few more days. Most starters that seem dead just need more time and consistent feeding.
Can I use all-purpose flour for my sourdough starter?
You can, but bread flour works better because it has more protein and nutrients for the yeast to feed on. We recommend starting with whole wheat flour for the first day (even more nutrients), then switching to bread flour for daily feedings. All-purpose will work in a pinch — the starter will just take a little longer to get going.
How do I know when my sourdough starter is ready to use?
The float test is the simplest check. Drop a small spoonful of starter into a glass of room temperature water. If it floats, the starter has enough gas production to leaven bread and it's ready to bake with. You should also see consistent doubling within 4-6 hours of feeding and a pleasant, tangy aroma.
What is the best flour for sourdough starter?
Whole wheat or rye flour for the initial build because they have more natural nutrients and wild yeast. Once established, switch to bread flour for daily feedings — it gives the best balance of nutrition and performance. We use organic bread flour from Central Milling for everything we bake, including feeding our starters.
