Converting Yeast-Based Recipes To Use A Sourdough Starter

Once you have a natural starter alive and kicking on your counter, stealing the occasional banana from the fruit bowl, it’s hard to go back to baking bread with commercial yeast.

Not only would that feel like a bit of a betrayal (though you can always blindfold the jar of starter or work under the cover of night) but every loaf is an opportunity to strengthen your starter as well as your skills. And frankly, you’ve gotten used to the vivid flavor and lasting freshness of sourdough-powered bread, so you’re a bit spoiled.

Most breads leavened with commercial yeast can be leavened with a natural starter. It is just a matter of converting the recipe; all you need is a calculator and a play-it-by-ear disposition.

That’s not to say you want to limit yourself to those recipes written with a starter in mind: even though baking with a natural starter has the ancestral high ground and is regaining considerable popularity of late, it is still practiced by a minority of home bakers, and most of the bread recipes out there call for commercial yeast.

But of course, most breads (see caveats below) leavened with commercial yeast can be leavened with a natural starter. It is just a matter of converting the recipe; all you need is a calculator and a play-it-by-ear disposition.

So, how do you go about it? There is no single method* but I have had good success with mine, so I wanted to share it with you below. If you want to chime in with your own method and experience, I’ll be most interested to hear them.

My approach is based on my love affair with Flo’s 1.2.3 formula, in which the bread dough is made by combining 1 measure of 100% starter (= a starter that’s fed an equal weight of flour and water at every meal), 2 measures of water, and 3 measures of flour — all measures understood in weight. This means that the bread dough ends up being made of 16 starter (and 26 water and 36 flour).

Example: I make my standard loaf with 200 grams 100% starter, 400 grams water, and 600 grams flour. Once all these ingredients are combined, my bread dough weighs 1,200 grams, or 1.2 kilos (I’m neglecting the weight of the salt), 16 of which is the weight of the starter [1,200 ÷ 6 = 200].

A natural starter works its magic at a much slower pace than commercial yeast, so I’ll allow for a longer resting time than stated in the yeast-based recipe.

When I want to convert a recipe that uses commercial yeast, I aim for that same starter ratio: I add up the total weight of water (and any other liquids) and flour (or flours) in the dough, and estimate that I’ll need 16 of that weight in 100% starter to leaven that amount of dough. (Any ingredient that is neither liquid nor flour, such as nuts or seeds or fat or sugar, is neglected here.)

Example: Let’s say I want to convert a yeast bread recipe that calls for 415 grams water and 605 grams mixed flours. The total water + flour weight is 1,020 grams [= 415 + 605], and I estimate I’ll need to use 16 of this weight in starter, which amounts to 170 grams [= 1020 ÷ 6]. (I round the amount up where necessary.)

Naturally, because starter is made of flour and water (with a friendly colony of yeasts and bacteria), I can’t just add it to the rest of the ingredients and proceed without changing anything else; it would throw off the balance of ingredients, and therefore the texture. Instead, I need to account for the fact that my 100% starter is half flour half water by lowering the amount of water and flour accordingly.

Example: In the yeast bread recipe described above, I’m planning to use 170 grams of 100% starter, which is equivalent to half water and half flour, that is to say [170 ÷ 2 =] 85 grams of water and 85 grams flour. So I’m going to lower the amount of water and flour by 85 grams each. I will therefore make my dough by combining 170 grams starter, 330 grams water [= 415 – 85], and 520 grams flour [= 605 – 85], which all adds up to 1,020 grams bread dough [= 170 + 330 + 520], as originally intended.

Starter conversion

Then, when the bread dough is mixed and kneaded, I’ll follow the rest of the recipe with a few necessary changes: a natural starter works its magic at a much slower pace than commercial yeast — thereby fostering the development of desirable flavor components — so I’ll allow for a longer resting time than stated in the yeast-based recipe. Sourdough-leavened doughs also ferment during a single rise (with absolutely no punching down), so the method may have to be modified in that regard as well. Key here is the use of one’s experience and observation skills to determine what the dough needs for this particular recipe.

Such conversions work best for “real” bread recipes, those that are chiefly based on flour, water, and yeast.

I will note that such conversions work best for “real” bread recipes, those that are chiefly based on flour, water, and yeast. If a dough is enriched by the addition of sugar, fat, or eggs, these elements tend to slow down or even inhibit the action of the starter, and the dough may take a very long time to rise, and might not reach its full potential. In such cases, I will use some of my starter as described below, but keep a portion (say half or a quarter) of the commercial yeast that the original recipe calls for.

All this is to say that, before you start converting and toying around with recipes, I recommend you take the time to get perfectly comfortable with your starter, the way it behaves, the feel of the dough, and the techniques involved. Once you’ve honed your skills on basic starter bread recipes, you’ll have developed enough of a baker’s intuition to successfully convert recipes.

* You can also take a look at the methods offered here, here, and here.

  • The Paris Food Blague

    yes…it is so good to hear someone say that “real bread” only has flour water and yeast….after a visit to the united states i could only find bread full of sugar and preservatives.

    also your post reminded me why my bad baking skills might be in direct correlation to my terrible high school science skills.

  • I love math and can handle fractions with aplomb … as long as you stay away from sixths! Not sure why but they give me conniptions.

    But I’m always a sucker for any recipe that requires both a calculator and a sense of play-it-by-ear.

    Cheers and thanks.

  • Just looking at this post and seeing MATH made me cringe (and this is why the US is losing its international edge), but you’ve done a great job making this a really approachable process. Thank you!

  • gingerpale

    I use starter for the “no-knead” bread. Just a sloppy tablepoonful or two into a cup, with water added to equal the original amount of water in the recipe. No math!– but now I’m thinking some measuring could make the rising time and moisture content more predictable.
    I’m glad you mentioned that “flavored” breads don’t benefit from starter–I’ve thought about it but now won’t bother.
    Also, I’d like to say that my 7 year-old starter is *just now* starting to get sour enough for me! I live in dry Utah, not so many airborne beasties as in other places, I guess.

  • I usually substitute 30g of starter for each 1/2 tsp of yeast. I made doughnuts using this substitution a couple of weekends ago, and they came out great!

  • J’en rêvais, Clotilde l’a fait !

  • “Blindfold or work under the cover of night.” Beautiful, I wish I’d though of that first.

  • Clotilde, nice post!
    Another way to approach the subject is by introducing the concept of ‘pre-fermented flour’. If, for example, one has a recipe which uses a pâte fermentée or poolish and wishes to convert it to a sourdough recipe, one would calculate the amount of pre-fermented flour in the pâte fermentée or poolish, based upon its hydration, and then calculate the amount of sourdough starter that would need to be used in order to maintain that same amount of pre-fermented flour. Of course, the amount of added water in the recipe would have to be adjusted.
    As an aside, I feel compelled to address the comment that ‘real’ bread only has flour, water and yeast (no salt?). Is it possible that the comment was actually meant to refer to ‘lean’ breads rather than to ‘real’ breads? Bakers of breads such as brioche or panettone would, I’m sure, insist that they are baking ‘real’ bread! :)

  • Wow, i’m inspired to start making bread with a starter now! Would the same starter ratio apply when using a wholewheat flour?

  • I don’t use math either, but have been baking a rough variation on Ed Brown’s Tassajara yeast bread as a plain rye sourdough, with fine results.

    By eliminating the “extras” (dry milk, oil, sugar, etc.) and replacing the yeast with sourdough starter (however much I have on hand…usually a couple of cups), but keeping the basic water, flour and salt proportions, I was able to come up with a very workable but loose recipe.
    Rising time is not specific, but then, unless you take the temperature of your water and flour, it never is anyway.

    My rule is, replace yeast with whatever starter you’ve got around (don’t get excessive, probably keep at least 50% new flour), make minor adjustments to water/flour amounts for proper hydration, and wait as long as your bread takes to ferment. If it does take a long time to ferment, a couple of “punching-downs” will even the temperature and strengthen the dough so it doesn’t get sloppy.

    Sourdough is the best!

  • Sam

    Making mathmatics interesting!

  • Thanks for the bread starter conversion equations.

    Perhaps the commenter looked in the wrong places(chain supermarkets?) when in the US. I have no problem, even on this rock, getting beautiful bread, when not baking my own. Generalizations can get tiresome. I

  • Anne

    how strange, I was just wondering myself how to convert yeast recipes but with your advice and that of Flo on votrepain, I concluded that I should stick to basic starter recipes and get to know my starter better first: next trial this coming week-end : your crumpets….
    autre question un peu étrange : est-ce votre mère qui tient un blog de couture ? (j’ai trop de projets : pain, feutrage, papier recyclé,broderie et consulte parfois le site coupecouture…)

  • This is great timing, as I’ve just taken the plunge into sourdough this past week, and have begun to get a little obsessive about it. I too was sitting at the table a couple of days ago with a calculator trying to work out hydration for a recipe that called for a firmer starter than Giselle, who’s at 100% (someone really should compile a list of sourdough names – are people more likely to choose a name from the opposite sex, for example?). I’m looking forward to trying your levain recipe this week.

    I also have to commend the clarity of your original natural starter bread post. I’ve been reading a lot online and there’s a great deal of confusing information out there for new wild yeast herders. Either people oversimplify the process or frighten people off with too much information. Thanks!

  • You know, I can’t tell you how many times I’ve googled how to convert dry yeast to my starter. Can’t wait to play with this!

  • wow, that is pretty hardcore that you have all of these equations to get this recipe perfect! never thought about using something else other than yeast to bake bread, but thank you for sharing your knowledge!

  • I love bread made with a starter. It is so good. I have not used the starter with flour. I have just used one with potatoes. It is so good.

  • Thank you for the link, and that easy-to-remember formula.

  • Thanks for your comments — so glad you find this useful! — and for sharing some of your own conversion methods.

    Joe – I normally make bread with a mix of white and partially whole wheat flours, and have had good success with these.

    SteveB – Great point about the pre-ferment/poolish. Those are recipes that lend themselves particularly well to the conversion.

    About my comment on “real” bread, I didn’t mean it in a disparaging way for the rest of the yeast-raised world. But from a semantic point of view, I do think the term “bread” designates first and foremost a mix of flour and water, with or without a leavening agent, with or without salt (as per the dictionary definition). And to me at least, there is a divide between those “real” breads and other things we might call breads for lack of a more appropriate word, but build upon and therefore depart from that original concept.

    I do love brioche, and I agree it is a part of the bread baker’s repertoire, but brioche is not what I think of when I think of the essence of bread.

    Andrew – I really like your idea of compiling starter names, and I think you’re on to something when you say that, whatever our gender, we tend to assign the opposite one to our starter.

    This might not be quite as true of French bakers, though, because the French word for starter is a masculine noun (le levain) so we probably all think of it as a masculine entity.

    And thanks for the kind words about my starter bread post — much appreciated!

  • Good afternoon,
    Interesting post.
    I am a great fun of sourdough starters and fermented flour.
    I do not appreciate commercial breads and, to be frankly, sometimes “suffer” in France, as in general, a great number of breads I test contains commercial starters and softeners.
    I am Polish, “bread” tradition is very strong there.
    I know at least few very interesting Polish blogs (unfortunately, in Polish) concerning breads, bread baking, and various sourdough starters.
    Very often, sour rye starter is used.
    Fermented sour flour (rye or wheat) is used not only for breads, but for preparation of soups: for example, extremely popular sour rye soup in Poland – “zurek” or “white bortsch”. I hope you will try it once – it is great!
    Kind regards.

  • Heidy

    Thanks so much for posting. (I have two starters, one whole wheat flour sourdough, one with potato water and sugar. They feel like pets that must be taken care of and I feel badly when I forget to feed them. But they always bounce back!) I really appreciate your calculations and look forward to converting my grandmother’s bread recipe. Thank you again!

  • EB

    Uh oh.. baking AND math?? I’m not so sure…

  • Clotilde, you (and Flo) made me start my new journey with sourdough starter. I never thought I would do it and enjoy it as much!! Merci!! Sure, I am still in the infancy stage but always looking for something new to make: savory cakes, pancakes, pizza doughs, etc. I will definitively keep this great post handy as I make more bread.

  • I love math, and even though I won’t be mixing up a sourdough starter any time soon, I love this post. :) For now, I am giddy about baking bread several times a week from a very large batch of no-knead bread dough resting in my fridge. There is nothing like the smell of home-baked bread in the oven. Joy!

  • Very nice post. Someday when I’m not working 14 hour days, I’ll try it myself. After all, I live in France and I should learn how to make homemade bread!

  • Deb

    Perfect timing. I just received the starter for my starter (from King Arthur Flour). Can’t wait to make some pizza dough!

  • yay, keep those starter recipes coming! mine is called “tamagotchi” and those sourdough baguettes were a success! been baking bread since i was 15 and i hardly seen a bread that contained a ryeflour (from the starter) rise as much as these baguettes…

  • Magdalena – I did not know there were soup recipes that called for starter, how interesting. Do you have a recipe for zurek you could share?

    Heidy – Let me know how the conversion works out!

    Gaelle – Such an exciting adventure, isn’t it?

    Anna – I’m delighted you had good success with the baguettes, thanks for reporting back.

  • Hello Clotilde,

    of course, I have a recipe for “zurek”, this is one of my favorite Polish soups, and more importantly, I have the recipe for home made sour rye base, which is the key for the soup. I always make the starter on my own.
    I will share with pleasure!
    I will put the recipe on my blog in following days, as soon as I will finish translation, and then I will come back to your post.
    Have a nice afternoon.

  • Judy

    Clothilde, I really hope your next book will be on sourdough! I’ve converted a few recipes just by estimating the amount of water and flour in the starter and subtracting those amounts from the recipe. Your method is much more precise.

  • Your post is beautiful and makes me feel like I am not crazy not liking most of the commercial bread. Making it myself is scary at this point, but I will save your post for when I gather the courage to face my Baking Anxiety Disorder.

  • Hi Clotilde, I’ve been a reader for a while now and greatly enjoy your blog. I’m in my second week of cultivating my new pet sourdough starter and can’t wait to get baking. Thanks for posting so much about your sourdough exploits, hopefully I’ll have more to add to the debate soon! And yes, I called mine Steve, so Andrew may be on to something. Thanks again gemma :)

  • juliadevi

    another soup using starter: the perennial moroccan favourite harira.
    i’ve never made it myself but here is a recipe recommended by my cooking teacher in morocco (in french)

  • Good afternoon Clotilde,

    as I promised last week in my comment to your post on sourdough starters, here is a link to my sour rye starter recipe and Polish “żurek” soup made with the starter.

    I allow to put a link, as the recipe and remarks concerning both the starter and the soup are long.

    Regards and have a nice day!

  • Judy – Thanks for the kind suggestion; I have a lot to learn before then, but it’s certainly a project to think about!

    FrenchPressMemos – If it’s any encouragement, I used to be paralyzed at the thought of using yeast, so it’s really a disorder one recovers from. :)

    Gemma – I hope you and Andrew have a long and productive relationship. :)

    Juliadevi – Thanks for the tip! It seems harira would be a great way to use extra sourdough starter.

    Magdalena – Thank you very much for this link, I’m really pleased to learn more about this Polish staple.

  • Hilary

    Thank you thank you thank you!! I’m usually just a lurker here, but had to comment to say, “thanks!!”

    I make different breads almost weekly, but can only consume 1 small loaf a week. I’ve been working with my sourdough starter for almost 2 years now and love it, but have a hard time using enough of it. When I make sourdough baguettes or boules I generally freeze a loaf or two and then I don’t need to use it again for another two weeks (unless I decide to make a commercial yeast bread).

    I hate to throw away starter when feeding it am thankful for a way to begin using my starter nearly everytime that I make bread. Sometimes I also make pancakes or english muffins to use up extra starter, but knowing how to use it alone in more breads will be a wonderful skill to have.

    Thank you!

  • est

    Clotilde, this is amazing and so helpful!! thanks for taking the time to post this precious information…
    converting recipes doesn’t seem daunting anymore!
    I still wish we could make sourdough brioche though… but maybe i’ll start with making some with commercial yeast.
    thanks to you, I’m now officially hooked on sourdough !

  • Hilary – I also make a couple of loaves at a time, keep one for eating during the week, and freeze the other one, or give it away — freshly baked bread makes a great host(ess) gift!

    Est – So glad you’re getting along with your starter! Have you given it a name yet?

  • Agnes

    I am not a bread baker, but I love your post! This recipe conversion is very interesting to me, since I taught the course ‘mass and energy balance’ in an university for chemical engineering students. The principle is easy (what comes in should go out), but it can be tricky when you have many streams. When I was teaching, I also made similar figures as the one you made here.

    But chemistry has a lot of similarity with cooking – the difference is that you got a tasty, good-looking, product after cooking!

  • d e bartley

    I had a sourdough starter for 3 years, just kept adding to it and baked my bread 2 times a week. It worked when I lived in California, living on the east coast, the starter takes alot longer to get going. Sourdough works better on the west coast, why is that??

  • Thanks for reminding me to stop neglecting my starter! I just fed him (he’s not named …. must start brainstorming!). I don’t eat too much bread, but now I know how to translate doughs to sourdough the starter won’t be as neglected. I think I will first try sourdough-ing “hot cross buns” for Good Friday/Easter. Thanks for the great advice!

  • Sophie

    Bonjour Clotilde, merci pour cet intéressant billet. Je suis une adepte de la méthode 1.2.3 qui marche en effet pour toute sorte de pain et j’ai commencé à essayer mon levain dans les cakes/muffins/quatre-quart… Je trouve que ça ne marche pas mal du tout et que les gâteaux se conservent bien. Mais j’y vais un peu à l’instinct sans vraiment avoir de méthode calculer combien de levain mettre dans une recette qui “appelle” de la levure traditionnelle. Quand vos pérégrinations culinaires vous conduiront jusqu’à l’étape levain et pâtisserie, je suis preneuse de votre formule magique!
    En attendant, longue vie à votre blog (et à votre levain!),
    Bien amicalemement,

  • Hey Clotilde, thanks for sharing this and your whole journey with levain and baking with it. I’m having a wonderful time and if you hadn’t done this research and presented it here, I most probably would have missed out on this great experience.

  • Sophie – Il m’arrive de mettre du levain dans mes cakes, gâteaux, et autres, mais je mets quand même de la levure chimique parce que le levain n’agit pas du tout de la même façon : il faudrait lui laisser le temps de fermenter, etc. Pour moi, c’est plutôt une façon de ne pas jeter l’excédent de levain.

    Lucy – I read about your starter on your Kitchen Notebook, and was really pleased to know you’re dabbling in sourdough baking, too! I love the idea that it waits for you in the cool of the house from weekend to weekend. :)

  • Elliot hertz

    This article is as useful now as it was 4 years ago. Well done and thank you for it now it seems so simple. Yeast be gone.

  • danilo

    Hi Clotilde, Great post! i’m new at sourdough and I’m facing the following problem: I converted my “ciabatta” recipe (500gr flour + 375 water + ts sugar +tbs oliveoil) as you explained, but it doesn’t rise as much as with yeast, it comes way less soft (after about 12hours raising). What do I do? add a pinch of yeast? wait more? thanks!

    • It sounds like maybe your starter isn’t “strong” enough, or you’re not using it at its peak. If you’re new at sourdough, I’d recommend practicing with sourdough recipes (see mine here) to get familiar with the way sourdough works, before you try converting yeast-based recipes. Does that make sense?

      • danilo

        Thanks! i’m reading all you recipes to make myself a better idea of how to properly use a sourdough starter. Starting now with a sponge and bake tomorrow and see if it gets any better. Thanks again, it’s very nice of you to share your knowledge.

  • Jared McOmber

    This is a great article! I can’t wait to try this. Thank you for your expertise on this subject and for sharing your knowledge. Just a note, and I may be just misunderstanding here, but if using the 1.2.3 formula (1/6 starter, 2/6 water and 3/6 flour) then the water + flour total should be divided by 5 to get the starter amount, not 6. But thank you again! I look forward to trying this out!

  • Sas

    Thanks so much for this article. Would you use a similar approach for rye starter – 1:1.5 or would you recommend converting it to a 1:1 ratio starter first and going from there?

    • I’m sorry to say I don’t have experience baking with a rye starter so I can’t advise. Good luck and happy baking!

  • Berkley Townhouse

    I am on day 5 of my starter- looking ready, But I had a hard time figuring out where to start when using Commercial yeast vs my Starter dough, Then I found this article!! This is s good start. Thank you!! I just started making my own breads and home, I love it!! I learn something new with every loaf! thanks again, i cant wait to taste the difference.

    • I agree, the great thing about baking your own bread is that it’s a learning experience through and through! You have to be willing to try and try again, and not everyone has the persistence.

  • Vanita Kamble

    Can u plz tell to convert starter recipe into yeast recipe.bcoz I m comfortable to work with yeast.
    also do u hv starter recipe ?

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