Carbon Dioxide Evolution and Moisture Evaporation During Roasting of Coffee Beans

Abstract

ABSTRACT: Evolution of carbon dioxide and water vapor during roasting of coffee was followed in an isothermal high‐temperature short‐time 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 ap ‐proximately 180°C. A mass balance established on the present measurements was able to account fairly well for the gravimetrically measured roast loss.