Physicochemical and Dimensional Characterization of Coffea liberica Beans from Nawangan, East Java, Indonesia: Effects of Roasting Profiles

Abstract

Liberica coffee (Coffea liberica) demonstrates adaptability to lowland climates, positioning it as a resilient candidate amid climate change challenges, where coffee is projected to face significant climate-related risks. Despite this advantage, Liberica’s market potential is hindered by difficult processing method due to its morphology, suboptimal flavor profiles, and low yield efficiency. This study investigates C. liberica beans sourced from Nawangan, East Java. An analysis of physicochemical and dimensional properties was conducted to establish baseline parameters for optimizing the roasting process, a critical determinant of flavor development. Experimental measurements evaluated variations in color, moisture content, water activity (aw), true density, porosity, and dimensional metrics across distinct roast levels. Results indicate that roasting plan differences significantly alters these parameters (p < 0.05). The minimum roasting time for Nawangan Liberica was determined to exceed 7 minutes, as samples roasted for 7 minutes exhibited a Roasting Weight Loss (RWL) of 11.805%, classified as "under-roasted." Optimal roasting occurred within the 7 - 10 minutes range, achieving RWL values consistent with industry standards (14-20%). These findings provide critical benchmarks for refining roast protocols to enhance the commercial viability of Nawangan Liberica and advance cultivation strategies for underutilized C. liberica genotypes in climate-vulnerable regions.