Arabica beans and robusta beans are two different species of coffee. They are the primary species of coffee that find their way into the American cup. The general differences are those of taste, and the conditions under which the two species differ in production.
Taste: Arabicas have a wider taste range, between varieties. They range in taste from sweet-soft to sharp-tangy. Their unroasted smell is sometimes likened to blueberries. Their roasted smell is perfumey with fruity notes and sugary tones.
Robustas taste range is neutral to harsh and they are often described as tasting grain-like, oatmeally. Their unroasted smell is often described as raw-peanutty. Their roasted smell is often likened to burnt rubber.
Production Conditions: Arabicas are delicate, they require cool tropical climates, lots of moisture, rich soil, shade, and sun. They are subject to attack from various pests and are extremely vulnerable to cold and bad handling.
Robustas are hardier plants, capable of growing well at low altitudes, less subject to problems related to pests and rough handling. They yield more pounds of finished goods per acre at a lower cost of production.
Economics: Customs and trade, supply and demand over the course of the last 150 years have determined the relative values of arabica vs. robusta beans. Generally speaking, the best coffees are all arabicas and the highest quality blends are pure Arabica blends. They are also the priciest.
In the U.S. you will generally find arabicas in the coffee store and specialty food shop, and robustas in the supermarket cans and jars of instant.
In Italy, home of espresso, the very highest quality brands are pure arabica, and like here, the popular-priced goods are blended with robusta beans. Because "Imported from Italy" can make an ordinary supermarket-quality Italian espresso a "gourmet" coffee in the U.S., you will find robustas in some Italian brands offered for sale in the United States.
The coffee you like is a very personal thing. You may find that you really prefer the all-arabica blends, or you may feel comfortable with something less, just because you like it. That's OK. The American marketplace, thanks to the Specialty Coffee movement here, is now rich enough in roast types, species, varieties, blends, brews, grinds, and price points to have something for every taste and pocketbook.
