Ragi should be roasted *before* it is powdered. Roasting enhances the flavor and makes it easier to grind.
Roasting ragi before powdering is a crucial step for several reasons. First, roasting brings out the nutty and earthy flavor of the ragi, making the resulting powder more palatable and aromatic. Second, the heat from roasting reduces the moisture content in the ragi grains. This lower moisture content makes the ragi grains more brittle and easier to grind into a fine, consistent powder. If you were to powder the ragi first, the grinding process would be more difficult due to the higher moisture content, potentially resulting in a coarser, less uniform powder. Furthermore, roasting after powdering could lead to uneven heating and scorching of the powder, negatively impacting its flavor and nutritional value. Therefore, always roast the ragi grains whole before grinding them into a powder.
Roast the ragi on low to medium heat, stirring frequently, until you get a pleasant aroma and the color slightly darkens. Avoid high heat, as this can burn the ragi and impart a bitter taste to the powder.