Whole spices release flavour slowly, which makes them ideal for tempering in hot oil at the start of cooking or for long, slow-simmered dishes where they have time to infuse.
Ground spices act faster and blend more evenly into a dish, which is why most masalas and marinades call for powders.
As a general rule, reach for whole spices when a dish will cook for a while and for ground spices when you need quick, even flavour, such as in a dry rub or a quick stir-fry.
