Your uncle has a tea estate ? Yes; I've heard of many "non-coffee ingredients" in the decoction making. Roasted chicory is the top pick for many. Roasted fenugreek gives a distinct taste that people who eat dosa, idly sort of breakfast like it. Not as common as chicory. Indonesians add cloves (crushed and added as a whole piece) Adding a grain of kosher salt to coffee grinds is an old custom that came from bedouins, arabs, and people in the origin of coffee area - eritrians and ethiopians. This has to do with adding lost ions (just like runners do) due to the hot weather they live in. Adding milk/cream to coffee is very european. Sugar addition is also european. I thought you are buying coffee/chicory mix from indian grocery stores in USA; aren't you ? Coffee grounds should smell the way you like it, even before you spoon it into a coffee filter. When the smell is right, then the decoction will come out smelling the way you want.