The effect of green bean particle size, temperature and roasting time on the quality and organoleptic characteristics of Toraja Robusta ground coffee

The quality of ground coffee is greatly influenced by the taste produced during roasting, especially due to the Maillard reaction that occurs in the coffee beans during the process. This study aimed to determine the effect of green bean particle size on variations in temperature and roasting time on the quality and organoleptic characteristics of ground Robusta coffee from the highlands of Tana Toraja regency. The research method used was the experimental method, with the treatment of green bean size (whole and 40 mesh chopped coffee bean), roasted using a roaster with furnace heating, with temperature variations (160, 180 and 200oC) and time (40, 50 and 60 mins). The measurement procedure followed the Indonesian National Standard (SNI) 01-3542-2004. The results of this study indicated that roasting 40 mesh size coffee beans at roasting temperatures increased from 160 to 200°C, with roasting time increased from 40 to 60 mins, resulted in lower coffee extract solids and higher ash content, thus not meeting the quality standards of SNI 01-3542-2004. Roasting whole coffee beans at 200°C for 50-60 mins produced better organoleptic characteristics (color, aroma, and taste) of ground coffee compared to roasting 40 mesh chopped coffee. The best treatment resulted from roasting whole coffee beans at 200°C for 50 mins, producing Robusta ground coffee with a medium dark color, a slightly strong coffee aroma and a very bitter taste; with a moisture content of 1.97%, an ash content of 3.28% and a coffee water extract content of 20.25%, meeting the SNI 01- 3542-2004.