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Bakers Percentages Levain Calculator

worthog's picture

Bakers Percentages Levain Calculator

Hi fellow bakers-

I maintain a 100% hydration starter, and often find myself using recipes that specify 80% hydration levain.  So after many articles about bakers math/percentages, a few things seem apparent when I convert recipes:

- For completeness, pre-fermented flour (PFF) and water in the levain should be included in bakers percentage calculations.

- When using a levain with a different hydration percentage than called for in a recipe, PFF and dough hydration percentages must be maintained.

- If I add an adjunct not called for in the recipe (e.g. nuts or dried fruit), say 50g of nuts to an 800g total dough weight, then I must decrease all other ingredients by 6.25% (50/800) to maintain the total dough weight.  By doing this, the math shows that my PFF bakers percentage will be maintained.  

Assuming the above is correct, I built a calculator that takes as input flour, water, levain mass and levain hydration (recipe and your own), then builds bakers percentage tables for the existing and modified recipe.  Appreciate any feedback on whether I got this right.  I'll modify the calculator to consider adjuncts and scaling up/down in some future version.  

Here's a screenshot of bakers percentage tables for a recipe calling for 100% hydration levain and adjustments if using an 80% hydration levain.  Note that only starter and water amounts changed in the Adjusted Recipe.  


Thanks in advance for any feedback.


proth5's picture

which articles you read on Baker's percentages, but you need to read the technical articles from the Bread Baker's guild of America (at that are available to non-members.

Although I am sure that your calculator is great, you make things hard on yourself by not using the factors of "percentage of flour in the preferment" and the proper expression of the composition of the total dough, preferment, and final dough. By doing this you eliminate the need to change percentages for any add ins.

Feel free to ignore this - many people do.

You asked for feedback. This is mine.

worthog's picture


Thanks for the feedback and the referral to  I will review those technical articles to see where I might have some misunderstanding about the "proper expressions of the...dough." I might have made this harder than it should be, but I think the calculator sort of distills some of the many comments I've seen in other threads, and does capture  some definitions of how to compute baker's percentages.  ;-)

I would have guessed that "percentage of flour in the preferment" is the ratio of PFF to total flour (baker's percentage), which I do include in my table. Your comment piqued my interest, so I'll look for what you might be referring to, particularly.

Thanks again. Much to learn.

proth5's picture

Read the technical articles.

Yes, you have the percentage of flour in the preferment in your numbers, but then you also use the percentage of total water in the preferment. The expression of the percentage hydration of the preferment is left in the "comments" section rather than being introduced as a part of the formula.

I see this in a lot of popular baking books and it just isn't right. Read the BBGA technical articles. Yes, there are a lot of comments on a lot of threads and a lot of confusion in them. That is, frankly, because they start from a poor foundation. Writing formulas by expressing the preferment as a single ingredient and as a percentage of flour in the overall formula is just - wrong. A lot of people do baker's percents - wrong. A lot of books go to publishers with the baker's percents being - wrong. A lot of beautiful blogs with beautiful bread exist with the baker's percentages being - wrong.

If you want to write formulas any which way, feel free to do so. But if you write anything more than a simple flour, salt water, yeast, plus preferment, you will watch you system become cumbersome.

Start with the composition of the overall formula - what, when all is mixed is the hydration of the dough, what are the percentages of additional ingredients? These will not change depending on the hydration of the preferment. They shouldn't change. It is how people experienced with formula development and analysis understand the formula.

Then using the percentage of the flour in the preferment, write the formula for the preferment. Is it 100% hydration? 60%? - that should be expressed in the formula.

Then you do a simple subtraction to get the composition of the final dough which will then include the preferment as an ingredient. Optionally, the percentage of the preferment can be expressed as a percentage of the flour in the final dough, but it isn't required.

Sorry to be curt, but I have written the instructions for properly doing baker's percents on these pages so often that I get discouraged because every new generation of bakers feels a need to invent their own. It has been done for you. It works very well and with formulas that are more complex than you can imagine. I got into a fight with a cookbook author on this very topic when he expressed to me that he had to do things wrong because his formulas were complex. I referred him, as I refer you to the BBGA technical articles. I'm in the acknowledgements in his book.

Read the BBGA technical articles.

worthog's picture


I started digging into the BBGA articles and I have to say that they were a revelation.  Most interesting to me is that the "seed" ("...the portion of the sourdough or levain system used to inoculate the "starter"...) is treated as a separate, discrete ingredient.  It certainly simplifies the math, so one doesn't have to obsess about converting levain hydration percentages from one recipe to another.  

I will create a calculator based on the table below found in the The Bread Bakers Guild of America Formula Layout Standards Part II (orange fields are inputs):


I've browsed through a lot of baking books and read a lot baker's math info online.  This is the first time that I encountered this particular approach, but it absolutely makes sense.  And you're right, most authors don't conform to this method when computing baker's percentages.

Besides the article I mentioned above, anything else you'd recommend to gain a better understanding of this topic?

Thanks again for your feedback.  Very helpful.  Looking forward to learning more.



proth5's picture

is very thorough. With a little practice the system becomes very easy to use and it is very versatile. You can use it not only for bread, but for pastry and chocolate. (And I will add - Two people on TFL in one day have admitted that I might know what I am talking about. That's a record! It won't bring me back as a regular poster, but it's a nice feeling.)

There are baking books that use exactly this approach ("Bread" and "Advanced Bread and Pastry" spring to mind), but they tend to be the kind of books that are more oriented towards the "professional" level baker and are often neglected in home baker conversations (They also don't rely heavily on "food styling" to be the eye candy that popular books seem to have to be. They are more "mind candy."). "Advanced Bread and Pastry" is a major purchase commitment, but because I also do pastry (and chocolate) it has become my go to source of formula inspiration. (And yes, "Bread" was my go to book for bread for many years, but it is only about bread.)

I do have a little tip that I'm not sure the technical article highlights.

You will notice that the total percentage is calculated for the overall formula. This gives rise to a very useful equation:

Total dough weight = total flour weight X (total percent/100)

This is how the system is designed. So if you do your spreadsheet correctly, you can calculate:

Total flour weight = total dough weight/(total percent/100)

This means (if you have done the spreadsheet correctly) that you can enter the total desired dough weight and it will flow seamlessly through all the rest of the calculations. Most of the incorrectly represented formula formatting that I have seen does not have that feature - which is of great utility to the baker. (And you really didn't think you were the first person to put formulas in spreadsheets, did you?)

Also, with the above equation you can calculate how much dough you can make with a given quantity of flour. I normally don't find that useful, but in these days of flour shortages, it might be handy. But only if you have used the right formula formatting.

I would also add that these days for the BBGA, the weights of the ingredients for the final dough are used to calculate percentages (against the weight of the total flour in the final dough). I really don't know why this is useful, but someone decided that it needed to be done. If anyone can explain to me why these percentages are useful I am willing to listen and learn,

Oh, and by the way, if you design your spreadsheet for more than one flour (as the technical article does go into), you must add a line for "total flour" and "total flour" is always 100% (for bread...)

Good luck. Learn a thing right and it will really pay off.



worthog's picture


Again, my thanks for your feedback.  You took me down an unexpected but very enlightening path in my bread baking journey.  Some comments about your post:

  • I don't quite understand what you mean by this, "...these days for the BBGA, the weights of the ingredients for the final dough are used to calculate percentages (against the weight of the total flour in the final dough)."  My guess is that some variations of the BBGA calculator have percentages in the "Final Dough" column, which the screenshot above doesn't include.  Is that correct?
  • In playing around with the math using the BBGA method, total dough weight, water amount, and flour amounts (either value or percentage) are the "starters" (pun intended).  Everything flows from there.

I'm very happy to be learning this method, but it was also good to understand the 'conventional' or common methods that people use to calculate baker's percentages.  True even if only to better realize the benefits of the BBGA method over other approaches.  I'm wondering if the BBGA method is used on other continents with rich bread baking histories.



proth5's picture

On your first point your assumption is correct - it is not in the technical article, but recently the standard was changed to include an extra column after the final dough. Again, I don't know why this is useful. It is totally optional.

Yes, if you know total percent and final dough and final dough weight, you can calculate total flour weight and so forth. Once you know the total flour weight and the percent of total flour in the preferment, you can calculate all other weights from the percents.

Baker's percent calculations do not really vary - people pretty consistently calculate percents of ingredient weights against flour with flour always being 100%. What varies widely is what is included in the formulas and how they are formatted. The BBGA standard was created so that a consistent format could be used no matter how complex the formula. It has held up well.

I took a quick look at my French baking books. Two of them do not calculate baker's percents at all  "Le Gout du Pain" calculates baker's percents as described above and does (inconsistently) include the percent of total flour in the preferment and the convention of using total dough, preferment, and final dough. Of course "Le Gout du Pain" pre-dates the BBGA standard, by, oh, a lot, but I have no doubt was a part of the inspiration for it.

I need to not post to TFL anymore, so I won't be answering any more of your question, I'm sure other people can help you. If you really think I am the only one who can help, send a PM.

idaveindy's picture


DanAyo and isand66 both use spreadsheets that give both grams and percentages so you get a clear picture of what is a percentage of what, even though you don't see the underlying spreadsheet formula.

See the OP of the two latest community bakes (ciabatta is the latest, and the baguette previously) for Dan's spreadsheet format.  He puts grams and % in neighboring columns.

isand66 has a blog here:

and uses 2 separate spreadsheets for grams and %.

Hope this helps.

worthog's picture


Thanks for the referrals to the DanAyo and isand66 blogs. Both reinforce the efficacy of the BBGA approach to baker's percentages. And it's always fun reading content from authors who have an obsession for all-things-bread. Some observations from their respective blogs:

  • isand66 doesn't consistently include the water content in the seed starter. I'm guessing that it becomes important if one uses a high percentage of seed starter in the levain. The BBGA article doesn't consider seed hydration in it's method. Any thoughts on that from you or others who might be following this thread?
  • DanAyo's post, Tip - Starter vs Levain, is very helpful in terms of methods for building the levain. So even though one might be aware of the difference between a starter and a levain (I was), the post did help me to understand better that the alternative methods of building a levain are OK.

A general observation: A single spreadsheet which tries to capture all variations of baking bread (straight dough all the way to those having multiple preferments) would be unwieldy.  Has anybody encountered one that works for most bread types?

idaveindy's picture

spreadsheet is flexible enough to cover both pre-ferments and straight dough.

The preferments are in colums, and yeast is in a row.  It may take some text explaining what portion of a levain build "n" goes into the next levain build "n+1".

I think it can work because I seem to remember some of his spreadsheets being a combo of yeast and sourdough preferments.

worthog's picture

Hi Bakers-

After the very helpful feedback in this thread, and based on a study of the BBGA standard I updated the online calculator at to conform as much as possible to that documented standard using TDW and percentages as input.  I know it's anathema to some, but I break with the standard by updating total formula based on preferment values (and provide a footnote where I've done so).   On the site, you can also find a more conventional calculator where I calculate baker's percentages based on ingredient weights.  Here's sample output from the calculator, consistent across the 3 calculators that I have on the site:

Baker's Percentages Table

Any feedback is welcomed.