Arabica and Robusta are the two major coffees around the world (as you can read in the my blog Genealogy of Coffee) but why are the different or similar? There are five major differences, First we will look at the growing conditions.

1. Growing conditions

The Arabica bean is a high altitude coffee and require the refreshing subtropical climates, lots of precipitation 47.25 to 86.5 inches (1200mm - 2200mm) a year, rich soil, shade and sun along with temperatures of 60 - 75 Fahrenheit (15 - 24 Celsius). Arabica coffee is subject to various pests, and are extremely vulnerable to low temperature and bad handling. Arabica's also must be grown at a higher elevation of 1950ft - 7200ft ( 600 to 2000 meters). The trees flower after rain and the cherries ripen in the fall after nine months. The root system is deep.

The Robusta is a hardier plant, capable of growing well at low altitudes of 650ft - 2600ft (200 to 800 meters), they require precipitation 86.5in - 118in (2200 - 3000mm) a year, they are capable of growing in harsher conditions then the Arabica. The optimal temperatures for Robusta are 64 - 96 Fahrenheit ( 18-36 Celsius). They are also less likely to have problems related to pests and rough handling. They also yield more pounds of finished goods per acre at a lower cost of production. The trees flower irregularly and take ten to eleven months to ripen. the root system is shallow.

2. Bean Size

Arabica Coffee has a larger bean that is elliptical is shape.

Robusta Coffee has a smaller round shape.

3. Pollination

Arabica is a self Pollinating plant making it that it will have fewer mutations and fewer variations.

Robusta needs to be pollinated and do to this there can be many variations or mutations.

4. Chromosomes

Arabica has 44

Robusta has 22

5. Caffeine

Arabica has much as 1.5% caffeine

Robusta has up to 2.5% caffeine , do to this probably makes it more of a deterrent for pests.