Robusta coffee is grown at lower altitudes. It grows slightly taller at 4.5-6.5 meters (8.2-21.3 ft.). It requires warmer temperatures between18°-36°C (64- 97°F) and slightly more rainfall (2200-3000 mm/yr.) than Arabica. It has low acidity and high bitterness.
Robusta beans are used primarily in instant coffee and espresso. Its taste is described as burnt tires or rubbery, which certainly does not sound good. It has more caffeine than Arabica. Research shows that the Robusta bean has 2.7% caffeine content; almost double the 1.5% of Arabica.
Robusta is easier to tend to on the farm, has a higher yield and is less sensitive to insects – the extra caffeine is a chemical defense for the coffee seed as the quantity in the Robusta is toxic to bugs.