Incorporating the Starter into your Bakers Percentage


Hi all,

I have a query for those who may have answer for me.

When i work out my ingredient weights using BP,  do i need to incorporate the flour and water from my Levain into my BP?

i use a 100% hydration starter.

For Example: 

At present if i was to bake 2 loaves at 1000grams each, Total weight 2000grams my BP would be:


Water (Hydration)70729

But should i be adding the 104 grams of flour and 104 grams water from my starter into my ratios, because in theory my Total four weight will be 1146 grams (1042 grams + 104 grams  half the starter ) and my water weight will be 833 g (729g + 104g, Half the starter). Because if my maths is correct the hydration is around 73%. God i hope this makes sense to someone out there in the know.

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farinam's picture
farinam 2013 May 19

Hi gamby,

As I understand it, Bakers percentage is merely for ease of scaling ingredients from one recipe size to another and, for sourdough, the levain/starter is just another ingredient.

Where the content of flour and water in the starter becomes important is in the calculation of the hydration of the final dough.  If it is a yeast recipe that you are converting to use a sourdough levain, then, if you are to get the hydration right you will have to make allowance.  If it is a sourdough recipe, then it will only be the difference between the specified starter and yours that will be of significance.  With a bit of calculation, it is possible to adjust the starter hydration during the feeding stage and I have published a spreadsheet that will allow you to do this.  if you check my blogs you will find it.  There is also one for recipes as well that also has a scaling function.

Good luck with your projects.


gamby 2013 May 19

Thanks Farinham,

It is a sourdough recipe, so as i thought, if i adjust my leavain hydration to the same hydration as my final dough mix.

Once again, thank you for your advice.


farinam's picture
farinam 2013 May 19

Hi gamby,

No, I was suggesting that you could adjust your levain hydration to match the hydration of that specified in the recipe.  If the base recipe calls for a 100% starter BP and your starter is not 100% hydration then you should take an amount of that and when you feed it in preparation for making your dough you should add flour and water in the required amounts to end up with the required mass of levain at 100% hydration.

As an example, if your scaled recipe calls for 400g of levain at 100% and your starter is 65% then you could take 180g of starter and add 90g of flour and 130g of water.  When that has proved you add it to the scaled masses of flour and water to make your dough.  The other way to do it is using the staged adjustment where you start with only a very small amount (a few grams) of the starter and build it up in stages over 24 or so hours feeding with effectively one to one flour and water following a mass increase schedule such as the one given by my progress build spreadsheet.  This sort of adjustment can be made either way (to higher or lower hydration).

Hope this makes things a little clearer.

Keep on bakin'


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