Oil temperature for flavor extraction? A little context:
I make craft chili oils for friends and family. I use a two-step infusion process. First, I infuse the oil for flavor with spices. Second, I add dried chili flakes into the flavored oil. I have used canola and grapeseed oil.

Questions: 


Is there an ideal temperature to best extract flavors/fragrances from spices (for example from cumin seeds or star anise) into the oil?
Do the flavor compounds deteriorate with prolonged cook times even if oil temp is kept below the smoke point? For example, how does the oil change when kept at 250 degrees Fahrenheit for 1 hour vs. 2 hours?
Depends on the oil, when we infuse like to think of it as steeping not boiling or heating to the point of just below the smoke point as the spices will cook and not infuse, some will also become bitter. I also suggest you put your chilis in all at once or toward the end of the infusion process if you are layering the flavor or want a less intense flavor. Also are your oils for dressings or for cooking? If they are for dressings they will keep their integrity when your process is finished, heating or cooking the oil will alter the taste you may be aiming for. Two different animals. Lastly I personally prefer grape seed or light olive oil for infusing.

Cheers!

EDG