How much to reduce salt when using salted butter in place of unsalted butter
I normally don't keep unsalted butter on hand since I use it so seldom. So when a recipe calls for salt and unsalted butter among its ingredients would it be alright to use salted butter and reduce the amount of salt? And if so, by how much should the salt be reduced? In other words, how much salt is typically contained in a tablespoon, ounce or gram of salted butter?
I always go the opposite. I keep unsalted all the time and never by unsalted. You can always add salt but it's very difficult to take away.
unsalted butter doesn't keep long, and if I buy a pound I never manage to use it before it is bad. So I buy salted and try to adjust.
@KateGregory, I don't think I use a particularly large amount of (unsalted) butter, but I've never had it go bad on me. If you're stocking up, put the extra packages in the freezer, but the opened package should be perfectly fine in the fridge, and we even keep a stick out at room temperature for spreading purposes. It's just too hard to tell how much salt your butter is adding; plus, there are times when you don't want to add any salt at all.
All types of butter keep nearly forever in the freezer, and it does it no harm. Cut your butter into sizes used for baking etc, and store in a ziploc style bag in the freezer
Depending on brand, it is approximately 1 1/4 tsp per pound (US), or a little more than 1/4 tsp per stick (4 oz).
For most applications, yes it is fine to substitute and adjust; you can just adjust the "salt to taste" step of your recipe in many cases.
There are a very few uses (such as yeast raised dough) where you want to be more precise. I would not use salted butter for a yeast dough by preference, but if I had to, I would calculate the amount of salt to remove from the other ingredients based on this ratio:
1 1/4 tsp salt / 16 oz butter