Heat of Combustion of Dried and Undried Coffee

Globally, over two billion cups of coffee are consumed per day. During roasting, 15-20{\%} of the weight of the coffee beans is lost. We studied the gasses released during the roasting process using an IR spectrometer and identified the evaporation profile of water as a function of temperature. The heat of combustion (H\textordmasculine c) of the beans was also determined using an Isoperibol Oxygen-Bomb calorimeter and the H\textordmasculine c of dry beans were determined to be 21.24 \textpm 0.13 MJ/kg while the H\textordmasculine c of the wet beans were determined to be 19.56 \textpm 0.12 MJ/kg. This study can potentially lead to developing more economical and environmentally friendly techniques of roasting coffee beans.