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. Katy

    How to get my sourdough to taste more “sour”? Thanks to King Arthur & with additional support from the wonderful HELP! line, I have a fantastic starter which gets regular use .. about once a week. And thanks for all the delicious “discard” recipes. That said, my son & husband comment that while the bread IS delicious, it does not taste “sour”. Suggestions?

  2. cynthia

    hello…started my starter on a friday, out of town til Monday, starter a little bubbly, fed with 25gn rye 25gm of bottled water…been feeding every 24 Tuesday, very bubbly and can see the glutens forming, doubled in size, did the float test and sank like a torpedo….been feeding with the same 25gm rye with 25gm bottled water, without the discard…..its very bubbly, with those gluten strands, is it ready? my first time doing this


    1. The Baker's Hotline

      Hi there, Cynthia! We always recommend that you discard as is it very important to keep the starter balanced and make room for new yeast cells and good bacterias to grow. You can see our recommended feeding process in our blog article, Maintaining your sourdough starter. We’ve found that the float test isn’t always a conclusive tell of whether the starter is ready to be used, you can read more about this in our post, The float test for yeast dough and sourdough starter. You can certainly use the float test if you’d like, but we’d recommend using it in addition to the visual tips outlined here in this blog article. We hope this helps to clarify! Morgan@KAF

  3. Tammy

    I have tried several times to create my own starter, I have tried starting with unbleached flour and I have tried starting with wheat flour, I get lots of bubbles but never any growth. I have tried keeping it in the oven and just on the counter top. The only thing I can think of is maybe my water, does that have an effect on it?

    1. The Baker's Hotline

      Hi Tammy! We’re sorry to hear that you’ve had some trouble creating your own starter. We’ve tested creating starters with all kinds of water and found that if it’s safe for you and doesn’t smell of chlorine, the starter should be just fine. You’re more than welcome to try it with bottled water though. We’d recommend just sticking with the feeding the starter every 12 hours until you see it bubble and almost double in size — every starter is a bit different and some times it can take a bit longer for them to become mature and predictable in its activity. We hope this helps and happy baking! Morgan@KAF

  4. Lynn Robertson

    Before measuring out my starter to make bread, should I stir it down first or just pour it out?

    1. The Baker's Hotline

      Hi Lynn! If you’ll be measuring your starter by volume you’ll want to stir it down before measuring, but if you’re weighing your starter you can just go right ahead and pour it out. Happy baking! Morgan@KAF


    I followed the recipe from KA Baker’s companion, (rye, water, tiny bit of molasses). I’m a week in and still have that nail polish smell. Feeding twice a day with KA unbleached flour. When will it smell bread like?

    1. The Baker's Hotline

      Hi there, Laura! We might suggest feeding the starter just once a day for the next few days to see if that helps to mellow out the aroma. It sounds like the starter just needs a bit of time to balance itself out. If we can chat further with you about your starter, please feel free to give our friendly Baker’s Hotline folks a call at 855-371-BAKE (2253). Kindly, Morgan@KAF

  6. Cindy Farmer

    My starter has been slow to develop. I am placing it in the oven with the light on and that seems to help. However, my starter has a thick film across the top. Should I remove this before stirring and feeding or stir it into the starter? I have not seen this mentioned anywhere. Thanks!

    1. The Baker's Hotline

      Hi Cindy! If there’s a skin, that should be removed, but it shouldn’t develop a skin if you can help it. It sounds like the light is drying it out so keeping it covered with plastic wrap (even putting the plastic wrap directly onto the starter itself) should help prevent any skin from forming. Annabelle@KAF

    2. Cindy

      Thanks. The starter actually was growing much st to hat point but once it did there was no skin.

  7. Derek

    I have a starter that I’ve been feeding daily following a recipe in one of my bread books. It rose well the first couple feedings, but slowly seemed to get more and more liquid in consistency. It’s been a couple weeks now and it smells great but doesn’t seem to rise. Lots of bubbles form and pop at the surface, but the volume of the starter doesn’t really seem to change. I’ve been feeding it by weight 60g water/60g KA bread flour, pouring out half before feeding. Any thoughts? Do I need to feed it more often? I.e. twice daily as your blog suggests?

    1. The Baker's Hotline

      Hi there, Derek! We’re sorry to hear that you’re having some trouble with your sourdough starter. If you’re leaving your starter out at room temperature, we do suggest feeding it every twelve hours. The warmer temperatures will cause the starter to ferment and as that process goes on the starter will become thinner in consistency and sluggish in its activity. Our Baker’s Hotline folks are also always happy to help troubleshoot starters, you can reach them at 855-371-BAKE(2253). Kindly, Morgan@KAF

  8. Teresa

    My starter is flourishing, but it doesn’t have the aroma of sourdough. I started my starter with unbleached flour, then changed to wheat. It is about 3 days old, with the wheat flour, but over all it is over a week old. Is there anything else I can do?

    1. The Baker's Hotline

      Hi there, Teresa! We’d suggest just giving your starter a bit more time. It can take a couple weeks for a sourdough starter to become established and have the aromatic smell that is often attributed to starters. While feeding the starter whole wheat flour will give it a more pronounced aroma, the starter is still in the early stages of being created. We hope this helps and happy baking! Morgan@KAF

  9. Betty DeSantis

    After using KA recipe for a week and a half on sour dough starter I just gave up. It only rose the first few day or two and the following days stayed the same, I did not use unbleached flour could that have been the cause? Or I did not weigh it out, only used measuring cups to extract, save the starter and adding water and flour. Should I have had more patience with it?

    1. The Baker's Hotline

      Hi there, Betty! We’re sorry to hear that you had some trouble when you were working on creating your own sourdough starter. It sounds like there were a couple of things happening that would cause the starter not to rise. Using a bleached flour to feed your starter can kill off the yeast cells that you’re working to cultivate and grow. Also, measuring in volume can result in a starter that is too thick and doesn’t rise well. While we do find that weighing flour yields the best results if you prefer to use volume we suggest using the fluff and sprinkle technique to measure the flour. We hope this helps should you decide to give making your own sourdough starter another go! Morgan@KAF

  10. Alison

    I just got some starter and have been feeding it as directed. A couple of questions…(1) t appears to be quite vigorous, but based on the comments in this article and elsewhere in recipe comments, should I be measuring the height of the starter in my container to see where it is in the cycle? (2) I also see various comments on the relative weight of fully ripe starter and underfed or older starter–what should a cup of ripe starter weigh? is this dependent on how much water and flour is in it, as well as on ripeness? (3) my starter is very “chewy”–it is hard to pull apart and work in new flour and water, although it can be done. Do I need to use more water or something? I live in Denver, which is a dry climate, and often use a little more liquid. I have done that to a minor degree already with the starter, but am afraid to screw it up if I depart from the instructions too much. I am an experienced baker, but not with sourdough.
    thanks for the help!

    1. The Baker's Hotline

      Alison, these are great questions! It does sound like your starter is a little low on hydration. It should look and feel a bit like pancake batter in consistency. Feel free to add a bit more water to your feedings until it seems about right. We usually add equal amounts of flour and water by weight, but if your starter seems to dry out quickly due to your climate, you might need to adjust it. As far as measuring the volume of your starter goes, the easiest way is to keep it in a clear container and put a mark at the top of the unfed starter. (Dry erase marker or a rubber band wrapped around the container both work well.) This way, it’s very easy to see when it has doubled in size. The weight of fed starter by volume will vary wildly, which is why it’s best to use weights when adding fed starter to a bread dough. We hope that helps! Kat@KAF

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