Effects of Ethanol and N-hexane as Solvents on the Extraction Yield of Coffee Bean Essential Oil

The primary objectives of this study were to investigate how different solvent types and solvent ratios affect both the extraction yield and quality of essential oil derived from coffee beans, with the ultimate goal of optimizing the process for higher yields and superior quality essential oil. This research was conducted in the Research Laboratory of the Chemical Engineering Study Program, where carefully weighed coffee bean samples served as the experimental material. Extraction was performed using two different solvents: 96% ethanol and n-hexane. The Soxhlet extraction technique was employed for a period of three hours, ensuring thorough extraction of the essential oils from the coffee beans. Following extraction, the mixture of coffee and solvent was subjected to distillation in order to separate and remove the solvent, thereby isolating the concentrated essential oil. Subsequent evaluation of the extracted essential oil included determining the percent yield, assessing organoleptic properties, and performing oil component analysis through Gas Chromatography Mass Spectrometry (GC-MS). The findings demonstrated that 96% ethanol provided a substantially higher extraction yield compared to n-hexane. Notably, the essential oil obtained using n-hexane appeared yellow to brown in color and possessed a very weak to weak coffee aroma. In contrast, the oil extracted with 96% ethanol exhibited a deep black color along with a slightly strong to strong coffee aroma, suggesting a richer and more desirable flavor profile. Furthermore, GC-MS analysis revealed that the total peak area of oil components extracted with 96% ethanol was 21.04%, whereas that extracted with n-hexane was only 0.95%. This pronounced disparity clearly highlights the superior efficiency of ethanol as a solvent for extracting high-quality essential oils from coffee beans. These results underscore the significant impact of solvent selection on both the yield and quality of coffee bean essential oil. Ethanol, in particular, shows promising potential for industrial applications in the production of coffee flavorings and fragrances. This study provides valuable insights into optimizing essential oil extraction processes and facilitating the enhanced utilization of coffee bean towards various commercial purposes. Key words: Solvent, Coffee, Ethanol, N-Hexane, GC-MS, Oils, Solvents, Soxhlet, Industry