Baker’s Percentage Tutorial, Part 4

This final installment in the Baker’s Percentage tutorial series concerns breads that are made with preferments. (A preferment is a poolish, biga, sponge, sourdough starter, etc., where a portion of the flour is fermented prior to the mixing of the final dough.) If you missed the first three parts, you’ll want to read them before diving into this one. An index of the entire tutorial is here.

A preferment can be thought of in different ways. On one hand, it is a dough unto itself, and it has a BP formula all its own. But a preferment is also an ingredient in the final dough.

Look at this formula for baguette dough made with a poolish. The blue table shows the formula for the final dough, scaled to make 2340 g of dough. The yellow table shows the formula for the poolish, scaled to make 936 g, the amount needed for the final dough. Note that the formula for each part is based on the amount of flour needed for that part. Also note that the poolish is listed as an ingredient in the final dough formula.

Poolish Final Dough
Ingredient % Grams % Grams
Flour 100% 468 g 100% 900 g
Water 100% 468 g 52% 468 g
Instant Yeast 0.06% 0.3 g 1% 9 g
Salt 3% 27 g
Poolish 104% 936 g
Total 200% 936 g 260% 2340 g

The formula for the final dough might seem at first to be a bit unbalanced. 52% hydration — is this a very stiff dough? (Remember hydration is percentage of water, and 52% is more appropriate to a bagel than a baguette.) 3% salt — is that way too much? (2% is usually about right.)

Ah, but — remember that poolish! It’s an ingredient in the final dough just as the water, yeast, and salt are. But it’s no ordinary ingredient, because it brings 468 g of flour and 468 g of water to the overall composition of the dough. If we factor in those contributions, things make a lot more sense.

When a dough has preferments, it’s helpful to look at the total formula (sometimes referred to as overall formula). The total formula gives the total amounts of all the “raw” ingredients, including those contributed by the preferment(s). In a total formula, the preferments are not listed as ingredients themselves, but their component ingredients are factored in.

For the baguette dough, we look at each ingredient and add together the number of grams contributed by the poolish and the grams contributed in the final dough to yield the total weight of each ingredient in the overall dough composition. This is the green “Grams” column. The green “%” column is then calculated by converting these amounts to a BP formula (see Part 1 if you forgot how to do this).

Total Formula Poolish Final Dough
Ingredient % Grams % Grams % Grams
Flour 100% 1368 g 100% 468 g 100% 900 g
Water 68% 936 g 100% 468 g 52% 468 g
Instant Yeast 0.68% 9.3 g 0.06% 0.3 g 1% 9 g
Salt 2% 27 g 3% 27 g
Poolish 104% 936 g
Total 171% 2340 g 200% 936 g 260% 2340 g

I find total formulas useful because they help you quickly assess the overall dough makeup (see Part 2). However, the final dough and preferment formulas are more useful when you’re actually mixing or want to scale the dough. (Surprisingly, many books that go to the effort to explain BP give either total or final dough percentages. The only book in my library to give both is Rose Levy Beranbaum’s The Bread Bible. Rose, you have my undying appreciation and admiration!)

Now let’s analyze the formula for a bread in which the preferment is an 80%-hydration sourdough starter. The final dough formula (scaled here to make 1110 grams of dough) is:

Final Dough
Ingredient % Grams
White flour 80% 400 g
Rye flour 20% 100 g
Water 66% 330 g
Salt 2% 10 g
80%-hydration sourdough starter 54% 270 g
Total 222% 1110 g

The recipe doesn’t specifically say how much flour and water are in the starter, but we can figure that out by expressing the starter as its own formula. A starter is just flour and water, so an 80%-hydration starter has this BP formula as shown in yellow:

Starter Final Dough
Ingredient % Grams % Grams
White flour 100% 80% 400 g
Rye flour 20% 100 g
Water 80% 66% 330 g
Salt 2% 10 g
80%-hydration sourdough starter 54% 270 g
Total 180%
222% 1110 g

In Part 3 we saw how to make a given amount of dough from a BP formula. Applying that here with the needed 270 g of starter, we can calculate the grams of flour and water in the starter:

Starter Final Dough
Ingredient % Grams % Grams
White flour 100% 150 g 80% 400 g
Rye flour 20% 100 g
Water 80% 120 g 66% 330 g
Salt 2% 10 g
80%-hydration sourdough starter 54% 270 g
Total 180% 270 g 222% 1110 g

So the 270 g of starter contributes 150 g of (white) flour and 120 g of water to the final dough. Now we can calculate the total formula as we did with the baguette dough above, and we can see that this is a 69%-hydration dough whose overall flour content is 85% white flour and 15% rye:

Total Formula Starter Final Dough
Ingredient % Grams % Grams % Grams
White flour 85% 550 g 100% 150 g 80% 400 g
Rye flour 15% 100 g 20% 100 g
Water 69% 450g 80% 120 g 66% 330 g
Salt 1.5% 10 g 2% 10 g
80%-hydration sourdough starter 54% 270 g
Total 170.5% 1110 g 180% 270 g 222% 1110 g

CommentsLeave a comment

  1. says

    Tanna, it does take some getting used to and I think it gets easier with practice. I’m glad you find this helpful.

    Bart, it would help me to know specifically what you think is wrong. Thank you!

  2. says

    Susan, I loved this series. I’m a fan of math myself and I dig reading through stuff like this over and over. Thanks for taking the time to put these together. It’s so helpful (and entertaining) to take in information from different types of sources, and a blog bp tutorial series is definitely something new!

  3. says

    As usual, a very clear and informative article. I was raised on that basic three section formula and have written out my recipes in that way for decades. I’ve never been lucky enough to attend the SFBI (although my wife and I have been talking about working it into a vacation) so I’m not sure what Bart means. When I apprenticed as a young boy that’s how the old timers did it. We always used a starter (100% hydration) and although I eventually didn’t have to look at a formula, writing out a new one was always in three parts.

    I’m always willing to learn new things, so if someone can explain the SFBI method, I’d appreciate it.


  4. says

    rainbowbrown, thanks for the kind and encouraging words. I enjoyed doing it!

    Dave, thanks for the confirmation that I’m not out in left field. I have attended five courses at SFBI (including the one Bart mentioned) and I’m not sure how anything here is at odds with what they teach, so hopefully Bart will return to explain where he thinks I’ve gone wrong.

  5. says

    Susan, excellent tutorial!
    I’d like to mention that the best discussion I’ve seen of Baker’s Percentages is in the new book by Michel Suas, “Advanced Bread and Pastry.” The book has an extensive appendix on Baker’s Percentages. Moreover, before the chapter on bread formulas there is an excellent section on how to develop a bread formula.
    Another excellent source on Baker’s Percentages is Jeffrey Hamelman’s book, “Bread”.
    Both books are very highly recommended.

  6. says

    Boaz, I don’t have the Suas’ book yet but I will soon. When I took my first courses at SFBI they were in the midst of writing/editing/photographing for the book so I’m eager to see the finished product. You’re right that Hamelman has an excellent discussion of BP. I wish he had included final dough percentages for his formulas — he argues that they are confusing without offering useful information; I’m not sure I agree with that, but of course everyone decides for themselves what is useful. That said, “Bread” is my favorite book and I second the high recommendation.

    Donna, you’re welcome, I hope this addresses the question you asked on the Part 3 comments.

  7. Kris says

    Thanks for the tutorial. I was familiar with a vague concept of BP, but I’d never actually used them. The exercises were a good confidence-booster, and caused me to reminisce about my school days years ago! I loved my Math classes.
    Great job!

  8. says

    Hi! great tutorial : )
    I have always avoided the bakers percentage, but I was curious of how much hydration is good to have for particular bread like pizza, bagel, regular french bread and such. So I understand how important the bakers percentage is now.
    I’m still not used to the baker’s percentage, but will re-read this when I need help. Thank you !

  9. says

    Hi Susan, Thanks so very much for this tutorial. Sounds very coherent to me! What’s up with Bart? It’s so easy to yell and flee. Anyway, I’m really happy to finally understand all that and I’m no math wizz. So, thanks for taking the time and making it clear.

  10. says

    Kris, thanks for letting me know this was helpful to you!

    monchy, you are welcome. The concept of hydration come up over and over again so I think this is one of the most useful applications of BP.

    Jane, you’re welcome and thanks for stopping by. I always enjoy your contributions to The Fresh Loaf!

  11. Eggy says

    THANK YOU for these tutorials! I’m rather brand new to baking as it is and quite honestly I was getting frustrated not knowing how to make a required starter for recipes I’ve wanted to make… Your tutorials are very informative and helpful!

  12. Muhammad Khaki says

    Thanks for this! We’re just starting to introduce theory and practical lessons in our high school and since I get the honor of introducing this new subject, this is a perfect way to tap into a culinary lesson with a broader view of making it fun, interesting, and exciting to teach. Well, that comes from a chef’s perspective but I’m sure my students will love it anyway.

  13. says

    hi , i am desperately looking for a easy 100% rye bread recipe – given in BP so that i can increase the recipe as the need arises . i am new at baking lots of loaves at one time , other recipes that were in BP I HAVE SUCCESSFULLY baked . what is the amount of wet starter needed if dough weighs 800g ?
    from – hermanus south africa

  14. Greg says

    Susan Breedt,

    Do you already have a recipe that you like that is NOT in BP? Converting shouldn’t be terribly hard, especially if you have a good kitchen scale. I understand your frustration though – I like to convert recipes to whole wheat, and it JUST DOESN’T WORK when you only have a volumetric template.

    Anyway, the “standard” for flour is 140g per volumetric cup. This does depend on your flour, though. The other volumetric parts of your recipe, you can zero your scale and weigh out. Once you have everything expressed as a weight, you can calculate the ratios and scale accordingly. I’m not sure that you can turn a volumetric recipe directly into a BP, so be careful with that. Although you could try it, and see what happens! (You would need to unify the units first; 3tsp = 1 tbsp, 16 tbsp = 1 cup, etc.)

  15. Gabrielle says

    I thought the whole tutorial was clear, and the exercises most encouraging (I learn the best with practice)… even with my minimal math skills. Thanks for taking the time to point me towards this excellent (and now bookmarked) resource!

  16. Francesca says

    This was so helpful!
    One question though – once I’ve determined the hydration of the dough, how do I adapt that recipe to accommodate a starter of a different hydration, i.e. the recipe calls for a 100% hydration starter and I’ve determined the ultimate hydration of that dough with the 100% hydration starter, but I want to use my 200% hydration starter in the recipe????

  17. Wel says

    hi Susan,

    thank you so much for this… :-)

    lost my notes on baker’s percentage from my comprehensive baking class that i attended several years back…

    you are such a great instructor… thanks again… :-)

  18. says

    Excellent instruction Susan. Anyone following it will surely elevate their artisan skills as a baker! Mine have already skyrocketed after 2 practice exercises! I honestly understand the math and why it works. It is a great thing to have a teacher open your understanding on something that seemed so complex. Too bad this did not happen much in grade school math classes for me. I would have certainly taken more. Thanks again!

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