A Comparison of Measurement Procedures Used to Determine the Bulk Density of Distillers Dried Grains with Solubles (DDGS)

The production of corn-based ethanol in the U.S. has been dramatically increasing in recent years, and consequently so has the quantity of co-product, distillers dried grains with soluble (DDGS) generated from this processing sector. DDGS is sold as a commodity for animal feed and like corn; its bulk physical and chemical properties are quality attributes normally used in trading by merchandisers. Consistency in product quality have been cause for concern in the industry and the lack of standard methods for physical and chemical property determination does potentially confound the issue, especially when results of attributes measured by different methods have not been evaluated for method parity. This research examined bulk density measurements of DDGS, using DDGS from six commercial ethanol plants (three from Indiana, and three from South Dakota) and conducted in two different labs. The effects of sample handling, measuring container filling method, filling height and measuring container size were examined. Variations due to each of these factors were quantified, it was determined that filling height and measuring container caused significant difference in the bulk density measured. As a guide for the standard method of determining bulk density for DDGS, we recommend the combination of a short drop height, using a 1 L measuring cup, with the sample obtained using a Boerner divider.