It feels counter-intuitive to add water to a sauce in order to thicken it, but this trick works! As any Italian home cook will tell you, just a little starchy cooking water gives the sauce extra body and an almost creamy mouthfeel. Have you ever tried this?
All we do is dip out about a half a cup of the cooking water just before draining the pasta. It will look cloudy and yellowish from the starch. Stir this into your simmering sauce a few tablespoons at a time. The sauce will thin out a little and then thicken as the starchy water is absorbed.
This is less dramatic than adding cornstarch to a sauce or soup, but it works to bring the sauce together and make it silky. It works best with non-dairy sauces like tomato sauce, or with sauce-less pasta dishes like spaghetti carbonara or aglio e olio (pasta tossed with garlic and olive oil).
Give this a try next time you make a pasta sauce!
Related: Simple Finishes: 8 Ways to Round Out Any Pasta Sauce
(Image: Flickr member FotoosVanRobin licensed under Creative Commons)
Elizabeth Apron fro...

We do this all the time, it works so well and thickens any sauce nicely.
Excellent tip, I'm ashamed to admit it, but I've used flour and water for this before... Please don't ban me.... :)
Hmmm. I did it once and had to throw away an entire bowl of pasta. The salt I had added to the cooking liquid made the final dish WAY too salty.
I do this all the time! My favorite summer pasta dish is large shell-shaped pasta, with frozen green peas added to the pasta cooking water when the shells are about half done. In the meantime, I add a ladle-ful of pasta water to a bowl, and put in a spoonful or so of ricotta cheese. Add some salt and some fresh chopped basil, mix it up, then drain the pasta and peas and add them to the bowl. So delicious!
You could also add diced red peppers if you wanted a little more color. YUM, now I'm getting hungry!
Yes, my pasta sauces improved considerably after I learned this tip somewhere along the line.
@ I Heart Eating - too true! must taste everything for seasoning! Now I always taste the water after I salt it, the pasta after it cooks, and the sauce the entire way through so I can make any necessary adjustments.
Always tasting everything throughout saves a lot of grief in the kitchen. I did learn that lesson the hard way though.
We do this everytime. Makes a big difference.
Yes, I am so glad I learned to do this. Once in a while I forget to scoop out some of the pasta water and drain the pasta. It gives me that Charlie Brown 'Good Grief' moment.
For a thicker sauce yet, temper a beaten egg with the pasta water and mix it back into the hot pasta.
@LH-C recipe can be found here: http://www.flickr.com/photos/fotoosvanrobin/2619521020/
Yes this really works, but before you throw away the rest of the pasta water, here's another tip: when you drain the pasta, don't throw this water away. Either plug the sink or drain it into another pot. Before washing your dishes, use this water to give them a quick rinse. The starch in the water de-greases your dishes, and makes cleanup easier. Hope this helps.