A preliminary study on the feasibility of using the composition of coffee roasting exhaust gas for the determination of the degree of roast

Variations in the chemical composition profile of the gas evolved during ro asting of coffee were qualitatively monitored with the aim of further estab lishing a chemical criterion for determination of the degree of roast. Simu ltaneously, the variations in the beans physical properties, such as volume , weight loss, and moisture content, were also monitored. Three hundred gra ms of coffee were roasted in a lab-scale roaster and the optimum degree of roast was reached in 9 min. The gas evolved during roasting was collected f or gas chromatographic analysis. The chromatograms representing the evoluti on of the gas composition profile showed that a group of compounds will fir st appear close to the optimum degree of roast time. This indicated the fea sibility of using such compounds as chemical descriptors when establishing a scientific criterion for determination of the degree of roast. (C) 2000 E lsevier Science Ltd. All rights reserved.