In the ingredient list my recipe calls for 10 lbs of tomatoes. I'm not sure if this means before or after they are cored and peeled. What is the best way to measure tomatoes for canning sauce?
Unless specified, I would assume before cored and peeled.
And in general for any ingredient, unless explicitly specified: Raw, as bought in the store, before cleaning and/or preparation.
It makes assembling a shopping list easier, it makes buying easier, it makes writing a recipe easier, and it makes cooking a recipe easier.