I’ve come to understand that, in certain situations sour milk can be used.
I was getting ready to make scalloped potatoes, but the milk smells funky. I don’t see curdling though.
What’s the rule for sour milk? Would it be appropriate, in any case, to use it for my purpose?
If it smells bad, it’s not likely good for anything.
Can’t you use buttermilk?
when pasteurized milk goes sour, its just plain spoiled. Nothing to do with it but throw it in the trash and get some fresh milk for your scalloped potatoes “sour milk” for baking these days is usually milk to which a bit of acid, vinegar or lemon, is added to curdle it - it can be used as an alternative to buttermilk in baking recipes.
The question here is what sour milk is good for, not following a recipe that calls for it.
I’ve on rare occasions had pasteurized milk start fermenting in a not unpleasant, cheese-smelling way, though usually it’s just bad.