A recent study by Purdue University (USA) scientists shows that "biofuels processors who mill switchgrass into fine bits to help its flowability should be able to save time, energy and money by not doing so". (Switchgrass, Panicum virgatum, is a potential lignocellulosic feedstock for biofuel ethanol production). The Purdue Universty study "investigated the particle size, particle size distribution, and morphological changes of three biofeedstocks (switchgrass, corn kernels, and soybean seeds) ground by hammer-milling through three screen sizes (6.4 mm, 3.2 mm, and 1.6 mm). They found out that "while [hammer-milled] corn and soybeans are round and spherical, switchgrass is shaped more like matchsticks, causing pieces to interlock and disrupt its ability to flow, according to Assistant Professor and co-researcher, Klein Ileleji. "Blockage" is reportedly not good in any biofuels processing facility. Switchgrass is not a good "flowable" feedstock, and grinding does not necessarily change its morphological characteristics that are important for flow. Assistant Professor Ileleji says that processors could save money if they can stop hammer-milling switchgrass when it fits through a 6.4 mm screen. Details of the study are published in the journal, Transactions of the ASABE (American Society of Agricultural and Biological Engineers) (URL above)..