Image: Roasted coffee beans "Coffee Beans"byKonstantin Lazorkinis licensed underCC BY-NC 2.0
The entire Specialty Coffee movement is built around the production, processing and consumption of Arabica beans. Although Robusta can be found in many espresso blends but in terms of sheer variety of flavour and taste profiles, Arabica from regions around the world such as Brazil, Columbia, Kenya, Indonesia, India is far superior in the cup.
Robusta (Coffea Canephora), genetically is a parent of Arabica plant. Robusta tree is less sustainable to diseases and is easier to grow than Arabica and is cheaper than Arabica. It makes up for about 40% of global coffee trade. Robusta has twice the caffeine content of Arabica. Robusta is a staple of Italian espresso culture and important to the soluble coffee industry. When it comes to taste in the cup, Robusta generally has a woody and burnt rubber taste. It usually has very less acidity but a heavy body and mouthfeel. (Extract: The World Atlas Of Coffee 2nd Ed. - James Hoffman)