Why are you supposed to salt the water for boiling pasta? Doesn't this lower the boiling temperature and make you sauce seasoning off?
I don't have the answer to the first part of the question about lowering the boiling temperature. But I have found that if I don't salt the pasta well enough during the cooking, when the pasta gets topped with the sauce the sauce will taste "watery". The sauce will taste fine by itself but in combination with the undersalted pasta everything is kind of flat.
I add salt to the water immediately after I add the pasta. I agree with Verdigris as to the taste of both the pasta and sauce.
A generous amount of salt in the water seasons the pasta internally as it absorbs liquid and swells. Amanda says that the water should taste like sea water. Even with that, you're not adding enough salt to raise the temperature more than about 1°F.
According to author/food scientist Harold McGee, any physical/chemical effects are minimal. It all comes down to taste: pasta cooked in unsalted water is bland, and salting after the cooking doesn't help.
Carla, I grew up in a household that ate speghetti three times a week. We did not call it pasta and we are northern Italian. We did not salt our water or put oil in it. We cooked our pasta al dente and after draining it put it back into the same pot with the burner on and stirred until it started sticking and then added the sauce and then served with a little more sauce on top. Later in life I heard about salting the water as salty as the sea. But when I did I found that it was throwing the flavor of the sauce off. But to verdigris point, my mothers and grandmothers sauces were so wonderful that the pasta could never taste watery or bland. The pasta absorbed the sauce and that was the flavor. Now, when I was in Italy I did notice that the pasta was lightly salted and it did not throw the flavor of the sauce off. So, being that I grew up surfing and still do from time to time I beleive that "salty as the sea" maybe a bit misleading as I do know what sea water taste like. My experience is that salty as the sea doesn't mean that my strand of pasta should be "salty"after cooking.
But remember you will not get struck down by lightning if you do not follow this rule. Your a cook and if you like what it is that you are cooking then most likely so will someone else. Good luck!
P.S. SoCal Rules!
In the words of Marcela Hazan, pasta cooked in unsalted water tastes "insipid." In Italy pasta is sauced far less generously than it is here in the US. Italians want to taste the pasta itself and not just the condiment.
Although I do agree and respect my friend pierino and Marcela I have to say that cooking isn't always about following rules or doing what the Italians do or even what a recipe says. Cooking is like Jazz, there doesn't have to be sheet music. Do your solo, just make sure your playing in the right key.
Harold McGee has some provocative ideas about boiling in less water (much less!): http://www.nytimes.com....
Here is an interesting science experiment on boiling points http://www.miniscience.com/projects/saltwater/index.html
Not sure why boiling at a higher temperature should matter. As another commenter wrote for the most part it is about taste and also what you are going to do with the pasta with regard to sauce.
Don't find any trouble getting the water back to full boil after salting it.
The other comments above are all valid. Adding only, that it is my understanding that more salt is required to season pasta after boiling than the amount absorbed by salted cooking water.
Salting water or not, one would, of course, need to take it into consideration when balancing the seasoning of the sauce.
Add the salt after the water has come to a boil but before the pasta. That way you're not heating the salt and it has time to become incorporated in the water before you add the pasta. I've never "lost" a boil after adding salt.
I've been using the McGee method for over a year now. I put the pasta in just enough boiling, lightly salted water to cover & it turns out fine every time. This saves on heating large amounts of water and I don't have to handle a vast heavy pot when it's cooked.
Starting the pasta in cold water doesn't make much sense to me - it takes the same time and amount of fuel to bring it to a boil.
adding salt actually raises the boiling point, however the salt is to season the pasta. I never put olive oil as it will prevent the pasta from absorbing the sauce