Carbon Dioxide Evolution and Moisture Evaporation During Roasting of Coffee Beans

摘要

Evolution of carbon dioxide and water vapor during roasting of coffee was followed in an isothermal high-temperature short-tune and a low-temperature long-time roasting process. In addition, CO_2 release during storage of roasted beans was followed. CO_2 and water vapor concentration were assayed in the exhaust air by nondispersive infrared gas analysis. Although CO_2 evolution rates differed in the 2 processes, the final total amount of CO_2 released after 63 d of storage remained equal. CO_2 evolution and differentiation between evaporation of initial water and chemically formed water showed that chemical reactions leading to relevant amounts of CO_2 and water start at approximately 180℃. A mass balance established on the present measurements was able to account fairly well for the gravimetrically measured roast loss.