Calculating Final Dough Hydration from Baker's Percentages
When baking with any type of starter/levain/biga, it seems pretty important to know the final dough hydration of a recipe, as that is a much better way to gauge the feel of the dough than just the base hydration. (especially when a large amount of starter is used)
Of course, if the hydration of the starter matches the hydration of the dough recipe, there's no need to calculate. But usually this is not the case...
I did some math and came up with the following formula that you can use to caluculate the final dough hydration, just based on the Baker's Percentage numbers (i.e. without taking any weights into account).
fdh = final dough hydration
h = hydration (the ratio of water to total flour in the recipe)
sh = starter hydration (the ratio of water to flour in the starter)
sp = starter percentage (the ratio of starter to flour in the recipe)
If you know the amount of starter you want to use, its hydration, and the final dough hydration you want, you can solve for the hydration (ratio of water to flour) you need in the recipe:
I'm surprised that the formulae are so complicated, but I guess that's math for you. I really wish all recipes would list the final dough hydration along with the other numbers, as it's annoying to have to calculate it yourself!
I'd appreciate any comments as to whether this is useful or not, and checking of my math. Thanks!