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Why is Leaven not calculated in the Hydration Percentage?

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SJonesColumbus's picture
SJonesColumbus

Why is Leaven not calculated in the Hydration Percentage?

First post with a quick question: why is the amount of leaven in a bread dough not considered part of the hydration percentage?

 

I'm working with a dough that is 800g Bread Flour, 200g Spelt, 500g water, that also has 800g Poolish (400g Bread Flour, 400g water, pinch yeast). I make the poolish the night before and then add it to the dough in the morning, but additional yeast is added to the dough so it doesn't really act like a leaven, per se. The Tartine charts show that they do not include the leaven in their calculation for hydration percentage. I'm trying to "think like a baker" and compare the hydration percentage of this dough vs. many others.

 

Calculating the Hydration Percentage based on Tartine, without factoring the Poolish, would be 50% (500g / 1000g). If I calculate with the poolish, then the Hydration percentage seems to be 64% (900g / 1400g). In reality I know that I'm only adding equal parts flour and water, but the arithmatic charges significantly.

 

What am I missing? This question seems so basic that I'm sure it is obvious. Thanks for the help.

Les Nightingill's picture
Les Nightingill

I seem to recall when this has come up before, we concluded that Chad Robertson excludes levain from the hydration calculation for simplicity, and because, for his formulae, the difference is small. This may not be the case for other formulae, as you have found. My suggestion would be to include it.

Les Nightingill's picture
Les Nightingill

I checked the BBGA guidelines to see if they mention this.

They include preferments in the final dough ingredients calculation. Surprisingly, however, they never seem to actually calculate a final dough hydration number.

Mini Oven's picture
Mini Oven

is fully hydrated flour and will not give up enough water to hydrate additional flour well.  So hydration has to be increased or risk very lumpy dough. 

The math is 50% but the poolish is 100% and it will not give up half if it's water to hydrate the rest of the flour to 50%.  So more water is needed.  Which isn't bad from the handling point of view.  You get a higher hydration dough with a lower hydration dough feel.  (But only if the poolish is not over-fermented.)

proth5's picture
proth5

Because it is all very simple and straightforward. And important to understand.

The pre ferment is included in the calculation of the hydration of the overall formula.

If you look at the BBGA (Bread Baker's Guild of America) standards as referenced above, you will always see both the flour and the water used for a preferment included in the "overall formula" weights and bakers percentages.

The hydration of the preferment is also expressed as a bakers percent.

What is not included, if the preferment is "sourdough" based is the hydration of the "seed" or the starter used in the pre ferment . This is a valid simplifying assumption because the amount of seed is usually small in comparison to the total dough.

Given what is calculated above, we know the final hydration of the dough we will eventually mix/shape/bake and the hydration of there pre ferment we need to mix. Both indicate things to the baker. When you "think like a baker" both of these are important.

In the BBGA standard, percentages are not calculated on the ingredients for the "Final dough." These are the ingredients that will be added together with the preferment to create the dough that we will mix/shape/bake. Some bakers like these percentages, but they are problematic as ingredients are being added to a mix of flour/water (the pre ferment) and percentages are either distorted or are the same as the "overall dough."

It is an elegant solution to expressing formulas. I have tried others and this one provides complete information in a succinct way.

The impact of a pre ferment on the overall hydration of the dough is important. Frankly, authors who do not use the above conventions fail to hold my interest, so I don't know much about them. I try not to write about things I know little about.

But if you are talking the BBGA standard, what I have explained above is correct. The pre ferment always is included in the hydration calculation of the overall formula.

Mini may be thinking about "soaker water" not being included in the calculation of the hydration of overall formula because it is absorbed by the soaker material (making the soaker "hydration neutral"). That is another diverting topic in and of itself...

SJonesColumbus's picture
SJonesColumbus

This has all been very helpful. In short, proth5, you're saying that the hydration percentage of the bread in my example is 64% (900G / 1,400G)? I want to make sure your explanation is totally clear.

 

thanks again everyone!

proth5's picture
proth5

Because it does seem that there is confusion on this topic:

Your total flour is 800g(bread)+200g(spelt)+400g(bread in the pre ferment)  = 1,400 g (as you said)

Your total water is 500 (in the final mix) + 400 (in the pre ferment) = 900g (again, as you said)

Overall formula hydration is 900/1,400 or 64%, you get an "A."

Let's show some important other calculations:

Percent of total flour pre fermented: 400/1400 = 29%

Percent of bread flour pre fermented: 400/1200 = 33%

Hydration of the pre ferment: 400/400 = 100%

Percent of overall formula flour that is spelt: 200/1400 = 14%

Percent of overall formula flour that is bread flour: 1200/1400 = 86% (note how these two add up to 100%)

Give me the percentages of salt and yeast and I have completely expressed your formula. And I know quite a bit about it.  You are making a liquid preferment and prefermenting about an average amount of the total flour. You will be creating a moderately hydrated dough, again about typical for a freestanding loaf. The amount of spelt will have some impact on the dough, but will not significantly impact the handling qualities brought by of the bread flour.

Sorry for the overkill.  I think you have this well in hand.

Hope this helps.

JacquelineColussi's picture
JacquelineColussi

Beautifully expressed, proth5!

proth5: [The BBGA formula format] is an elegant solution to expressing formulas. I have tried others and this one provides complete information in a succinct way.
I agree. Complete information about a given bread formula is the baseline, which enables a baker to creatively think about another baker's bread (or one's own)—and from there attempt to replicate that bread, or tweak it, or adapt it to one's own goals.  There's a question I would like to ask you. Above, you shared some "important other calculations," one of which is:
Percent of bread flour pre fermented: 400/1200 = 33%
What does this percentage (33% in this case) tell you about this formula, that the formula's other percentages cannot? I find meaning in each of the other %s expressed in the BBGA formula format. But this particular number's meaning eludes me yet. I'm interested in the meaning other bakers find in this number. (As to-date neither Dado nor I have found this particular % meaningful, we haven't implemented support for it in BreadStorm. But this could change....)


All best wishes,
Jacqueline

proth5's picture
proth5

You are correct, this number by itself tells you little.

But combine it with the number:

Percent of spelt flour in the preferment: 0%

And you know which flour to put in your pre ferment mix. This is important since then I know I have an all white flour pre ferment.

In a sense, the zero percentage is superfluous since, if you calculated weights from these percentages you would end up with the correct components in your preferment mix. So I do think the first number (33%) has some importance. I've had it in my spreadsheets for years. I'm an engineer and doing spreadsheets is "mind candy" for me.

I have meant to look at BreadStorm, but you know how it goes. If you have something that works...

Hope this helps.

Pat

BetsyMePoocho's picture
BetsyMePoocho

Jacqueline,

I do not possess to command the expertise or knowledge that you and proth5 add to this discussion.  What I would meagerly add is the "percent of bread flour pre-fermented" number is this... It provides me some indication of how the pre-ferment should bias the flavor in the final dough.

(Of course my pre-ferments are controlled, temp at or below 72℉, and for 12 to 14 hours max.)

Oh, I just spent the last hour or so using your "BreadStrom" program.  Sweet job you have done.  I think that the most difficult thing the "new" baker has to become intimate with is the Bakers Percent / Bakers Math.... and this program is a very good tool...!  (But kinda pricy.)

This entire thread has been a joy to read and I have learned a lot.....

Thanks

 

 

Mini Oven's picture
Mini Oven

and can't read straight.  I was thinking there were two recipes one a straight dough with 50% hydration and another with 64% and a poolish.  My mistake.  Sorry.  But it did get you out of the woodwork, Pat!  Nice seeing you!  :)

proth5's picture
proth5

I knew you knew better.  Just like a marmot, sticking my head up - saw my shadow - and back I go...

jkandell's picture
jkandell

"What is not included, if the preferment is "sourdough" based is the hydration of the "seed" or the starter used in the pre ferment . This is a valid simplifying assumption because the amount of seed is usually small in comparison to the total dough."

Another practical reason to not include the chef in the hydration:  in a common starter maintenance routine, one takes out about that much from the levain to create a new chef for the fridge.

proth5's picture
proth5

up to a point.

Depending on one's maintenance routine, one mayor may not be taking an equal amount of seed out to maintain the culture. I tend not to rely on taking a portion of the pre ferment out of the formula to perpetuate the culture. Some people will say "wasteful - oh, the shame, oh, the horror"  (and I won't give my standard lecture on "what is waste?" just be assured I have been condemned on these pages often enough on my maintenance practices to be a bit defensive) but I will never bake off my culture by accident and that means something to me.

But I was pondering more on this scenario: I routinely maintain a liquid culture. For a particular formula, I have decided on a firm pre ferment. I can use the liquid culture as seed in this pre ferment without going through the math to adjust the water in the pre ferment. It just isn't needed because there are just a lot more variables in the whole bread making process. (OK, yes, I did have a spreadsheet that made adjustments based on seed hydration, but it was just to satisfy my desire to do the math...) In this particular case, one might not take out an equal amount of the pre ferment to perpetuate the culture...

Either way - it's all good.

BetsyMePoocho's picture
BetsyMePoocho

proth5,

Wow,,,, Now I finally feel confident in most of my recipes....  I have tried to "plow" through the BBGA several times, but being a little slow on the uptake I've only gleaned the high points.  Which sometimes got me in trouble.

Your "Just lay it all out" is like the sun burning off the "fog"..... Laying it out is what I've been doing, but never really knew if my methodology was correct.

Wow,,, what fun!  Large Thanks....

 

proth5's picture
proth5

I could help.

Baker's math is such an illuminating tool.

Thanks

David Esq.'s picture
David Esq.

If it is useful, Diagram 3 from BBGA for RUSTIC SOURDOUGH WITH THREE FLOURS, A CRACKED WHEAT SOAKER AND A YEASTED PREFERMENT, is converted to a Google Docs Spreadsheet here.

Only difference is I used grams instead of kg for my measurements.

 

BetsyMePoocho's picture
BetsyMePoocho

David Esq.,

Nice job on the spreadsheet you did.  That took some time and effort!!  Like proth5 said... "spreadsheets are mind candy".  

I've also put one together and now I wonder why I waited so long to do it......

 

 

adri's picture
adri

Simple answer: You do. Just Chad Robertson mad a mistake, like every author does. I believe in a 2nd edition he'll have it corrected.