Distillers dried grains with solubles (DDGS), a co product of the corn-based fuel ethanol industry, is used widely as an animal feed. Due to increased demand for DDGS in livestock markets it has become essential to transport DDGS over long distances. Flowability problems in DDGS, due to particle caking, often create nuisance in storage and transportation. Materials above the glass transition temperature (Tg) can exist in a “rubbery state,” this condition can often be responsible for structural collapse, particle agglomeration, and caking of materials. This study investigated the effects of varying CDS (10, 15, and 20%, wb), drying (100, 200, and 300°C), and cooling temperature (-12 and 35°C) levels on the Tg of DDGS. Tg was found to range from 34 to 58°C and 41 to 59°C for cooling temperatures of -12°C and 35°C, respectively. Results indicated that there were significant differences due to the levels of CDS, drying, and cooling temperatures, individually as well as simultaneously. There were also significant interaction effects. Response surface regression yielded a predictive model with R 2 of 0.74 and SEM of 3.16. Using this regression equation, optimum ranges for drying and cooling temperatures were determined for various ambient conditions. These may be used to avoid flow problems.