Arabica and Robusta are different coffee tree species. Arabica beans create a more "smooth" cup of coffee and are considered by many as more desirable, while Robusta beans often have a stronger "coffee taste" and its beans usually contain more caffeine. The geographic location, altitude, and soil will give Arabica or Robusto beans different flavor profiles. Blends can be a combination of Arabica beans, mix of Robusta beans, or a blend of both species of coffee beans.