Salted Water - how much salt is absored by the pasta ?
I've seen references to salt in water does not add sodium to your food (usually accompanied by a disclaimer - if you are on a sodium restricted diet, check with your doctor) (Huh!) Mine is a serious question. While I want to minimize the use of salt in my diet, I'd like to know (a) how much salt is absorbed when I cook pasta or vegetables in salted water - say 1 teaspoon to a large pot of water for pasta? (b) my second question - would I get less salt albeit also less tasty pasta if I salted it at the table?
I suppose you could do a (not very scientific) experiment if you wanted. Weigh the dry pasta before cooking and after draining and cooking. Assume that the difference in weight is due to absorbed water. Then assume (big and possibly incorrect assumption) that the absorbed water has the same sodium content as the water you cooked it in. Then divide by # of servings to determine the amount of added sodium/serving.
So if you add 20 grams of water to 1 Liter (1000mL) to cook the pasta in, the concentration of salt in the water is 0.020 gm/mL. Then if your 1 pound of dry pasta absorbs (total random guess) 100 mL of water it would have absorbed 2 gm of salt, divided by 4 servings, and you have an added 500 mg of sodium per serving.
I have no idea how much water a pound of pasta would absorb. Could be 50 mL, could be 200 mL. I also have no idea if the concentration of salt in the water absorbed by the pasta is identical to that in the bulk solution. But it's an easy place to start.
And I do think that boiling pasta in salted water produces a tastier pasta than salting at the table.
I think it's not so much the pasta absorbing the salt, although that happens to a small degree; rather the salt prevents the pasta from losing it's delicate flavor into the cooking water through osmosis:
Noun: The tendency of molecules of a solvent to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, equalizing the concentrations on each side of the membrane."
The pasta is the less concentrated flavor and the salt, when added to be as "salty as the sea", (just an expression) is the more concentrated solution. It is hard to say just how much salt is absorbed into the pasta; lots of variables. There is a small quantity of absorption of salt by the pasta; that's obvious, otherwise the pasta would be just a bland as it would be when cooked in unsalted water, and would have lost it's flavor through that osmosis thing. Since it's the only time you'll have to season the pasta (adding salt on top at the table just creates pasta with salt on the exterior, like a potato chip) To answer your second question, yes, the pasta won't be as tasty when adding salt to it at the table as it would be when salting the cooking water.
One teaspoon to a large pot of water, say 6 quarts will not flavor you pasta to any degree; 2000 milligrams a day, or one teaspoon, is the maximum recommended daily amount for a low sodium restricted diet. It is recommended to those following this diet to cook pasta/rice/cereals/grains without added salt.
There are other things you can do to flavor your pasta; add bay leaves, whole garlic cloves, an halved onion, peppercorns, a few splashes of an acid, vinegar or lemon or a cup of wine, low sodium broth, a few dried chile peppers if you like a little heat, herbs that you may use in your pasta sauce, although I would add them as fresh whole sprigs. Remember that you'll have to fish these flavorings out of your pasta; you can strain the pasta water after seasoning and before cooking the pasta, or tie everything up in a cheesecloth bag for simmering first; the latter would be easier by far.
I might add that pasta doesn't need to be cooked in a large quantity of water; that 6 quarts to a lb thing is just not necessary. This idea has been discussed here on CH; read these interesting articles on this subject:
I'm adding this info for cooking in less water, and enhancing the flavor of the water without salt would be more successful than trying to season 6 quarts of water.
It would be difficult to give you a specific answer, since it depends on a lot of different factors. Even if I had all the specifics, I doubt I would be able to give you a number. I've read/heard that pasta water should basically be as salty as sea water. That's pretty salty, and certainly more than one teaspoon for a large pot of water. Salting at the table probably won't absorb as well, though, again, I can't say how much is actually absorbing with any certainty. I'm feeling like none of this helps, but that's my understanding of the situation.
"I've read/heard that pasta water should basically be as salty as sea water."
Statements like this are crazy and should not be taken more than a grain of salt (pun intended). I am not criticizing you, just the person who originally made this statement, and now spread like wildfire.
Seawater is way too salty for even a healthy person. Just to give some perspective. Seawater is ~3.5% saline concentration. That is 35 gram of salts in one liter of water. 35 grams of table salt is about 2 tablespoon, and 1 liter is about 1 liquid quart.
So if you are making pasta in a 6 quart pot like this one:
Then you will likely use between 3-5 quarts of water. Let's say 4 quarts. This means you will need to add 8 tablespoons (1/2 cup) of table salt to make it similar to the saline level as seawater.
Chem, thanks for the technical info. Of course, if depends on what sea you're talking about...;-)
I have to say that I think that "salty as the sea" adage is an old Italian Nona's expression, probably been around for centuries, and is a bit romantic, if you will. I've heard some very experienced chefs right down to Rachael Ray use that expression, I guess they weren't thinking about the reality of salting that heavily. When you break it down, I doubt whether anyone ever used quite that much salt in their pasta water, to bring it up to sea water's level of salinity. I certainly don't, I probably use a few scant tablespoons to 4 quarts of water, but I don't measure it. That expression does cross my mind when salting pasta water, though.
I think it would be impossible to tell how much sodium is absorbed from the cooking water if it is salted, It would depend on the concentration of sodium, the type of pasta and how long it is in the water.
I think if you add salt to the top of the cooked pasta, you can get by with less salt than if it is cooked into the food. Of course if you are really restricted on your sodium intake, you probably wouldn't be adding any salt, cooking or otherwise.
I do think pasta tastes better cooked in salted water, probably because it has more salt!