How to salt pasta water
October 1, 2026
About 10 grams of salt per litre of water, which is 1 percent by weight. That is the only chance to season the pasta itself, and it changes the boiling point by an amount too small to matter.
The measurement
| Water | Salt at 1 percent | In spoons, roughly |
|---|---|---|
| 1 litre | 10 g | 2 teaspoons of fine salt |
| 2 litres | 20 g | 1 tablespoon and a bit |
| 4 litres | 40 g | 2 heaped tablespoons |
Weigh it once with scales and look at what that volume is in your own salt and your own spoon. Salts differ enormously by volume: coarse flaked salt takes up roughly twice the space of fine salt for the same weight, so a recipe in spoons is wrong for someone using the other kind.
What the salt is doing
Pasta absorbs water as it cooks, and it absorbs whatever is dissolved in that water. Salt added later sits on the outside of the finished pasta and in the sauce. Salt added to the cooking water is inside it.
You cannot fix unsalted pasta afterwards. You can only put seasoning next to it.
The boiling point claim
Salt raises the boiling point of water, and the amount is worth calculating once so that it stops coming up.
Ten grams of salt is about 0.17 moles, and it splits into two ions in solution. Multiplying by water's boiling point elevation constant of 0.512 C per molal gives a rise of under 0.2 C.
Two tenths of a degree changes nothing about how the pasta cooks. Salting water to cook faster does not work; salting it to season the pasta does.
"Salty as the sea"
Sea water runs around 3.5 percent salt. Following that advice literally puts 35 grams into a litre, three and a half times the figure above, and produces pasta that has to be served with an unsalted sauce to be edible.
The phrase survives because it is memorable. Use the number instead.
When to add it
Add it once the water boils, or before. The pasta cannot tell the difference, since it goes in after either way.
There is one practical reason to wait for the boil: undissolved salt sitting on the bottom of a warm stainless pan for a long period can pit the surface. Salt dropped into already-boiling water dissolves in seconds and never settles.
Two things to leave out
Oil in the water does nothing useful. It floats, so it never reaches the pasta while it cooks, and the film it leaves on drained pasta makes sauce slide off. Pasta sticks because the pot is crowded or because it went in before the water boiled, and stirring for the first thirty seconds fixes both.
Rinsing after draining removes the surface starch. That starch is what makes a sauce cling, which is also why a ladle of the cooking water belongs in the sauce before the pasta does.
How much water
Enough that the pasta moves freely, which is about a litre for every 100 grams. Less water than that concentrates the starch, and some cooks use that deliberately for a thicker sauce.
Keep the ratio if you reduce the water: 1 percent of whatever you use. Halving the water and keeping the salt doubles the seasoning.
Sources
The boiling point elevation constant for water, 0.512 C per molal, from the CRC Handbook of Chemistry and Physics
Average sea water salinity of about 3.5 percent, from NOAA
How to make a pan sauce, for where the starchy cooking water earns its place