Chemical characteristics of original robusta coffee beans from Jember fermented with Saccharomyces cerevisiae starter using the semi-carbonic maceration technique

This research aims to evaluate the chemical characteristics of original robusta coffee beans fermented using Saccharomyces cerevisiae . The method used is semi-carbonic maceration with variations in starter concentration (20%, 30%) and fermentation times (24 hours, 48 hours, 72 hours). The results of the research showed that samples with 30% concentration of starter and 72 hours fermentation times showed a decrease in chemical compound content with the lowest values, including caffeine content of 0.91%, reducing sugar content of 0.86%, and protein content of 10.79%. On the other hand, control samples without fermentation treatment had the highest values for each chemical compound content. The pH value obtained ranges from 4.97 to 4.47 and has a water content of between 10.20% - 11.37% and based on SNI. This research shows that fermentation with Saccharomyces cerevisiae can have an influence on the quality of original robusta coffee beans and is expected to provide good taste and aroma.