Multivariate analysis of soluble compound extraction efficiency from coffee under cold brew conditions

The aim of this study was to evaluate the efficiency of soluble compound extraction from coffee using three cold brew process variants, addressing both technological and environmental aspects of this production method. Experiments were conducted with a custom-designed extraction basket and a forced-flow liquid system to ensure uniform raw material extraction. The process was carried out at temperatures not exceeding 30 ◦C, and the concentrations of total dissolved solids (TDS) and extraction yield (EY) were analyzed. Results showed that secondary extraction recovered up to 31.8% of the initial TDS, while replacing water with an enriched extract improved efficiency by 36.2%. The highest EY values (above 26%) were obtained in multistage variants, with a maximum TDS concentration of 2.65%. A short, 3–4-minute secondary extraction ensured effective performance, reducing the total process time to approximately 60 minutes – much shorter than the traditional 24-hour cold brew method – without loss of efficiency. The shorter process duration and its operation under low-temperature conditions can potentially improve efficiency and help reduce energy and water consumption, which in turn may also contribute to enhanced sustainability and resource efficiency in cold brew coffee production.