If you are thinking of pouring the pasta water down the drain, you are going to be making a huge mistake. A culinary crime, some might say.
When you boil pasta in water, it turns to a cloudy-starchy liquid gold, and that is okay. Do not think that it is dirty, because it actually filled with leftover starch from the pasta and plenty of salt! It is a convenient byproduct that can boost the flavour of your dish when combined with the sauce, and gives the sauce a better texture. You know the silky saucy pasta you get when you order it in a restaurant, and tastes so delicious? That is because they use the leftover liquid instead of pouring it out.
First of all, it is not necessary to boil pasta in a large pot of water. The magic of the water is derived from the starch released during cooking, which can get diluted if there is too much water, making it useless in the end. Therefore, according to most chefs, it is best to use the amount of water that just about covers the pasta as it boils. Do not worry about the noodles sticking together, as long as you give it a stir throughout the first two minutes of cooking, it will appear just fine.
Once the pasta is cooked, the starch content will be concentrated in the water. Keep the liquid separately and cook the pasta with the sauce in a separate pan, adding a few tablespoon of the water into it as you go. This helps the sauce stick to the pasta, giving it a silky texture.
But what about the leftover water after it's been used? Save it for later! Keep it in the freezer, use it when making things such as soups, risotto, stews, or for adjusting the consistency of gravy. Think before you pour it out!
The next time you are making pasta, keep the remaining water to make your sauce smooth and super tasty. Who knows, maybe it will end up having a restaurant-quality taste?