Pasta that is being served warm should never be rinsed after cooking. The starch on the outside of the pasta strands mixes with the sauce and helps the sauce stick to the noodles. Water for cooking pasta should be adequately salted. Salty like the sea is the common expression. In addition to flavor, salt actually helps rough up the exterior of dry pasta while cooking which also helps sauce adhere. Oil should not be added to cooking water for pasta because it will also make sauce slip off the pasta strands. An exception to the don’t rinse rule is when you are making a cold pasta dish. It is then recommended that you rinse pasta so it doesn’t stick together. After rinsing, you can toss with a little olive oil to prevent clumping. When cooking pasta, save some of the cooking water. It can be used to build the sauce and help it coat. It can be used to thin a heavy sauce that is not distributing well. *Here is unrinsed, warm pasta added to a warm bowl. *Adding some butter, pasta water and cheese makes a sauce that coats all the noodles well.