I have a recipe I’ve found and like making because the crumb regularly turns out nicely for me, but I’d like it if the final loaf was a little bit bigger. If I wanted to scale up the recipe to make a 10% bigger loaf, would it be fine to just scale up each of the ingredients by 10% and bake it a little longer? Is there anything else I need to do? Any sort of formula for estimating changes to baking time?
You should be able to scale the ingredients linearly, but the cooking time increase will depend on the dimensions of the new loaf. If it’s just twice the mass in the same shape, you’ll want to increase cooking time by a factor of approximately the cube root of 2, adding about 25% of the original cooking time - but this is just an approximation for a guideline.
Also note that a larger amount of dough ferments faster. Not relevant when it’s a small increase but when doubled, quadrupled etc.
Yes, I scale bread formulas by percent like that. It does work. I never thought about a formula for the baking time, yes “a little longer” is pretty much my approach. So far so good.
I will say though - two loaves always comes out better than one for me. Always, and I have baked sourdough with this starter for 8 or 9 years now.