title_body: How can I determine the origins of coffee beans in a blend?
upvoted_answer: The short answer is no.  Short of genetic testing, it is near impossible to determine the origin of beans.  
  
  You may be able to make an educated guess at the whether or not Robusta beans are in the blend based the shapes of the beans and caffeine content.  But that would require a trained eye as as there is a great amount of variation in beans and it might be possible to mix up robusta, natural peaberrys, etc.  Robusta will raise the caffeine content, but depending on the blended amount, it may be hard to detect.