What are the two most common coffees sold in the world?

As a very general and basic outline, we could say that the two most common coffees are the Arabica and the Robusta. Arabica is higher quality cofee grown in the montains. Robusta is more common, cheaper and easier to grow in plain ground. 

What is the difference between Arabica and Robusta coffee beans?

Types of coffee beans: 

75% of the coffee beans are Arabica in the world and 25% are robusta.

The comparison of Arabica coffee beans versus Robusta coffee beans: 

The main differences would be as follows: 

•  The Arabica coffee beans are large and the Robusta coffee beans are small. 

•  The Arabica coffee beans are extended in shape and the Robusta coffee beans are round. 

•  The Arabica coffee beans have curved creases and the Robusta coffee straight creases. 

•  The Arabica is acidic in taste and the Robusta coffee has bitter taste. 

•  The taste of the Robusta coffee is not as refined as the Arabica. 

•  Robusta coffee gives more cream than the Arabica coffee, hence better for the instant coffees. 

•  Robusta coffee has more caffeine compared to the Arabica coffee: 2.7% caffeine compared to 1.5%. 

•  The Arabica plant grows between 2.5 to 4.5 m compared to the Robusta plant which can reach a height of 4.5 to 6 m. 

•  Arabica coffee beans give off more of a sweet smell similar to blueberries before roasting whilst Robusta beans smell more nutty before roasting. 

•  Robusta coffee beans are grown primarily in the African continent and Indonesia while Arabica coffee beans grow in the African continent, Papua New Guinea and especially in South America. 

•  Of the two types, Robusta is more common given that it is a cheaper coffee. 

•  Arabica is higher priced- often double the price of Robusta.