Baker’s percentages

Serious bakers list ingredients by weight, because scooping technique and humidity make volume-based measurement unreliable. Expressing weights as percentages of the flour weight makes it even easier to scale recipes up and down. This is completely different from normal math, where we’d use percentages of the total weight.

There are two approaches to percentage-based sourdough baking: one breaks the starter into flour and water weights, and the other treats it as a separate ingredient (ignoring the flour content).

As an example, consider a mix of 100g flour, 100g water, 10g salt, and 10g starter (itself an even mix of flour and water, aka 100% hydration). Using the first approach, we’d calculate percentages like this:

Using the second approach, we’d have this:

The Tartine bread book uses the second approach. Chad Robertson says that it’s more common in commercial bakeries: because the same starter is used in all the recipes, it’s easier to treat it as an ingredient rather than a mix of flour and water. I do the same.