Robusta is a sturdy species of coffee bean with low acidity and high bitterness; it is used primarily in instant coffee, espresso, and as a filler in ground coffee blends. The bean comes from the Coffea robusta variety of the Coffea canephora plant (widely known itself by the synonym Coffea robusta) which has its origins in central and western sub-Saharan Africa. Robusta is easy to care for, has a greater crop yield, has almost double the amount of caffeine and more antioxidants, and is less susceptible to disease than arabica coffea. Roasted robusta beans produce a strong, full-bodied coffee with a distinctive, earthy flavour, but usually with more bitterness than arabica due to their high pyrazine content.
About 30% of the coffee produced in the world is robusta. It is mostly grown in Vietnam, where French colonists introduced it in the late 19th century, though it is also grown in India, Africa and Brazil, where it is often called conilon. In recent years, Vietnam, which produces mostly robusta, has become the world's largest exporter of robusta coffee, accounting for over 40% of the total production. It surpasses Brazil (25% of the world's production), Indonesia (15%), India (6%), and Uganda (4,5%). Brazil is still the biggest coffee producer in the world, producing one-third of the world's coffee, though 70% of that is C. arabica.
Robusta is easier to care for and has a greater crop yield than C. arabica, so is cheaper to produce. Roasted robusta beans produce a strong, full-bodied coffee with a distinctive, earthy flavour, but usually with more bitterness than arabica due to their pyrazine content. Since arabica beans are believed to have a smoother taste with more acidity and a richer flavour, they are often considered superior, while the culture and processing of robusta has for a long time been neglected and focused on unwashed beans, resulting in a harsher taste. However, the powerful flavour can be desirable in a blend to give it perceived "strength" and "finish", noticeably in Italian coffee culture, and carefully processed, washed robustas can be superior in quality and provide a milder taste than some lower quality arabicas. Good-quality robusta beans are used in traditional Italian espresso blends, at about 10-15%, to provide a full-bodied taste and a better foam head (known as crema). Robusta is also used as a stimulant, diuretic, antioxidant, and antipyretic, and relieves spasmodic asthma.