## How to account for difference in starter hydration in levain/preferment build with a high percentage of starter in the levain?

Hi Friends!

I feel so embarrassed posting this but my brain is just not processing information correctly. I really need your help.

I use a 100% hydration starter to build a levain (preferment) for one of my recipes. Someone asked me if they can use their 60% hydration starter to build the levain for the recipe. The levain (preferment) uses a high percentage of starter, how would I account for this difference in starter hydration?

Levain Build with 100% hydration starter:

100 grams starter (100% hydration)

100 grams flour

50 grams water

= for a total of 250 grams levain (preferment) to be used in the recipe.

How would I adjust the levain build if the person decides to use a 60% hydration starter instead?

Levain Build with 60% hydration starter:

100 grams starter (60% hydration)

100 grams flour?

50 grams water?

= for a total of 250 grams levain to be used in the recipe.

I know how to adjust the formula when the hydration of the **preferment (levain)** changes, but for some reason, I am having the hardest time for no obvious reason figuring out how to adjust for the difference in hydration in the levain.

Thank you so much for your help!

The short answer is that to get 250 gm levain at the same overall hydration (67%) and % prefermented flour (33%), you'll want

80 grams starter (60% hydration)

100 grams flour

70 grams water

I can come back and elaborate later if you need, but I worked backwards from your levain build, adding half the starter to each of water and flour to calculate the overall hydration and % flour prefermented. Then worked forward with that as the overall formula, subtracted the prefermented flour and 60% of that for the water in the starter. The difference is the new levain build.

Hi Debra,

Thank you so much for your help here. Would you mind walking me through the math as if I am in kindergarten.

I would love to learn from this example so I can apply the methodology to future instances. My brain literally goes offline when I have to work with anything but 100% hydration, which is half flour and half water.

---

Follow up thought-question. Now that the ratio build is a little different, this might impact the length of fermentation for the levain/preferment, do you think it might be better to just use 60% starter in the levain and then adjust the total water and total flour in the final dough formula?

How would you adjust the total water and total flour in the final formula when working with a 60% starter? With a 100% starter, it's easy to do because you just add 50 grams of water to the total water and 50 grams of flour to the total flour. Would love to hear your thoughts and explanation.

I'm going to assume that your target is 250g of levain that has 150g flour and 100g water. So (I hope this table lines up)

Yours Theirs (60% hydration starter)

Flour Water Flour Water

-------------------------- --- -------------------------

Starter 50 50 50 30 ===> 80g starter

Added 100 50 100 ??? ===> 70g added water

--------------------------- ---------------------------------------------------------

Total 150 100 150 100 ===> 250g levain

You could split the amounts differently as long as they all add up to the same totals, but this seems like the easiest way to me. You could change it so they use the same weight of starter, but it's slightly harder to calculate, and in the end wouldn't make much if any difference you could notice in a home baking situation. If they used 100g of starter instead of 80g, the levain mix might start out with a little more yeast and lactic acid bacteria. But growth tends to be exponential once it gets going, and that means the the practical difference would end up being a small amount of time. Differences in the starter and temperature from one bake to the next would be just as big or bidder so no one could really tell if there were a difference because of the 20g difference in starter.

TomP

This is incredibly helpful! Thank you!

So if I balance the levain formula, the total flour and total water of the final dough would be the same!

Using the Percentage of Pre-Fermented Flour PFF method "

Levain flour divided by TOTAL flour (including the flour in the Levain) used in the formula" But I can't seem to figure out how to apply this formula when the starter is anything but 100%. In the case of 100% hydration scenario, I would take 250 grams of levain divide it by 1.5, get 166.67 for the flour and 83,33 grams for the water, and add each of these to get the total water and total flour for the overall formula.But what if I kept the starter at 60%. How would I adjust the total flour and total water of the final dough? How much flour and water would I add to the flour and water of the dough formula? Would I add 62,5g of flour + 37,5g of water from the 60% hydration starter plus the flour and water from the levain, in this case 50 grams of water and 100 grams of flour, the total would than by 162.5 grams total flour and 87.5 total water?

If anyone has more literature or examples of how to use the Percentage of Pre-Fermented Flour PFF method "

Levain flour divided by TOTAL flour (including the flour in the Levain) used in the formula" I would be super grateful. I learn best from examples. I have a pretty large bread baking book collection but I am having issues finding relevant information regarding PFF.Home bakers like Maurizio (the perfect loaf), doesn't include starter in his pre-fermented flour percentage (he says "you may also wonder why the flour and water used in the sourdough starter are not included in the total weight of flour and water in the formulas in this book"). Jeffrey Hamelman's book bread was helpful page 445, but they don't have an example with sourdough starters and different starter hydrations.

I couldn't find an example where someone walks you through the process of doing the pre-fermented flour percentage with the inclusion of starter which I believe is what most professional sourdough bread bakers do.

How to go about it depends a bit on where you start from. As long as you start from a known place, you can work the same way.

For myself, I don't bother about the amount of "prefermented" flour. I don't mean there is no place for it, but only that for my at-home baking it adds a level of complication without helping me with anything very useful. Of course, I have a rough notion what the PFF number might be. I tend to use about 30% of the flour weight for my starter. The starter is usually around 100% hydration. So close to 15% of the formula's flour comes from my starter. Suppose I used equal weights of starter and added flour:

flour water

starter 50g 50g ===> total 100g of starter

added flour 100g

total 150 ===============> 50g out of 150g is prefermented flour

It sounds like you may be getting a little jumbled up when you think about starting with a given amount of starter but it's not at 100% hydration. Then you would make use of the concept of the "yield" of the dough. The yield is the weight of dough for a given amount of flour. Let's use two hydration levels, 100% and 60%:

hydration flour water total dough

---------------------------------------------------------

100% 100 100 200 ===> yield = 2

60% 100 60 160 ===> yield = 1.60

How to use this idea? Say you know that a recipe says to add 100g of starter, and that starter is at 60% hydration. Then:

starter flour water (60% hydration)

-------------------------------------------------------------------------------

100g 100/1.60 = 62.5g 62.5 * 0.6 = 37.5g

Now you can plug those numbers into a table like the one I posted for the total levain.

You can make up a little table of yields to refer to. The weight of the dough equals the flour weight plus the water weight (just ignore any possible additions because we are thinking about starters and levains that usually don't have inclusions like nuts, mashed potatos, or whatever):

W = F(1 + H) (H is the hydration: 60% hydration means that H = 0.60)

Divide by the flour weight to get the yield Y:

Y = W/F = 1 + H Example for 60% hydration: Y = 1 + 0.60 = 1.60

I made up a little table for myself:

Hydration, % Dough weight flour weight

-------------------------------------------------------------

60 100 62.5

65 100 60.7

70 100 58.8

75 100 57.1

80 100 55.6

I hope this is useful.

THANK YOU SO MUCH! This means so much and it is more helpful than anything I found in my 20+ bread books I have at home. I am saving this for reference. Do you have any recommendations for learning more about this topic? I found this post https://www.thefreshloaf.com/node/64600/levain-calculation which is helpful but doesn't provide a lot of examples or hydration variations. I understand it so much more after your explanation but definitely need to educate myself more on the subject, PFF.

I know it is hard to believe but I actually have a lot of formulas that use very high starter and levain percentages because I like to bake at ambient temperature which has fallen out of fashion in the sourdough baking community.

If there is anything I can do to return the enormous favor you did for me by explaining in such detail please let me know!

: )

I don't have any recommendations for more reading. Just remember that various authors may define things differently. For one example, should the hydration number include the flour and water in the levain/starter or not? If you are computing how much water to add to the flour + starter, then no, it shouldn't:

Recipe

----------

300g (100%) - flour

200g (67%) - water ===> 67% hydration

90g (30%) - starter

But the total water as a fraction of the total flour is probably more useful for knowing how the dough will handle:

Recipe

---------

flour 300g

flour from starter 45g

total flour 345g

water 200g

water from starter 45g

total water 245g

Overall hydration

------------------------

245/345 = 71%

If you are like me, you will like the first form better! It tells you how much of what to add, and it is easy to scale for different amounts of flour. So what is the meaning of the term "hydration"? It can be used either way, so you have to read carefully to be sure what an author means. Either way is fine, one way might be better for you.

If you are working in a bakery and you need to produce 1.5-pound loaves, you will want to start from loaf weight and apply the yield to figure out how much flour to use. Me, I know that 300g of flour will give me an approximately 1-pound loaf, and that's close enough for my purposes.