The shot of espresso made of Robusta has more caffeine compared to Arabica. Robusta coffee beans have 83% more caffeine than Arabica. So, a cup of coffee made from these beans will contain 83% caffeine. Based on CoffeeChemistry.com, the Robusta bean has 2.2% of caffeine. On the other hand, the Arabica bean comes with 1.2% caffeine. The caffeine content of Robusta can be affected by several factors, including the quality of beans, growing conditions, and brewing method.