Since it is starch in hot water in both cases, I wonder why starchy pasta water is so prized over adding (trigger warning for Italians) warm water and cornstarch when tossing pasta.

  • Why are you adding cornstarch to your pasta water?
    – Catija
    Jun 18, 2016 at 23:08
  • 1
    When you make pasta, you HAVE pasta water. Adding cornstarch to water is an extra ingredient and step that is odd in the extreme given there's pasta water right there...
    – Ecnerwal
    Jun 19, 2016 at 0:51
  • @ecnerwal I cook in 4 - 3 quarts of water so there is barely any starch in the water.
    – Bar Akiva
    Jun 19, 2016 at 6:41
  • Others might prepare the sauce well in advance, and forget keeping any pasta water. Feb 2, 2017 at 17:07

3 Answers 3


Flavor, that is all. The water left over from boiled pasta tends to have the flavor of the pasta, and a salty flavor. If you season your pasta water with salt, and I always do, why not bring some of that flavor into the sauce you are preparing? Better than just tossing it all down the drain.

Does it really matter? No, not really. But, if you want to use some of that water for something, add your starch to it.


I think for a few reasons -

  1. it's being used to add a bit of "silkiness" and just a bit of body, but not a lot of thickening, so the pasta water has about the right consistency for that,
  2. as others have pointed out, the flavor, and
  3. Since #1 and #2 are taken care of, and you already are always going to have pasta water when making the pasta, the convenience of having it already there, with no additional or separate preparation needed.

I don't think there's anything particularly magical if you have the desire for adding cornstarch, there's just no particular reason for it, all things being equal.

  • 1
    I'd expect cornstarch to give the wrong texture. In pie fillings it has that glisteny, slippery texture. Maybe that's due to the sugar content, but I get a similar feeling from Chinese foods thickened with cornstarch. Feb 3, 2017 at 15:08
  • 1
    @JoshuaEngel - Of course, the texture would be different. Different methods will yield different results. I mention the texture in my answer (point #1). I would also never use cornstarch to thicken, say, gravy. But people do. If the user is fine with it, it will be different, but the flavors probably won't be ruined based on one type of starch vs the other. I do like the emphasis that your comment adds to the answer, though. I'd certainly never use cornstarch, but I'm trying to be non-judgmental. :D Feb 3, 2017 at 16:34

The starch in the pasta water has cooked for some minutes which reduces its taste. If you add raw starch to the sauce at the same time as the pasta the dish will get a starchy taste.

You could add the starch to the sauce several minutes before the pasta and cook the taste off if the sauce can handle it.

You could add some starch to the pasta water to make it work. Or you cook some starch-water seperately.

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