Ripe Sourdough Starter: What does "ready to use" look like?

Sift’s Spring issue goes into sourdough baking in depth, with articles on sourdough breads and the sweet side of sourdough. To complement those recipes, we’d like to share this Techniques column. How do you know when your sourdough starter is ready to bake with? Let’s take a look.
We’ve answered hundreds of questions on this topic, but in this case it seems some pictures could well be worth a few thousand words.
sourdough Starter

Wake up your sourdough starter

Your starter has been tucked safely in the refrigerator for… awhile. Ten days, maybe longer. It’s separated, with a few tiny bubbles in the bottom, and a layer of grayish-looking alcohol on top. This is the sight that generates a lot of phone calls to our hotline. Can this possibly be OK? Is it dead?

Despite its current uninspiring appearance, this starter is still capable of doing great things.

sourdough Starter

Your sourdough starter’s first meal

Stir everything back together (some people just pour off the top layer, which is OK, too), discard half, and feed the remainder with equal weights of flour (a scant 1 cup, 4 ounces) and water (1/2 cup, 4 ounces). Mix well, cover, and leave on the counter for 12 hours. Repeat the discard and feeding process every 12 hours, leaving the starter on the counter. After a few feedings, you’ll see the starter becoming more and more active, doubling in size in a shorter time.

Looking for ideas of what to do with that discarded starter? Visit this page to get a whole collection of recipe ideas.

sweet sourdough baking via@kingarthurflour

Get ready to bake

This is the same starter after a few days of the regular feedings described above. We stirred, discarded, and fed it with flour and water at 8 a.m. (2 hours ago). Now we’re going to watch its development. See the number and size of the bubbles increasing?sourdough starter via@kingarthurflour

Active, but not ripe, sourdough starter

The same starter at 1 p.m., 5 hours after feeding. It’s beginning to expand, and has many more bubbles. If you watch it for a minute, you can see the bubbles forming and coming to the surface in slow motion. This is an active starter, growing and expanding, producing bubbles of carbon dioxide. But it’s not yet ripe (at the top of its yeast and bacteria growth arc), nor at full strength for raising dough.sourdough starter via@kingarthurflour

Ripe and ready to go

The same starter at 4 p.m., 8 hours after feeding. It’s doubled in volume, and shows signs of just beginning to sag under its own weight. This is active starter that’s also ripe, ready to be added to bread dough to perform its sourdough magic. After mixing it into dough, then some rising and folding, the dough can be shaped and refrigerated overnight to be baked tomorrow.

sourdough Starter

The best way to measure sourdough starter

An important thing to note about measuring sourdough starter: The more bubbles in it, the less a cup of active, ripe starter weighs. Measuring by volume can mean you have more or less starter in your cup, depending on where it is on its growth curve. That’s not a deal breaker for your recipe, but having a different amount of starter than called for may change the rising times and finished size of your loaf. To be sure you have the lifting power you need, measuring ripe starter by weight is always a better choice.

Once you gain confidence that your starter is vigorous, you can move its “get ready” feeding to the evening, knowing your starter will be ripe next morning to mix into your dough.

Your sourdough baking adventures await. We have lots of ideas (more than 150 recipes) to help you navigate this tasty and rewarding style of baking. Be sure to visit our sourdough guide for more in-depth information about creating, maintaining, and baking with sourdough.

At Sift, we live and breathe baking, and hope you’ll join us. Baking together is always more fun.

Susan Reid

Chef Susan Reid grew up in New Jersey, graduated from Bates College and the Culinary Institute of America, and is presently the Food Editor of Sift magazine. She does demos, appearances, and answers food (and baking) questions from all quarters.


  1. Donna Wigmore

    Can I double the amount of starter to double my batch. My recipe only makes one loaf and that seems silly.

    1. The Baker's Hotline

      If you’re looking to increase the volume of starter you have, Donna, you can simply add more flour and water to your starter at each feeding, building it up slowly until you have the volume you’re looking for. For instance, you can take 1 cup (227 grams) of starter and add in 1 cup (227 grams) of water and 2 scant cups (227 grams) of flour. This will give you about 2 cups of sourdough starter. You can also increase the amount of flour and water that you mix in, say to 300 grams each. Keep in mind you want to use equal parts flour and water by weight, and you want to use “reasonable” ratio of starter to flour and water. (Try using between one to two times the amount of flour/water to starter for best results.) We hope this helps, and for more tips, check out our full Sourdough Baking Guide. Good luck! Kye@KAF

  2. Kathleen Ruba

    I just made my first starter two days ago. It’s already tripled in volume. Is that okay? Also, when I feed it, do I have to discard half before I add any new flour and water? Thank you!

    1. The Baker's Hotline

      Hi Kathleen! The fact that it’s growing is great, keep in mind it usually slows down around day 4 but it will pick back up. And before feeding with flour and water, you’ll want to discard all but 1/2 cup (113g) and then you feed that with an equal amount of flour and water, so 113g water and 113g flour. You can use smaller or larger amounts of each, you just want to make sure the ratio of starter:water:flour is equal by weight. Happy baking! Annabelle@KAF

    1. The Baker's Hotline

      Hi Jan. The difference between the two is that it’s simply a different fermented ingredient that’s producing the carbon dioxide. (Bubbles!) Our starter is fueled by fermenting flour, potato starters are fueled by fermenting potato flakes. We’ve pretty much only worked with flour starters so that’s our specialty, but there are definitely resources out there if you’re looking to make a potato-based starter. Annabelle@KAF

  3. Natalie Ransford

    I was blessed with 110+ yr old starter…my cinnamon rolls are better than Cinnabon, as proclaimed by the many folks who have tried them. I have read a multitude of sourdough starter recipes. When i was given the starter i was also given the instructions to feed it. Recipes for bread, dinner rolls and cinnamon rolls…
    This recipe makes a slightly sweet fluffy soft white bread…
    I feed my starter with 3/4 C sugar, 3 Tbs instant potatoes, 1 C AP flour, 1 C room temp to slightly warm water, and the whole jar of my 3-7day old starter from the fridge, all mixed together in a large glass bowl. I let it sit at room temp for 8-12hrs. Remove 1 1/3 C of starter for my recipe, return the rest to a1/2gallon jar, cover with hole punched lid and back to the fridge with my starter. My 1 1/3 cup starter produces 3 loaves, or pan of cinnamon rolls, or trays of dinner rolls. I can make 3 of whatever.
    My dough recipe is 3/4 C sugar, 1/2C oil, 1C bread flour, 1C warm water, 1 1/3C starter. Combine, roll ball with oil to coat, lightly cover with parchment and let rise for 8-12hrs. Punch down, divide into 3 portions. Form in to 3 loaves, 3 pans of rolls or make cinnamon rolls.
    Let rise ar room temp til doubled…8-12hrs..if this process has not happened, my neice will get a severe tummy ache, as she has a gluten intolerance. So if put into the fridge after forming into whatever, and it rises there it will not degrade the gluten…time at room temp seems to be the key…then to a 350° oven for 22min…exactly…set you timer!
    I cannot for the life of me throw any out 🙃. To shorten this novel, i now have 5 half gal jars of starter, having to start work tomorrow. I will not have the time needed to creat all the bread i must make…15 pans of various treats…i went in search of a answer to the question…why do some recipes call for HUNGRY starter…i only have experience with the fed starter…so…for now i will feed the beast…and divde and fill maybe 3 more jars…and pribably need to quit my job and start making cinnamon rolls to sell😁😁😁

    1. The Baker's Hotline

      If you feel like driving any of those legendary cinnamon buns to Vermont, Natalie, they would be greeted by a hungry KAF reception! We’re so interested to read the note about the sourdough products you bake and your niece. Because wheat is a gluten-containing ingredient, we wouldn’t recommend anyone who has to avoid gluten eat a wheat-based sourdough without checking with their doctor first; however, we’re genuinely glad that you’ve found this has worked well in her case! Keep up the great bakes! Annabelle@KAF

    2. Donna Wigmore

      But Natalie, there are recipes that use the discard. Lots and lots of them. I am just getting started, but there are plenty of options on the King Arthur site. I have also come across someone in my reading who never throws starter out, but I haven’t gotten my head around their plan yet.

  4. WILLIAM B Moles Jr

    I made some starter, but after 4 days it separated and had a thin texture. There is a good fermented smell. I stored it and covered it back up. It’s on the kitchen counter. I don’t know if it’s still alive or notmal.

    1. The Baker's Hotline

      Totally normal, William! Keep going. It’s usually weird for the first 7 to 10 days then it becomes more regular and consistent. Annabelle@KAF

  5. Judy

    I have made your recipe for sourdough starter in the past but wasn’t making enough bread so I gave up and threw the starter out. The breads were good but didn’t have the tang that San Francisco sourdough has. I grew up in the San Francisco Bay Area and I had a bakery near me. So recently we went on a trip to San Francisco, specifically, Pier 39 and there was a bakery/restaurant there with bakers making crab shaped french bread in the front window. They had sourdough starter packets for sale. I’m attempting to make a starter but it doesn’t rise. It looks like a thin pancake batter and doesn’t have any bubbles.Tomorrow I plan on putting together your recipe in another jar. Maybe I’ll have better luck. Do you think because I no longer live near San Francisco, I cannot make french bread to taste like theirs?

    1. The Baker's Hotline

      Having grown up in San Fransico as well, Judy, and making many a trip to Pier 39, I can fully understand the desire to replicate the bread of the city. A section of our Sourdough Guide FAQ’s reads: “Why doesn’t your bread taste like San Francisco (or New York, or Key West) sourdough? Because there are so many variations—in starters, weather, the microclimate in which you’re baking, and the recipe you’re using—that it’s nearly impossible to duplicate exactly someone else’s sourdough bread. Your best bet is to follow a recipe, and discover what you can do with YOUR starter, in YOUR kitchen.”
      We encourage you to experiment with lots of sourdough bread recipes until you find that one that most closely resembles the flavors you love. My favorite is our Naturally Leavened Sourdough Bread using rye flour in place of the whole wheat, but you’ll never know which one is the best fit until you do some very tasty testing. Happy baking, and always feel free to call our Baker’s Hotline at 855-371-BAKE (2253) for extra tips and tricks. Annabelle@KAF

  6. Katherine

    I neglected my starter for a few days and when I checked on it, it looked like your photo with the liquid on top. But then I discovered a substance floating on the surface of the liquid that seemed EXACTLY like a kombucha SCOBY. I do brew kombucha, so I was wondering if that’s what it is? The starter even had the same kind of vinegar smell as my kombucha. Any thoughts? I actually put the alleged SCOBY in some tea just to see what happens.

    1. The Baker's Hotline

      Hi Katherine, we haven’t heard of something like this happening before with a sourdough starter, and it makes us a bit weary to hear about unidentified things growing in your starter. We’d recommend airing on the side of caution since you’re not sure what kind of yeast/bacteria culture has formed and simply start fresh (discard the affected starter). Food safety and the well-being of our customers is of utmost importance to us, so we’d recommend being prudent in this case. Kye@KAF

  7. Cindy Vice

    Which is better sourdough starter made with yeast or just plain flour & water?
    What is the best way to store – in a mason jar with lid just barely on, covered loosely with plastic or just screw the lid on regular?
    What is the ideal temp for growing a starter – my house is usually between 68 & 74 degrees?

    1. The Baker's Hotline

      Hi Cindy, when it comes to sourdough baking, there are no hard and fast rules about what is “better.” If you ask what makes the best sourdough starter to a room full of bakers, you’re bound to get dozens of answers. We prefer using this recipe to make your own sourdough starter, which uses a basic combination of whole wheat (or whole rye) flour and water to capture the wild yeast from the environment. (Sometimes adding a bit of commercial yeast to “kick start” your starter can be helpful, but it’s usually not necessary.)

      For storage, we like keeping the sourdough starter in a crock with a loose-fitting lid like this, but a mason jar with the lid slightly ajar works well. Avoid screwing the lid on tightly to allow some gas exchange. It sounds like your kitchen will make a cozy sourdough home. Ideal temperature for sourdough is between 68°F and 70°F. (Check out this post about growing your own starter for more details.) Kye@KAF

  8. Drew

    My starter seems to rise and fall in a span of about 4 or 5 hours. I’ve been using it at its peak somroughly half that time. I get decent results. Should I try using it at 8 hours? Everything thing I read says you should use your starter at its peak.

    1. The Baker's Hotline

      Glad you hear you have a very active starter, Drew. Using it at it’s peak is ideal for getting the best rise out of your bread, though there isn’t necessarily a wrong time to use it. We encourage you to experiment using it at different rising and/or falling points to see which stater-state results in your ideal loaf. It would be a tasty experiment indeed. Annabelle@KAF

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