It increases the boiling point, due to boiling point elevation from adding a nonvolatile solute.
Nope, it stays right at the boiling point the entire time it’s boiling, with variations only due to convection currents and external cooling.
What TimeWinder posted is correct but incomplete, and I disagree that the temperature range would be so high under normal conditions.
If you graph the temperature with time while the burner is on, at first it rises linearly: added heat causes a proportional rise in temperature. When it reaches the boiling point, nothing obvious happens: the line flattens out, and it stays flat for a remarkably long time, as the water absorbs the heat of evaporation. When most of the water has absorbed this heat, boiling begins. This effect isn’t subtle and you don’t need any fancy gear to observe it: just use any cooking thermometer and glance at it every few minutes. You’ll see it reaches the boiling point and then takes several more minutes before the water boils (with a big enough pot of water, which is typically the case for making spaghetti.) If I remember correctly, it takes about half the time to reach the boiling point and half the time to absorb the heat of evaporation.
Why does it wait until most of the water has absorbed this heat? Because of convection currents, which tend to cause the whole pot to take on the average value. If it weren’t for convection currents, we could have hot pockets boiling while other pockets are cooler or at boiling point but with insufficient latent heat. We wouldn’t see any pockets over the boiling point.
I assume we’re heating from the bottom. When using a microwave, we can get less mixing because the heat isn’t necessarily well-distributed. If more heat is delivered to the top and cooling happens through the bottom, convection currents won’t be as effective.
Ever hear about “pinging” for making coffee manually? You don’t wait until the water is boiling; you wait until it’s pinging, which is when it’s beginning to boil at the bottom, but the bubbles of water vapor condense shortly after leaving the bottom. This is when the coffee turns out best. Using the water just as it reaches 212F makes the coffee too weak and doesn’t dissolve the heavier but desirable oils because the heat content is too low and the water cools off too quickly in the room-temperature grinds. Using it when it’s boiling hot causes too many of the even heavier, undesirable (bitter) oils to be dissolved because the water has more latent heat and stays hot too long.
Where does that latent heat go? Most of it goes into breaking the hydrogen bonds that form between (polar) water molecules. Nonpolar liquids have much lower heats of evaporization.
PS: this is all from memory from high school back in the early 70’s. I doubt the science has changed much, but my memory may be faulty. I’ll appreciate corrections from anyone who actually knows their chemistry.
A few times when making bread or biscuits, I’ve done the whole recipe right, except that I’ve left out the salt by accident. We’ve tried to salvage the result by putting something salty on them–salted butter, slices of ham, cheese, bacon, whatever. But it’s not very good. You need to have the salt baked into the bread or biscuits for the flavor to be right. When a biscuit is properly salted, you can still put a slice of country ham on it and have a tasty treat; the bread you use for your grilled cheese needs to have salt inside it as well.
Noodles are the same, IMO. If they’re not properly salted while cooking, it doesn’t matter how salty the sauce is.
Yeah, and Marcella Hazan, perhaps the Julia Child of Italian cookery in the English language, says in her seminal “Essentials of Classic Italian Cooking”: “For every pound of pasta, put in no less than 1 1/2 tablespoons of salt, more if the sauce is very mild and undersalted.” She recommends four quarts of water for one pound of pasta, which works out to roughly somewhere around 0.75%-1% salinity.
This may run things off on a tangent, depending on whether we think this thread is about salt, or noodles, or both. If just about the use of salt in the kitchen, then baking is a whole different chemistry. Salt usually interacts with other stuff (typically, baking powder and moisture of some kind) to create gassy bubbles that make baked goods airy. Then an egg-y substance helps the air pockets retain their shape. Weren’t those saltless biscuits kinda like eating doughy hockey pucks?
I made ice cream bread (from a recipe that was floating around on SDMB at the time) and gave-in when my wife objected to adding salt to the recipe. It ended up being a chocolate-mint flavored brick. :mad:
–G?
And now back to our regularly scheduled pasta…
