How to Make Sourdough Starter
This guide shows exactly how to make a sourdough starter from scratch. Once you understand the process, it’s simple, and it just takes a little time and patience. If you’re troubleshooting, check out my Sourdough Bread Troubleshooting Guide or my post on maintaining a sourdough starter.
A sourdough starter
A sourdough starter is the foundation of homemade sourdough bread, English muffins, and rolls. It’s a living mixture of wild yeast and bacteria that feed on flour and water. Over time, they form a healthy colony that makes your bread rise without any commercial yeast.
When you first create a starter, you encourage these wild organisms to grow by giving them fresh flour and water every day. Once established, the wild yeast produces carbon dioxide that lifts your dough, while the natural bacteria add that signature tangy flavour.
The bacteria, mainly lactobacilli, produce lactic and acetic acids. This is what gives sourdough its sour flavour.
What you need
Every starter develops a little differently depending on your room temperature, humidity, and even the flour you use.
You’ll need:
- Flour
- Water
- A kitchen scale
It’s best to measure by weight for consistency.
Choosing the flour
Any grain-based flour can work, but unbleached all-purpose or bread flour gives the most consistent results. Rye and whole wheat can be used too, though rye tends to ferment faster because it contains more natural sugars and enzymes.
Rye flour often makes a starter look active early on, but that early bubbling can be misleading. It’s mostly bacterial activity before the yeast really establishes itself. Even if your starter looks bubbly after a day or two, it’s still too young to bake with. A white flour starter can later be used to bake whole grain or rye breads, so it’s a good all-purpose base.
Choosing the water
If your tap water is heavily chlorinated, it can slow fermentation. Filtered water, or tap water that has been boiled and cooled, works best.
Personally, I just use tap water. Mine doesn’t affect my starter or other ferments. If you’re unsure about yours, filtered water is a safe choice.
The best temperature for a sourdough starter
Yeast and bacteria grow best at around 21-26 °C (70-79 °F). If it’s too cold, the process slows right down. In very warm conditions, it will speed up, and your starter may need more frequent feeds.
Cooler temperature tip:
Pop your starter in a cooler bag with a jar of hot water beside it and close the bag to keep the warmth in. It’s a great little warm space for cold winter days. A yoghurt maker also works well. Fill it with a little bit of hot water (making sure it doesn’t touch the starter jar or it can get too hot) and set the starter jar inside so it stays gently warm.
Day-by-day sourdough starter guide
Day 1
- The following uses 30 g flour and 30 g water as a base.
Note: I always mix the flour, water, and starter in a separate bowl first, then scrape the smooth mixture into a clean jar. It keeps the jar tidy and makes level markers easy to see. Old starter sticks like glue, so this saves a lot of scrubbing.
- Mix flour and water in a bowl until combined.
- Put in a clean jar and cover with a balanced lid or cloth.
Day 2
- Tip the starter into a bowl, add 30 g flour and 30 g water, and mix until smooth. Then transfer it to a clean jar.
Day 3
- You might notice bubbles forming after day 2, but this early activity comes from bacteria, not yeast. It’s a good sign that fermentation has started, but your starter still needs more time before it’s ready to bake with.
- Pour 30 g of your starter mixture into a new bowl, feed it 30 g of flour and 30 g of water, mix well, then transfer it to a clean jar. Mark the level with a rubber band so you can see how much it rises. Discard the rest.
Days 4–10:
Repeat the same feeding each day: take 30 g of starter, feed it 30 g flour and 30 g water, and move it to a clean jar. Continue discarding the excess.
By day 4 or 5, you should see more bubbles or smell a mild tang. That’s a good sign, though it’s still not ready for bread. You can use some of the discard for recipes like pancakes or cookies.
Discarding is important. It keeps the yeast and bacteria balanced by giving them enough food each time you feed. If you keep feeding the entire jar, it compounds quickly and you’ll burn through a lot of flour.
Keep only a small portion (about 30 g) and feed that each day. Save the rest of your discard in a container for sourdough discard recipes.
Things to watch for
If your starter becomes runny, it’s usually because of the acid and alcohol produced by the bacteria and yeast. That’s normal. Just keep feeding it.
If liquid forms on top or underneath, it’s a sign your starter is hungry. Check the temperature. If it’s too hot, fermentation speeds up. Feed more often, every 12 hours if needed, until it settles.
Feeding ratio
While building your starter, use a 1:1:1 ratio which is equal parts starter, flour, and water by weight. Measuring by weight keeps your starter consistent, as water weighs more than flour.
If your starter is doubling within 6 hours by day 6 or 7, it’s nearly ready. Keep feeding 1:1:1 twice daily until it becomes strong and predictable.
Testing your starter’s strength
To check if your starter is ready to bake with, it should double after feeding it at 1:1:1 within about 4-5 hours at room temperature, 21-26 °C (70-79 °F).
You can also test it by feeding it a higher ratio, like 1:2:2 (one part starter, two parts flour, two parts water). If it can double or triple within 6 hours, it’s strong enough to raise a loaf.
If it’s still slow, keep feeding twice daily for a few more days and test again.
Maintaining your new starter
Once your starter is active and reliable, regular maintenance keeps it strong. Feed it often enough to avoid acid build-up. If you’re keeping it at room temperature, feed 2-3 times a day at 1:1:1, or twice a day at 1:2:2. In warmer weather, you may need to feed more frequently.
When it peaks (meaning it has doubled and just before it starts to fall) that’s when it’s best to use it for baking.
Once it’s well established, you can store it in the fridge. For more details, see my full guide on how to maintain a sourdough starter.
Sourdough starter troubleshooting FAQs
Chances are it was the lactobacillus bacteria in your starter forming those bubbles, and not the yeasts. Bacteria also create bubbles while they are converting sugars to lactic and acetic acid, but it’s the yeasts in the starter that will give rise to your bread. The yeast colony takes a little longer to establish itself. Be patient and keep feeding and refreshing your starter
Be patient and keep regularly feeding your starter and ensure it’s in a warm spot. If you’ve been feeding your starter for at least 6 days and it’s not bubbling you could experiment with an extra feeding, or check your water source and that it’s not hindering the starter.
This is a sign that your starter is hungry. Your starter might be fermenting a little too fast and the yeasts have run out of food. This can happen if the room your starter is in is too hot.
Check the temperature and fix it if it’s too hot before continuing. Then, carry on with the 1:1:1 feeds, but you can switch to 12 hourly feeds if it keeps splitting.
It is normal for a starter to rise, reach its peak, and collapse once it has run out of food. Once your starter can double within 5-6 hours after being fed 1:1:1, switch to 12 hourly feedings.
If it doubles within 4-5 hours with the increased feedings, try the starter activeness test.
Has the temperature changed? If it’s colder your starter will take longer to double. Have you increased the feedings? If you increase the feeds before the starter is ready, it will slow things down a bit.
If you keep up with regular discarding and feeding, in a fresh jar each time, your lactobacillus colony will thrive. As they do, the amount of lactic acid they produce will inhibit mould growth and harmful bacteria.
A contaminated sourdough starter is pretty rare. If you do see mould growing on your starter or it develops a pink, red, or orange tinge, discard it and start again.
Sourdough Starter Recipe
Ingredients
- Unbleached all-purpose flour
- Water*
Instructions
Day 1
- Combine 30 g flour and 30 g water in a bowl and mix very well until smooth. Transfer the mixture to a clean glass jar, cover it with a loose lid or cloth, and leave it in a warm spot around 21-26 °C (70-79 °F) out of direct sunlight.
Day 2
- Tip the starter into a bowl, add 30 g flour and 30 g water, and mix well until smooth. Scrape the mixture into a clean jar. Mixing in a bowl first keeps the jar tidy, since old starter sticks like glue.
Day 3
- Pour 30 g of your starter into a bowl, add 30 g of flour and 30 g of water (a 1:1:1 ratio), and mix well. Transfer it to a clean jar and discard the rest. You might notice some small bubbles by now but these come from bacteria starting to ferment, not yeast just yet.
Day 4
- Pour 30 g of the starter into a bowl, feed it 30 g of flour and 30 g of water, and mix until smooth. Transfer to a clean jar and discard the rest. By this stage, your starter might be bubbling more and smell slightly sour.
Days 5-10
- Each day, pour 30 g of the starter into a bowl, feed it 30 g of flour and 30 g of water, mix well, and transfer it to a clean jar. Discard the rest.
- If your starter is doubling easily within about 4-6 hours of feeding start feeding it 1:1:1 twice a day instead of once, or switch to a higher ratio like 1:2:2 or 1:3:3 once a day. If it’s runny each time you go to feed it, that means it’s getting too hungry between feeds. Increase the ratio or feed twice per day.
Ready for baking
- By around day 10, your starter might be ready to bake with, though sometimes it happens sooner. You’ll know it’s ready when it doubles within 4-6 hours at a 1:1:1 feeding, has a domed top, and is bubbly, spongy, and pleasantly yeasty.
- If you’re feeding it at a higher ratio, like 1:2:2 or 1:3:3, the rise will take longer, usually around 6-10 hours depending on your room temperature. That’s completely normal. The extra flour and water give the yeast more food, so the starter needs more time to ferment and reach its peak.
- If it’s still slow or inconsistent after that, keep feeding daily until it rises and falls predictably after each feed. A strong starter will show a clear rhythm and bounce back quickly after every feeding.
- If it’s still slow or inconsistent after that, keep feeding daily until it rises and falls predictably after each feed. A strong starter will show a clear rhythm and bounce back quickly after every feeding.
Notes
Troubleshooting tips
- No bubbles yet? Be patient. Early activity is usually from bacteria, not yeast. Keep feeding daily, and it will become active.
- Runny or watery starter, or grey liquid (hooch) on top: It’s hungry. Feed more often or increase the ratio (1:2:2 or 1:3:3) so it has more food.
- Strong, vinegary smell: Too much acid build-up. Give it a couple of good feeds at room temperature to rebalance it.
- Slow to rise: Check your room temperature. Starters like it warm (but not too hot), around 21–26 °C (70–79 °F).
Hi, this is an awsome guide, thank you! I am in the beginning of the process. However, mistakenly I used flour/water 2/1. How can I continue with the feeding? Thanks for your help.
Hey that’s no worries, just continue from now on with a 1:1:1 ratio ☺️
great . thanks for the prompt reply.
Hi, second day and my starter has more than doubled. When I fed flour/water 1/1, water separated atat the bottom. What should I do?
Hi, I am still having problem with water separation on the third day and its only a bit bubble on the surface, the bottom is only flour. appreciate your tip.
Hey did you read through my FAQs in this post? There’s a question I’ve answered about water on the top of your starter”
Hi. I’ve set up my starter and it’s been fine and I’ve been making bread for the past 7 weeks, I feed me starter 1:2:2 and pop into fridge. This last week it’s not risen at all in the fridge and despite taking it out and referring it and leaving in in the hot water cupboard (stable in range temp) it hasn’t risen at all in 3 hours. Do you think it’s gotten contaminated? It still has bubbles through but it’s not rising. TIa
No I don’t think it’s contaminated. I would leave it on the bench for a couple of days and switch to feeding it 1:1:1 twice daily.
This is my first time making bread and I hope its not a disaster! I do have one question (I know not a good sign since its the first direction!) I don’t have a food scale…would this be 6 tablespoons flour to 6 tablespoons of water?? When I do the conversions it states 50grams of water is 3.38 tablespoons but this cant be correct as it is way too dry??
Hey use the conversion, that’s correct. You want equal weights flour and water and water is nearly twice the weight of the flour, so it makes sense it needs less tablespoons worth 😊. The consistency should be of a thick muffin batter when mixed
You are awesome thank you from Calif you should write a booklet. Your explanations are very helpful
Thank you very much! 😄
Hi! I just want to ask if i can start a starter using just Bread Flour? That’s the only one i have aside from APF but it’s bleached. Also, when you do a 2nd feed every 12 hours, do you also discard something or just feed? Thanks.
Heya you could use bleached flour if that’s all you’ve got but I think it may take a bit longer to establish itself since it probably won’t have as many wild yeasts present as on unbleached flour. And the second feed every 12 hours you do discard, it’s still 1:1:1. Only on day 1 and 2 is there no discard 😊
Thanks! That clears it up. As a follow up question, if i do not want to maintain a “discard jar” or if plan to bake bread maybe once of twice a week only, can i follow the “seed” method for my starter? I read it somewhere that you can take some “seed” starter from the “mother” starter (ex. 50 grams), put the “mother” back in the fridge and feed the “seed” to be your new starter so as not to have discards? If so, how long do i feed the “seed” before i can bake with it? Do i just do the 1:2:2 ratio and if it passes, i can go ahead and use it or do i have to strengthen my seed starter for a couple days?
Thanks so much for this awesome blog post Elien. Really easy to follow. Will be recommending your blog post to anyone wanting to start their own sourdough starter 🙂
Hello again Elien – I’m struggling a little with my starter. I have made 2 loaves over the past couple of weeks, but each time the starter hadn’t quite doubled when I made my bread (8 hours after I fed it 1:2:2). Because I had made my autolyse at the same time as I fed it, I felt I had to make the bread so I didn’t waste the autolyse. I notice in your comment to Bree yesterday, that you shouldn’t switch to 12-hourly feeding until it doubles within 5-6 hours of feeding. Is it OK then just to keep feeding it every 24 hours, even if has doubled after 8 or 9 hours? I have been feeding it when it has doubled and maybe that is where I’m going wrong.
Hey you are probably over feeding it a bit and it’s not having a chance to catch up. I would go back to 1:1:1 feeds 12 hourly until it’s ready ☺️. You can bake with that too, it doesn’t have to be 1:2:2. Just make sure to use it before it peaks and is too acidic.
I also wouldn’t worry about over doing the autolyse. I often start mine the night before. A long autolyse is great!
Thanks so much for that Elien – So just to be sure (because I’m super keen to make this a regular thing in my life): So long as it’s doubling within 5-6 hours of feeding I can continue to feed it 1:1:1 every 12 hours. So long as it’s doing that, I can use it to make my bread at any time to suit my schedule. I take it the peak is when it’s used all the food and starts to deflate (and becomes acidic and grumpy!) because it needs feeding again? Is there a sign when it is about to peak, or is that a matter of getting to know your starter?
yup that’s right. And if it would start rising and peaking too quickly, that’s when you could change the ratios to 1:2:2, to slow it down if need be, so it can fit within your schedule.
It is a matter of knowing your own starter to gauge that, but yes when it has peaked is when it starts to collapse on itself. It also can be quite runny at that stage. How quickly that happens depends on the temperature of your room as well as the ratio it is fed at.
Hey, my starter was doubling after 24 hour feeds so I switched to 12 hour feeds and now it’s hardly rising after 3 days (temperature monitored). Was it to early to start increased feeding?
Yup too early, just wait now for it to catch up (It will). Only switch to 12 hourly feeding when it doubles quickly within the first 5-6 of feeding.
Thanks! So to be clear should o go back to feeding once per day until it rises within 5-6 hours then switch to feeding twice per day?
Yup exactly that ☺️
I feed my sourdough starter and after a night, it starts separating with water on top(hungry), but it hasn’t increased at all. Does it still mean it’s hungry? Should I discard the liquid before feeding it? I’ve been mixing it in before feeding it. Bubbles are at a minimum too.
Hey I have some details already in the post about what to do if it splits. 😊 you can stir in the liquid or pour it off, it doesn’t matter too much.
Hi! thanks for this info! Question: can i use different flours to feed my starter? eg: say i start with rye for the first week till my starter is going strong, then I swap to bread flour/plain flour? (I’m thinking this would save costs as rye is more expensive than plain flour) and if all I’m doing is feeding it to keep it alive, then it really doesn’t matter what flour I use?
Hey yup you can absolutely do that 😊