The Main differences between the two species are that Robusta grows at lower elevations of around 100 metres, has a higher yield per plant and is more resistant to disease. Robusta beans are known for their strong, dirty flavour and high levels of caffeine. These beans are not generally palatable as a stand-alone coffee. The rule of thumb is that they have twice the amount of caffeine as Arabica beans. Many exported Italian coffee blends use Robusta beans to increase shelf life. The Robusta bean being cheaper to produce and higher in caffeine is mostly used in instant coffee production, but is still often blended with Arabica beans to give that extra caffeine kick that European city cafes often demand. Most multi national coffee companies will also use Robusta as a filler coffee in the production of instant coffee. Vietnam currently grows the second largest supply of Robusta coffee for the world market. This increase in cheap Robusta coffee has sent shock waves throughout traditional markets lowering green coffee prices considerably. The Arabica species, which came out of Yemen centuries ago, grows at higher elevations of around 2000 metres and is the source of all the world’s best quality coffees. The Arabica bean is a slower maturing plant compared to the cheaper Robusta plant. 75 per cent of the world’s total coffee production is Arabica. Most cafés and local retail coffees will be blends of Arabica beans from different countries of origin. So, when you see on the supermarket shelf, a marketing pitch claiming 100% Arabica blend, you will surely find most of the other coffees beside that package are also 100% Arabica. When talking Arabica, often the best beans are grown at higher altitude and because of this preference for high mountainous terrain, costs in growing and harvesting are higher which in turn makes some origins very expensive. high altitude, but relatively flat.