title_body: How and when is flavoured coffee flavoured?
upvoted_answer: This site seems to suggest that the best time is just after the beans are roasted and still warm and "open", which makes some sense.  However, it does state that many flavorers cold flavor the beans and simply add more flavoring oils to make up for the reduced absorption.  I can't think of anyone that would flavor the beans before roasting.  Not only would the high heat of the roasting risk degrading the taste of the flavoring oils, it would also affect the roasting process and flavor the roasting equipment.
  
  As for distribution, I believe most of the flavoring agents are fairly potent and the process is a sprinkling or pouring then mixing, and not a soaking.