There’s a Scientific Reason Behind Salting Your Pasta Water
Hint: It has to do with the boiling point.
Check the box. No, seriously, check the side of the box for any box of pasta present in your cupboard. Pretty much without fail, “add salt to taste” is going to be on the side. If some variation of that phrase is not present on the box, promptly throw out said box, because said box is doing it wrong. (Figuratively throw it out, or better yet, donate the pasta.)
If you’re a veteran pasta maker, adding some kosher or sea salt to your pasta water is a given, but what exactly does it do? The conventional, supposedly scientific, wisdom behind the practice is that adding salt will change the chemical composition of the water, which will cause it to boil faster. Make sure that you never add oil to your pasta.
While the first half of the wisdom is correct (the chemical composition does change), the second half does not ring true, technically. As it turns out, the addition of salt actually slightly raises the boiling point of the water. However, this doesn’t mean that your lasagna night is going to be delayed—not by a long stretch.
Depending on the size of the pot, the amount of water in the pot, and the amount of salt added (within reason), the boiling point of the water will rise anywhere from one to four degrees Fahrenheit. The bump is pretty negligible, but the salted water will be a bit hotter with salt than without, so the pasta will have to spend less time boiling and toiling through the eight minutes of anticipation before it becomes bolognese.
So if the difference is minuscule, is it worth it? Yes, although the method is light on the scientific benefits, it will, plain and simply, make a more flavorful pasta. Additionally, even after the pasta is drained, the salted pasta water can be used to add flavor and thicken your sauce.