Differences in chemical characteristics due to different roasting of robusta coffee beans

Abstract

Roasting is a process that contributes to the formation of compounds and flavors in coffee beans. Temperature and length of time are the main factors in the roasting process. Generally, the range of temperatures and roasting times varies significantly for different varieties of coffee beans. This study aims to determine the effect of roasting on changes in the chemical characteristics of robusta coffee beans (Coffea canephora) from Sidomulyo Village. This study used different brewing methods to brew roasted robusta coffee beans with the best chemical characteristics used a factorial randomized block design with two factors: roasting temperature, which consisted of three levels (185, 190, and 195 ⁰C), and roasting time, which consisted of three levels (10, 13, and 16 minutes). The roasted coffee beans were analyzed for water content, ash content, caffeine content, total phenol, and pH. The results of this study obtained a water content value of 3.523 ± 0.129% to 1.939 ± 0.025%, ash content of 8.119 ± 0.115% to 4.315 ± 0.260%, a caffeine content of 2.494 ± 0.015% to 2.176 ± 0.021%; total phenol of 6.251 ± 0.101% to 4.334 ± 0.117%; and a pH value of 6.675±0.126 to 4.075±0.171. At this stage, the best treatment (Zeleny method) is produced by robusta coffee beans roasted at 185⁰C for 10 minutes. Robusta coffee beans with the best treatment have a moisture content of 3.523 ± 0.129%; ash content of 4.315 ± 0.260%, the caffeine content of 2.494±0.015%; total phenol of 6.251±0.101%; and a pH value of 4.075±0.171.