The first step to knowing your coffee is knowing what type of beans you are drinking. On the most basic level, beans are either Robustas or Arabicas. Robustas, traditionally associated with the lowest-end coffees, are slyly making their way back into the roaster — often masked as a sparky espresso or blended in with an Arabica to reduce a roaster’s cost (we wish we could say it ain’t so!). So, fellow coffee aficionados, here are your bean basics. Note: the QB / Mills only uses high-grown, shade-grown Arabicas.
Robusta, typically grown at low altitudes, is sun-grown and encourages the devastating practice of mono-cropping (growing the crop in the same field year-after-year — in this case, a field created by clear-cutting low-lying forests.). Aside from lower production costs, sun-grown plants are often capable of producing two crops per annum (versus Arabica’s single crop) and their coffee cherries, which are much higher in caffeine then Arabicas, are highly resistant to pests. Robustas often produce a mealy “oatmeal-like” taste with a lingering, bitter aftertaste.
Arabica beans, in sharp contrast to Robustas, are fragile and highly susceptible to environmental damage. They require shade trees to protect them from direct sunlight sun and nutrient-rich, moist soil to keep them hydrated. Because of their fragility, Arabica beans are vulnerable to attack from pests and are easily damaged by cold temperatures and poor handling. These beans, which typically grow 2,000-5,000 feet above sea level, must be harvested in the heart of the forest and transported back down the mountainside — often by hand. The risk of damage is high and the cost higher as the Arabica can only produce one crop per year. Arabicas, which characterize all of the world’s top coffees, produce a broad taste palate ranging from sweet-soft to sharp-tangy with notes and shades of earth, cocoa, orange, roasted nut.

Bottom line: Always look for Arabica! Shade-grown Arabicas not only produce a remarkable taste but they are also better for the environment.
For additional information, check out this article from the Atlantic