Differences between Arabica and Robusta Coffee.

Although arabica and robusta coffee may appear similiar appearance there are a number of differences - physical, chemical and genetical - that significantly differentiate them. The following list points out a few basic differences. 

1. Growing Conditions: The arabica coffee shrub typically grows between 2.5-4.5 meters in height, requires a temperature between 15^o-24^oC and an annual rainfall of about 1200-2200 mm/yr. Whereas robusta grows slightly taller 4.5 -6.5m, requires a warmer temperatures of 18^o-36^oC and slightly more rainfall (2200-3000 mm/yr) than arabica. Arabica typically also yields less coffee per hectare than robusta - meaning higher costs in production. 

2. Bean Shape: Arabica coffee beans are have a slightly larger/elliptical shape than the smaller, more round robusta beans. Structural differences also exist between the beans, which may explain why both beans roast differently under identical conditions. 

Arabica	Robusta

 3. Caffeine and CGA content: - Both caffeine and CGA have been documented as potential insect deterrents and chemisterilants. Arabica generally has less caffeine and chlorogenic acid (CGA) than robusta.  

 4. Lipid and Sugar Content: Arabica contains almost 60% more lipids and almost twice the concentration of sugar than robusta. Increased levels of sugars in coffee play an important role as its decomposition during roasting increase the level of perceived acidity and dissolved solubles in coffee. 

5. Pollination: Arabica is self-pollinating plant, meaning the plant will have fewer mutations and fewer variations throughout its life cycle as compared to robusta.

6. Chromosomes: Arabica has double the number of chromosomes at 44 than robusta at 22. 

While not comprehensive these are some of the basic differences between the both coffee species.