# How to calculate baker's percentages for indirect doughs?

I maintain a sourdough starter at 100% hydration (in other words, it contains equal masses of flour and water). Today I was documenting a recipe for pizza dough that includes some starter, and I wanted to include the baker's percentages. As I was doing so it occurred to me to wonder,

What constitutes the flour? In other words, what mass should I use as the denominator when calculating all of my percentages? Should I use only the total mass of all of the (dry) flours, or should I also account for the flour contained in the starter?

As an example, if a recipe's ingredients called for 500 g of all-purpose flour and 100 g of starter, should I consider the total mass of flour to be 500 g or 500 g plus one half of 100 g, which is to say 550 g?

I checked several cookbooks, including the 2nd edition of Jeffrey Hamelman's Bread: A Baker's Book of Techniques and Recipes. Nowhere did I find this question addressed specifically, but I did observe a pretty consistent trend: the authors (including Hamelman) did not include the flour contained by the starter when calculating baker's percentages.

To be doubly sure, I phoned King Arthur Baking's ever-helpful Baker's Hotline. The answer their representative gave me is that one is free to take either approach. I pointed out that this freedom must easily lead to ambiguity when bakers are communicating, to which he replied that when that is a concern, he'd suggest explicitly stating which approach one was using. He also confirmed my recently formed sense that of the two approaches, perhaps the more typical is the one that Hamelman uses in Bread: ignore the starter's flour in your calculations.

Afterward I found a discussion of precisely my question within King Arthur's page about baker's percentages under its heading "Baker's Percent and Preferments." In their terminology, when one performs the "slightly more complicated" calculation (counting the starter's flour as part of the total four), the result is the "overall baker's percent."

The rule I follow is that it's calculated by the flour that goes into the recipe as such. Anything contained in a preferment is not counted.

This aligns nicely with the purposes of using baker's percentages.

• it's a vehicle for easily remembering and executing recipes in a fast paced environment with complex social interactions. When you follow a recipe in a bakery (or tell your nervous apprentice to do so), you don't want to be calculating percentages in your head. Instead, you need a formula which tells you how much of each ingredient to grab - including how much of the preferment.
• it's a way for "standardizing" recipes. An experienced baker can make a very good guess at a dough's properties from looking at the formula. And here, the ratio of other stuff to dry flour is very predictive. Even the ratio of preferment to dry flour is informative! If you were to use total flour, you'd lose that purpose of the formula.