challenges and opportunities for
Utilizing Spent Distillers Grains and Stillage
Preliminary results from a focused initiative Kurt A. Rosentrater
Stillage and Distillers Grains A Growing Issue
Executive Director, Distillers Grains Technology Council Associate Professor, Iowa State University Faculty Fellow, James B. Beam Institute for Kentucky Spirits Phone: (515) 294-4019; karosent@iastate.edu
Brad J. Berron The beverage alcohol industry is currently experiencing unprecedented Research Director, James B. Beam Institute for Kentucky Spirits growth throughout the United States. In conjunction with this expansion, Associate Professor, Chemical and Materials Engineering , University of Kentucky the quantity of spent grains (in many forms, including stillage, wet grains, and dry grains) produced over time has grown in parallel. After all, fermenAmanda LeFevre tation uses the starch, not the protein, fat, fiber, or mineral components. Deputy Commissioner, Kentucky Department for Environmental Protection For large distilleries, drying the stillage into distillers’ dried grains (DDG) Kari Johnson and selling it as livestock feed can be a viable option. For smaller distillEnvironmental Consultant, Kentucky Departeries, selling the wet grains to livestock farms has been found to be effecment for Environmental Protection tive as well. For some urban distilleries, however, these options may not Don Colliver be cost-effective, so disposal to the city sewer system has been common Professor, Biosystems and Agricultural Engineering , University of Kentucky practice. Unfortunately, increasing environmental impacts and increasing Associate Director, Kentucky Industrial Assessment Center water-treatment costs are making these disposal options less attractive. Faculty Fellow, James B. Beam Institute for Kentucky Spirits This industry has continually evolved over many generations, and technological innovations and process changes continue to be implemented to improve process efficiencies, but these can also affect the resulting co-product streams. As a consequence, new questions, challenges, and opportunities for utilizing stillage and spent grains have arisen. As the quantity of these materials continues to grow, it is vital that these issues are addressed, so that value-added uses for these co-products continue to be developed, commercialized, and augmented — especially as the number of distilleries continues to grow throughout the U.S. Understanding the constellation of issues surrounding stillage and spent grain use is an essential step that must be undertaken as this industry continues to grow. In order to determine the needs of the companies that produce distillers grains, as well as the customers that may utilize them, three primary questions should be asked: 1. What are the major issues that currently impact or have the potential to affect the value and use of stillage and spent distillers grains over the next several years? 2. What research should be conducted to address these issues? 3. What are the priorities for this research?
Figure 1 Typical whole stillage dropped from a fermentor, ready for some type of value-added use. Every distillery will have unique whole stillage solids/moisture, physical properties, and chemical properties due to a variety of mash bills and production practices used. 116
To answer these questions, the Distillers Grains Technology Council (DGTC) and Iowa State University have teamed up with the James B. Beam Institute and University of Kentucky, as well as the Kentucky Department for Environmental Protection, to conduct surveys, hold discussion sessions, and facilitate focus groups. Input has been solicited from beverage alcohol producers, technology and equipment providers, commodity and trade groups,
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