Impact of Natural Fermentation on Physicochemical, Microbiological and Cup Quality Characteristics of Arabica and Robusta Coffee

Information related to physicochemical and microbial dynamics during coffee fermentation and effects of fermentation duration on coffee cup quality is lacking in India. Hence, the present study was taken up with an objective to understand the physicochemical and microbial dynamics during fermentation of arabica and robusta coffee. The pH of the fermenting mass decreased from 5.43 to 4.71 and from 5.54 to 4.05 in arabica and robusta respectively. An increase in the temperature of the fermenting mass was recorded in both arabica (24-29 A degrees C) and robusta coffee (25.3-25.8 A degrees C). Good cup characteristics were obtained after 20 and 96 h of fermentation for arabica and robusta respectively. Yeast has been found to be the dominant microflora of freshly pulped beans followed by bacteria, as the fermentation proceeded; both bacteria and yeast have been displaced by fungal colonization. Naturally fermented coffee is found to produce slightly higher cup quality compared to the coffee processed by enzyme; alkali wash and machine wash.