Abstract: An apparatus for measuring a dust content in a sample of granules includes an elongate vertically oriented generally cylindrical hollow tower with a bottom portion, an intermediate portion and a top portion adapted to detachably engage the intermediate portion. The bottom portion further includes collection means for collecting the granules processed through the tower. Air is recirculated through the apparatus using air recirculation means such as a blower/vacuum device. A series of valves and pressure sensing gauges for regulating and controlling the air flow are installed within the recirculation path. The tower intermediate portion further includes a plurality of horizontally oriented grates, each grate being secured in a predetermined space apart relationship. A filter is used between the top portion and the intermediate portion to trap dust blown from the granules as the granules are dropping through the grates.