Physical properties of arabica green coffee beans grown at different farm elevations in Gayo higland, Indonesia

Abstract Gayo Arabica Coffee (GAC) is renowned for its unique aroma and flavor, particularly in Indonesia’s Bener Meriah and Aceh Tengah Districts, which are crucial for Arabica coffee production. This study evaluates the quality attributes of GAC from two post-harvest processing methods (semi-washed dry hull and honey) at three elevation levels (1100-1200 m, 1300-1400 m, and 1600-1700 m asl), totaling 18 experimental units. Key assessments included yield, physical characteristics (triage tests, defect point, bean size, and bulk density) of green beans. ANOVA and Tukey’s HSD test were applied at a 95% confidence level. Results showed that elevation and processing methods significantly influenced defective bean values (P<0.05), with both factors greatly impacting defect percentages (P<0.01). Elevation alone significantly affected green coffee bean density (P<0.01). Post-harvest methods influenced total caffeine content in roasted beans (P<0.05). Pearson correlation revealed a strong positive relationship between elevation and bulk density (r = 0.88) and size of beans (r = 0.62), while both elevated elevation and bulk density correlated inversely with defective beans (r = −0.75 and −0.58, respectively).