The BakkerArkema model for grain drying in deep beds was modified to simulate the process of coffee dryingusing a proposed thinlayer equation that had been adapted for parchment coffee. A proposed empirical thinlayer modelwas incorporated into the deepbed coffee drying model. A prototype coffeebean drying bin was tested in the AgriculturalExperimental Station in Adjuntas, Puerto Rico, and used for validation of the mathematical model. The model predicted themoisture level of the beans with a maximum deviation of 3% (w.b.) throughout the drying process. The airflow direction wasreversed in 3 or 6hour intervals, and the drying air temperature was 55 C. The initial moisture content was 55% to 56%(w.b.). Twentyseven hours were needed to reach a moisture level of 11% w.b. using an airflow rate of 15.24 m3 m2 min1.