The quality of Robusta coffee is increased by treating raw Robusta coffee beans whose water content has been increased to about 30% to 45% with steam at about 135.degree. C. to 140.degree. C. and at a pressure ranging from 3 bar to 4 bar approx. for 60 min to 120 min. This treatment particularly removes the substance responsible for the "earthy" and "musty" aroma note of Robusta coffee, namely the compound 2-methylisoborneol. After the treatment, the beans are processed and roasted in the customary way.