DEVELOPMENT OF COFFEE ROASTING BY USING FAR INFRARED RADIATION TECHNIQUE

Abstract

In this research, aimed to study the heat transfer mechanism of FIR heater for coffee roasting and the effect of far infrared radiation on the quality of coffee beans such as FIR power, roasting temperature, and roasting time was investigated and compared with the hot air roasted technique. Coffee bean 1,000 gram was roasted in Horizontal roaster coffee machine with different FIR emitter power 1,000, 1,500, 2,000, 2,500 and 3,000 watt without preheating the roasting drum. The roasting temperature and time with temperature at 260oC refer to green coffee bean surface were measured. The moisture content of coffee bean is 9%db and air velocity 0.03 m/s. The result showed that the effect of radiant heat has a greater influence on coffee roasting than the effect of convection and the heat radiation in the case of more surface area has a higher radiation value and takes less time to roasting coffee with less surface area. At 2500 watts, the heater power is suitable for roasting coffee. Because coffee can be roasted in 20 minutes, the brightness of the coffee corresponds to the color of roasted coffee obtained from the reference coffee color and within the criteria acceptable to consumers and requires a specific energy of 3750 j/g compared to other heaters. It was determined that roasted coffee could benefit from the usage of Far Infrared (FIR) heater.

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