I think measuring by mass is almost certainly more precise in theory, but in practice sometimes measuring by volume is easier to do, and therefore can be more a

I think measuring by mass is almost certainly more precise in theory, but in practice sometimes measuring by volume is easier to do, and therefore can be more accurate in practice sometimes. Most of the arguments about actual composition of ingredients (hydration of flour for example) and so forth can be extended to volume as well. Baking is also precise but it's not complex chemical synthesis. So I could flow with his attitude. What I've decided for myself is that the mass versus volume measurement really matters when the ingredient "measurable unit" size is very large compared to the amount needed for the recipe. So for something like granulated cane sugar in a muffin recipe, using mass versus volume probably won't matter very much, because the individual sugar crystals you are "counting" are very tiny compared to the amount you'd use in a recipe. There's probably going to be a bigger difference due to your impatience or the scale accuracy or whatnot than using volume versus mass. However, for something like whole walnuts, mass is going to be a lot more precise because there's potentially a lot of change between adding another 1 or 2 walnuts given the 1/3 cup you might need, they can shift around, etc. At least that's where I've come down on it for myself.