Most quinoa brands come prerinsed. Check the bag and see it if it says rinsed anywhere on it. If the quinoa is already rinsed, there's no reason to rinse it again! It doesn't taste any different if you do and it's one extra step. The reason quinoa needs to be rinsed in the first place is due to a natural chemical called saponin. The seeds are covered in it and it tastes slightly bitter.