Pasta, water and salt

[james]

This relates to baked pasta dishes (which work great in a wood-fired oven) -- I know you are supposed to bring your water to a boil before you add the salt (and then the pasta). My question is why? Does it have to do with salt lowering the water temperature and slowing down the boiling process?

James

[DrakeRemoray]

Supposedly undissolved salt can pit stainless steel, so if you add salt after it comes to a boil it dissolved right away...

[maver]

OK, you're sending back to chemistry 101. You are right, salt dissolving in water is an endothermic reaction - it lowers water temperature. For the purposes of salt in a large pot of water I think this effect is insignificant. Salted water also has a slightly higher boiling point. Again, I think this is insignificant. When you add salt to boiling water the crystals of salt form a nidus for water vapor bubbles to form - this is why the water appears to boil more rapidly when you add salt - this is modestly cool to see (but not really much to talk about compared to plasma in the dome of the oven) and this rapid bubbling may be responsible for the short calming of the boil after adding the salt. The best reason to add the salt after the water starts to boil? I suspect tradition.

Marc

[BrianShaw]

I salt the water when it is cold - for both pasta and potatoes. Maybe that's why my SS spagetti pot has little rust spots on the bottom???

[oventhusiast]

Drake's right. It'll stain then pit the pot if you add it to cold water.
Rick

[vincent]

no chemistry here..as grandma always said..a little salt to help keep the water from boiling over and a little oil to keep it from sticking