Green Lentils 100g Bring your liquid up to a boil, add your lentils, then turn down your heat to a simmer for at least 25-30 minutes. Keep tasting your lentils as they cook to see if they're the consistency you want, more firm if you're eating them on their own or in a salad, and softer if they're going into a soup or stew Storage instructions Keep in a cool and dry place out of direct sunlight.