The classical framework of shad rasa divides flavor into six tastes: sweet, sour, salty, pungent, bitter, and astringent. In Ayurvedic thought, a satisfying meal includes all six, and each taste is associated with particular effects on appetite and digestion.
In practice, the framework works as a balancing tool. A dal that tastes flat may need sourness from tomato or lemon; a bitter green is softened with jaggery; a rich curry is cut with a spoon of yogurt. Cooks who learn to name what a dish is missing in these terms can correct it without a recipe.