I have often wondered why some recipies call for salt
to be added to boiling water.
Does the salt cause a “rolling boil?” Does it keep pasta from sticking to the pan?
What is its purpose???
And, is it “optional” sometimes for health reasons?
I don’t feel like I can list “cooking” under Hobbies & Interests until I know this answer.
Thanks!
Isabella
One effect of adding salt to water would be to increase the boiling point of the solution thus probably cooking the pasta better and it tastes better with salt. The same effect , in the opposite direction, is the reason that salt is spread on roads in cold weather. In this case the freezing point of the wet road is lowered by a few degrees and thus it takes longer for the ice to form.
I’ve always wondered too. Godd question.
But I did hear that you should never add salt to the water when you are boiling fresh corn.
Adding salt (a solid) into a semi-solution with the water ( a liquid) raises the boiling point of the water (only slightly of course), allowing the pasta to cook at higher temperature.
The higher temperature makes the pasta attain a firm “skin” which keeps it from turning to a mush and gives it a “tighter” texture (my own description). The reason for this is because you don’t have to cook the pasta as long to reach the desired level of doneness.
The salt is also reacting with the pasta physically, helping to achieve the same desired “skin”. If you have ever made bagels, you will have already seen what the effects of boiling a dough, which is what pasta essentially is.
Please, for the sake of your pasta, always salt the water. If you are concerned with your sodium intake, leave a little salt out of whatever sauce you will be using or substitute another spice for the salt.
The amount of sodium that is on the pasta boiled in salt water is actually not very high–it does season the pasta, and if you really are very concerned about your sodium intake, use a low-sodium sauce. The salt in the water also helps give the pasta the al dente texture that is usually desired.
About vegetables, I learned to blanch vegetables in salt water (“it should taste like the ocean,” said my chef instructor), because it does raise the temperature of the boiling point, and will cook the vegetables quicker, along with instantly seasoning them.
I have found that Kosher salt works well for boiling purposes, because it tastes saltier, hence you will use less (and it also has a lower sodium content per teaspoon than your regular table salt, if that is a concern).
Someone on the boards here did the math once, and figured out that for typical recipe measurements, the temperature is raised only by a tiny fraction of a degree, far too small to make any difference in cooking times. So it seems that flavoring, and any chemistry that may go on, are the real reasons for it.
Naw, the real reason is that people think that it’ll make a difference. Salt in the cooking water doesn’t have any more effect than rinsing the noodles in cold water before serving.
If you want your pasta al dente, then you just don’t cook it for quite as long. Salt doesn’t have anything to do with that, either.
Yep, the tiney pinch of salt added to the water is practically insignificant for raising the boiling point of the water… your elevation above sea-level would have a greater effect. And unless you’re stiing there with a stopwatch and thermometer and several replicates, you’re not going to notice the difference anyways. You know when something’s done cooking by observation and experience, not by consulting a table of chemical properties. Taking the lid off a pot of water a few seconds too soon or late would totally throw off the cooking time anyway, as would not starting the water boiling from the exact same temperature every time too.
It gives a slight difference in taste (if you’re that observant to start with) and gives one a sense that they’re doing something more complex and refined than dumping in some dry noodles and applying heat to water.
As Smeghead says, the effect of a few pinches of salt on the boiling point of water is tiny.
A few grams of salt will however, have a large effect on the ionic strength of tap water. This in term will affect the rate of diffusion of the water into food during cooking (mojo filter’s “skin” formation on pasta), as well as the rate at which natural flavorings and salts diffuse out of the foods.
Many biological polymers (e.g. food) are extremely sensitive to changes in the concentration of ions within the 0-150 mM range. As the salt concentration changes, the molecules change shape, become more or less soluble, complexing with more or fewer water etc. The taste and texture of food is affected by the conformation and hydration states its’ component molecules.
Rinsing in cold water stops the cooking process. If you don’t do that, the pasta will be cooked further. Salt is supposed to prevent the pasta from sticking. I don’t use it and I don’t notice any difference.
I thought oil is used to prevent the pasta from sticking. I never heard that salt was supposed to do that.
What’s up widdat? Someone told me once it makes the eggs easier to peel. True?
Thanks
Quasi
No wonder I never noticed any difference.
So, let’s say just for example, I’m cooking pasta in Denver.
Does this mean that no matter what, salt or no, my pasta isn’t going to be as good as if I had cooked it in Frisco?
FWIW, Manservant Hec, the pasta I cooked in Utah (higher elevation than Denver) is exactly the same (with salt) as when I cook it here in the Bay area (with salt).
IIRC, one of my chef instructors told us to do this–something to do with a chemical reaction that makes the shells come off easier. I never really noticed a difference. I do notice the difference when I plunge just-boiled eggs into ice water. Not only does it stop the cooking process (helping to eliminate that grey sulfur ring around the yolks), but it seems to help with making the shells easier to peel.
The Italian that I cooked with at school used to make the water very salty. She said that us Americans don’t use enough. Spoons of the stuff were used- it tasted less salty than the ocean, but you definitely knew there was salt there. I always thought that the salt had the altitude/temperature benefits (being a Denver cook), some osmosis benefits of getting the water into the core of the noodle faster, and some texture benefits. But, it could all be bunk.
For eggs and crab I add a spoon of vinegar to the water to help the eggs peel and the crab meat not to stick to the insides of the legs. Again, just doin’ what mom said, but it seems to work.
-Tcat
You can use the osmosis effect if your soup is too salty. Just put a raw potato into the liquid and leave it for a while and the potato will absorb the salt and make your soup more palatable.
Actually, my chemistry teacher told us that, to raise the Boiling Point (BP) of water you would have to add one mole of salt (a lot more than that light sprinkle). The formula for determining the change in boiling point is:
Delta T = i-factor X # moles X boiling constant.
From about any P-chem book the equation for boiling point elevation boils down to Delta T = K m, where m is the molal (moles/1000 g solvent) concentration of the solute and the constant K includes the hesat of vaporization of the solvent, the gas constant etc. K = 0.51 for water. Thus 1g/L salt (0.017 M, a good healthy dose) would raise the boiling point by 0.51 X 0.017 = 0.0085 degrees centigrade or 0.016 degrees Fahrenheit. Putting the lid on the pot probably causes a larger change !
But if you just want to increase the rate at which the starch molecules on the outside of your pasta expand during the cooking process, 20 to 100 mM salt can have a big effect.