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“Salt it like the sea” is the most repeated line in pasta cooking, and it is wrong. Seawater is about 3.5 percent salt. Nobody cooks pasta in water that salty, and if they did, they would throw it out. We wanted a real number, so we measured.
The test
Four pots, each with 4 litres (about 4 quarts) of water and 400 g (14 oz) of the same dried spaghetti, cooked for the time on the packet. The only change was the salt, weighed on a scale. We tasted the pasta plain, then tossed with the same tomato sauce, which was itself lightly seasoned.
| Salt per litre | Concentration | Plain pasta | With sauce |
|---|---|---|---|
| 5 g | 0.5% | Flat, tastes of flour | Needed salt at the table |
| 10 g | 1% | Seasoned, mild | Balanced |
| 15 g | 1.5% | Clearly seasoned | Balanced, slightly forward |
| 20 g | 2% | Salty | Too salty once the sauce reduced |
Every taster picked the 1 to 1.5 percent range. That is 10 to 15 g of salt per litre, roughly a third to half as salty as the sea.
Why it matters at all
Dried pasta absorbs water as it cooks, roughly doubling in weight, and it absorbs the salt in that water evenly through the noodle. Salting the sauce later only seasons the surface. That is why unsalted pasta tastes bland even under a well-seasoned sauce.
The pasta water also ends up in your sauce. Most good pasta sauces finish with a ladle of cooking water to loosen them and help the fat emulsify. At 2 percent, that ladle pushes a normal sauce over the edge, especially a reduced one or one with salty cheese. This was the real problem in our 2 percent pot.
Measuring without a scale
Salt crystal sizes vary so much that a spoon of one brand weighs nearly twice what a spoon of another does. Here is what 10 g looks like in common salts:
- Fine table salt: about 1¾ teaspoons
- Morton kosher salt: about 2 teaspoons
- Diamond Crystal kosher salt: about 3½ teaspoons
- Flaky sea salt: don’t; it is expensive and dissolves the same as anything else
For a typical 4 litre pot at 1.25 percent, that is 50 g of salt, or about 3½ tablespoons of Morton kosher salt. Weigh it once, pour it into the measuring spoon you actually use, and remember where it came to.
When to use less
Drop to around 0.75 percent when the sauce is already salty: puttanesca with olives and capers, anything with anchovies, or carbonara with a lot of pecorino. Stay at 1.5 percent for simple sauces like garlic and oil, brown butter, or a fresh tomato sauce, where the pasta needs to carry more of the seasoning.
The short version
- Use 10 to 15 g of salt per litre of water.
- Measure once by weight and learn what it looks like in your spoon.
- Go lower when the sauce has salty ingredients.
- Always taste the sauce after adding pasta water, not before.