Processing methods used in the commercial milling of quinoa usually remove most of the saponins found in the outer coat of the quinoa seeds. Because the quinoa saponins are largely responsible for its bitter taste, many people chose to rinse and rub the seeds after purchase to remove any bitter taste that may remain in the seeds. An effective method to do so is to place the quinoa seeds in a fine-meshed strainer and run cold water over the quinoa while gently rubbing the seeds together in your hands. After completing this process, you can taste a few seeds to determine if a bitter taste remains. If it does, simply continue this rinsing and rubbing process until you no longer taste a bitter residue.