Quinoa should be stored unrinsed. Rinse it just before cooking to remove saponins, which can give it a bitter taste.
Quinoa has a natural coating called saponin, which can make it taste bitter. Rinsing quinoa before cooking removes this coating. However, storing rinsed quinoa is not recommended because the moisture can promote mold growth and spoilage. Instead, store dry, unrinsed quinoa in an airtight container in a cool, dark, and dry place. When you're ready to cook it, rinse the amount you need under cold water using a fine-mesh sieve until the water runs clear. This ensures you're removing the saponins right before cooking, preserving the quinoa's quality and preventing spoilage during storage.
To ensure all the saponins are removed, rinse the quinoa for at least 30 seconds, agitating it in the sieve. You can also soak the quinoa in water for 15-20 minutes before rinsing for an even more thorough removal of the bitter coating.