Why Unsalted Butter?
After years of occasionally buying the unsalted butter that certain recipes demand... and having the remainder sit around unused after that, I've begun to question exactly why do some chefs insist upon it? Most recipes that call for it also add more salt elsewhere or "to taste" later in the recipe so it really doesn't make much sense.
Can't you just use regular salted butter for everything and cut the additional salt by a smidgen.... if it really matters?
Salt was originally added to butter as a preservative. I suppose people just got used to the taste of salted butter. The truth is, unsalted butter is purer; more care must be taken in manufacturing to remove the milk solids (which are what spoils in the short term; butter, like any fat, will eventaully turn rancid, but that takes a long time). Unsalted butter is specified A) because the amount of salt you then add to your recipe will be a precise and known quantity, B) because it tastes better more buttery and B) it's less apt to be old and have off flavors.
Just for kicks, try a side-by-side comparison: melt a stick of salted butter in one pan and a stick of unsalted butter in another. Note the greater quantity of milk solids, foam and other crud in the salted butter.
I use unsalted butter exclusively, and salt my food as necessary.
re: GG Mora
Two comments that are completely NOT meant as negative criticism, just observation.
1) the comment about a precise amount of salt amuses me because recipes rarely call for very precise amounts. The difference between 1/8 tsp and 1/4 for salt is huge. As is the difference between 1 3/4 cups flour and 2 cups. Yet no recipe calls for 1 7/8 cups. (skipping the weight vs volume issue).
2) if you use 1/2 stick salted butter you get a significant amount less butterfat than if you use 1/2 stick unsalted butter. (and as per my first comment, it's doubtful the recipe developer tried the recipe with 3.75 Tbl unsalted butter anyway)
I used to only eat salted butter and couldn't stand the taste of the "bland" butter. I started buying more unsalted for baking and then used it as "regular butter" . Over the years, snobbishness had a role here I'm sure, I've come to prefer unsalted and salted now tastes funny to me. The difference is greatest when you get some of the Eurobutter now on the market, such as Plugra or Celles sur Belle. There is a very great diff btwn these and Land o Lakes and Challenge, etc.
Of course, thinking butter tastes delicious is not exactly a wonderful thing as the waist enlarges.
tightly wrap what you have left in foil and keep in freezer for next time.
and never mind the melting and comparing the amount of foam. for a real taste test, just bite into a small piece of high quality unsalted butter, then try a piece of salted.
I don't think the whole salted v. unsalted butter question is totally an issue of oversalting a dish. I believe that most professional cooks prefer unsalted butter as there is no salt to cover up impurities in the taste and so the unsalted has to be of the highest quality.