Air gasification research on low bulk density biomass materials is being conducted utilizing an exploratory downdraft gasifier system. One method to enhance gasifier system performance is the preheating the gasifying air. To date, gasifying switchgrass with an incoming air stream at ambient temperatures (19°C and 31°C) and at 200°C have been evaluated. Preliminary results show that using preheated air drastically increases the temperatures in the twin-shelled pyrolysis section of the reactor, resulting in improved cyclonic combustion of pyrolysis gases. Producer gas tar contents reduced from 16.7 to 12.5 g/Nm3 as the gasifying air temperature increased from 30°C to 200°C. However, marginal differences were observed in the concentration levels for CO (15.6 to 16.2%) and H2 (10 to 11.2%). Experimental setup and test results obtained so far will  be presented.