I'm working on a chili recipe. It has a bunch of spices. I'm trying to figure out when best to add them. People sometimes recommend "opening up" spices like cumin by toasting them or frying them in hot oil along with the onions. OTOH, I have felt like cinnamon has much more punch-per-gram when I add it at the very end and don't cook it much/at all. I'm sure there's a lot of chemistry involved, and different spices will behave differently when brought to different temperatures, but I haven't seen good info on it.
So, does anyone have any information on "max temperatures" or cooking approaches with individual spices?
EDIT: I did just find this link, Indian Spices 101, which talks about it from an Indian culinary perspective. Interesting.