Design Development of a Food-Grade Huller Machine for Dried Robusta Coffee Cherries

Addressing the need for accessible and efficient post-harvest technologies in coffee production, this study develops a coffee hulling machine through a conceptual design inspired by existing hulling technologies and fabricated using locally available, food-grade materials. Conducted between August 2024 and January 2025, the evaluation explores the machine’s performance under four varying drum speeds, achieved by installing different driven pulleys on the rotating shaft: T1 (1001–1100 rpm), T2 (901–1000 rpm), T3 (801–900 rpm), and T4 (701–800 rpm). Each treatment undergoes three replications. The assessment focuses on output capacity, hulling recovery, hulling efficiency, and energy consumption rate, with data analyzed using a Completely Randomized Design and one-way ANOVA, followed by pairwise comparisons through the Least Significant Difference test at a 5% significance level. Findings reveal that higher drum speeds significantly enhance output capacity and hulling efficiency while reducing energy consumption per unit of output. The most favorable results—97.26% hulling efficiency, 92.66% recovery, and 42.22 kg/hr capacity—emerge at T1. At this optimal speed, the machine operates efficiently, consuming only 0.77 kWh. These outcomes underscore the machine’s potential viability as a practical and energy-efficient solution for local coffee farmers. Keywords: Coffee Huller, Robusta Variety, Design Development, Food Grade Application