Coffee beans can either be Arabica and Robusta. Arabica grows at high altitudes with mineral-rich soil and needs more care and milder temperatures than the Robusta plant. Robusta, however, prefers warmer climates. Robusta beans tend to contain more caffeine, produce a rigid plant, and a bitter, more rubbery tasting coffee. Arabica is considered the more superior tasting bean, tasting smooth and almost sweet, with flavor notes of sugar and chocolate. The Arabica bean is oval-shaped and longer, while Robusta is smaller and round. The seeds are dried and hulled, polished, and then shipped out as 'green beans' that still have a layer of cells tightly attached to the bean until roasting.