Due to its flavor, aroma and stimulant nature, coffee becomes the second most drinkable liquid next to water all over the world. These natures develop very well during roasting, but there is a problem of partial charring and poor temperature distribution across the coffee bean due to the the low thermal conductivity of bean and overheating during roasting process; hence, there is a need for uniform temperature distribution across the roasted coffee bean. To fulfill this need, the roasting of coffee bean in a single layer packed bed arrangement using closed system circulating hot air had been employed. In this work, the export standard Limu coffee bean moisture content and raw bean values were determined and it gets roasted. During the roasting process the effect of roasting temperature (200℃, 230℃, and 260℃ ), roasting time (5-minutes, 10minutes, and 15-minutes), and particle size (4-6 mm, 2.36-3.35mm and 1.7-2.36mm) on dry mass loss, bulk density, biochemical composition and sensory attribute of the final product have been investigated. The moisture content of raw coffee bean was found to be 8.45% in wet bases, beside this the raw value scores 37.6/40. From the processing conditions 230℃ with particle size range 4-6mm shows the steady transition in terms of dry mass loss and change in bulk density with time. The maximum dry mass loss and change in bulk density were 33.14% at a processing condition of 260℃ for 15minutes and 2.36-3.35mm and 30.9% for 260℃ for 15-minutes for 4-6mm respectively. The sensory attribute analysis marks that no single processing condition gives every desired cup values, so the best one is selected from of the cumulative roasting cup values and found to be 89.21 at processing condition of 230℃ for 10-minutes for 46mm. The caffeine result shows a maximum of the caffeine content of 55.5mg/250ml can be achieved at a processing condition of 230℃, 10-minutes, 2.36-3.35mm particle size.