Airflow Resistance of Parchment Arabica Coffee

Abstract

Resistance to airflow of clean bulk parchment coffee at moisture contents of 36·7, 30·7, 19·6 and 12·7% (w.b.) was studied for airflow range of 0·126–0·72 m3 s−1 m−2 using an experimental test column. Results indicated that resistance to airflow across a column of parchment coffee increased with increasing bed depth and airflow rate and decreasing moisture content for both dense and loose fill. Densely filled columns resulted in higher resistance to airflow. The resistance to airflow through a bed of parchment Arabica coffee has been characterised by Shedd's model, Hukill and Ives model and a model giving an empirical relationship between airflow resistance and experimental variables. It also revealed that airflow rate had the highest effect on pressure drop followed by moisture content and bulk density.