A foodstuff air treatment device includes a housing (1) with an elongated trough (11) for receiving the foodstuffs to be treated. The trough extends through the housing and includes a foraminated bottom (15), a first side wall (17), and a second side wall (15). A heat exchanger (12) is disposed in the housing, and a fan assembly (13) is also disposed within the housing for producing an air flow that circulates through the heat exchanger, up through the trough, and back to the heat exchanger. One side wall (17) of the trough is adjustable, laterally to the length of the trough, for changing the width of the trough.