martinvic - great link to a good article - in all hot Asian countries the spices are on the ground drying in the sun - the same sort of effect would be to take the raw spices and put them in a cool oven like has been mentioned - however the spices that are purchased and considered raw are dried already they are not green and raw if you know what i mean - i personally like the spices just ground - to keep what oils etc they have left after being sun dried before packing and shipping around the world.
I see spices drying on whole areas of concrete - turmeric, chili etc etc everyday when there is no rainy season.
Its a point for an individual as is having to use curry leaves etc a lot of chefs have jumped on the band wagon re roasting spices......
best, Rich