Growing up I recall we only had one choice for butter and that was salted. All my old cookbooks only state 'butter' to be used in recipes. Can I substitute unsalted and add more salt to the recipe?
Yes you can. The amount of additional salt to add would be miniscule.
That's often what I do! I'd say that most recipes now assume unsalted (and list a quantity of salt in the ingredient list). If it does list salt, you probably don't need to add more; if it doesn't, add to taste. (I just add a fat pinch.)
And using unsalted butter gives you more control over the total salt content as well as flavor of whatever you are making.
I always use sweet butter, no matter what the recipe specifies. Look for a sweet, cultured butter, which has an excellent flavor. Don't add more salt--it shouldn't make any difference in the recipe.
I wouldn't worry about it, the recipe was most likely over salted to begin with. It used to have a bit less moisture than salted, but I don't think that's true anymore. Up until 15-20 years ago it was mostly a specialty item, and was generally kept frozen. I don't know if they changed it or just found that refrigeration was adequate, but it's quite common now; it's pretty much the default baking butter now.
salt is usually used as a preservative in butter so i only buy unsalted. i store the excess in the freezer until ready to use. i don't use a lot of salt in my cooking and like to control the amount, especially if i use something like pickles or olives or some such ingredient in cooking which would make the salt in butter redundant. i find that when we buy it by mistake, even a buttered piece of bread is strangely too salty. and really, i'm not anti salt.
Absolutely. I would go with the unsalted and not add more salt right away if salt can be added later. I always test for salt before plating. Only time I use salted butter is to accompany bread.
For me, unsalted butter has been the norm for decades - even as a kid, baseline butter was unsalted. Nowadays, I sometimes get really good salted butter for bread, but beyond that I generally assume unsalted for cooking, as Caroline said.