August 16, 2021 | By: Aimee Nielson
LEXINGTON, Ky.

Distillers  use massive amounts of grains like corn, rye, wheat and barley to create bourbon, Kentucky’s signature spirit, and other whiskeys. That creates a lot of byproduct distillers refer to as spent grains, or stillage. The University of Kentucky’s James B. Beam Institute for Kentucky Spirits is conducting several studies to help figure out how to use all that spent grain and institute faculty will serve as judges in an upcoming contest to find innovative solutions.

“With Kentucky producing 95% of the world’s bourbon, spent grains are a significant issue in our state,” said Brad Berron, director of research for the Beam Institute. “Our distilleries want to be responsible stewards of their resources. They want us to come alongside them and find real solutions.”

Distillery numbers are up 250% in the past 10 years according to the Kentucky Distillers’ Association. KDA reports that for every gallon of bourbon produced, 10 gallons of distilling byproduct or whole stillage, a mixture of water and mash that remains after ethanol evaporates, is left. That equals a mind-boggling one billion gallons of whole stillage from Kentucky distilling operations.

The Beam Institute is partnering with the Kentucky Distillers’ Association, Team Kentucky Cabinet for Economic Development, Distillers Grain Technology Council, KY INNOVATION, Kentucky Energy and Environment Cabinet and innovation incubated to sponsor the Distillers Grains Reverse Pitch. Through this effort, the collaborators are seeking new and innovative technologies and solutions from problem solvers, inventors, entrepreneurs and businesses to expand uses of  stillage. The group will choose five to six solutions to formally present at the Distillers Grains Symposium on Oct. 25.

Berron said some low-tech solutions are already in play. For many years, livestock producers have been primary users of stillage for feeding their herds. Larger distilleries have invested in equipment to dry out whole stillage and make it more portable, but smaller craft distillers don’t always have the funds for that. Either way, stillage has nutritional value for livestock.

Bourbon distilleries have provided beef producers with valuable feedstuff for centuries. 

“The most recent ethanol boom in the Midwest which began in the early 2000’s greatly increased access to spent grains from the production of ethanol changing feedlot diets,” said Jeff Lehmkuhler. beef specialist in the UK College of Agriculture, Food and Environment.  “The production of fuel ethanol and ethanol for bourbon are essentially identical.”

UK associate professor Eric Vanzant conducted research that has shown similar performance for stocker cattle receiving fuel or bourbon-derived dried distillers grains.  However, Lehmkuhler said the drastic expansion of bourbon production has not yet resulted in investment in dewatering technology, leading to large quantities of whole stillage.

Whole stillage is what is left after the ethanol evaporates out and only water and mash remain. Feeding it wet replaces some of the water cattle would normally drink. It’s a great source of protein and energy for cattle.

“Whole stillage contains nearly 93% water making it a challenge to transport and feed,” Lehmkhuler said. “It is too costly to haul water down the road and whole stillage is a locally available feed resource. In many instances, this is problematic as distilleries are constructed in urban areas with few cattle nearby to utilize the stillage as feed.” 

The fuel ethanol industry and larger bourbon distilleries have invested in driers allowing the dried product to be a marketable feedstuff across the United States and beyond. In the 1940s, UK researchers initially investigated feeding stillage to beef cattle but limited feeding research has been conducted since. 

“Additional research is needed to increase our understanding of how stillage may impact fermentation in the rumen and overall animal health allowing us to refine feeding recommendations to the beef industry in the region,” Lehmkhuler said.

Don Colliver is the director of the Kentucky Industrial Assessment Center, housed at UK. His team has been working to determine how energy flows through distilleries.

“In particular, we are looking at various ways of processing the stillage, or that material that comes out of the bottom of the still,” said Colliver, who is also a professor of biosystems engineering in the UK College of Agriculture, Food and Environment. “We have conducted energy audits at six distilleries and identified ways that they might be able to save energy.”

Rodney Andrews is the director for the UK Center for Applied Research and a professor of chemical engineering. The center has a strong program in carbon materials research. They are actively studying stillage solutions.

“We are looking at converting stillage through a process called hydrothermal conversion,” Andrews said. “Basically, you’re heating the stillage under pressure and it will rearrange itself into what’s called ‘char’ and at that point, it’s really not stillage anymore. It becomes a very high-carbon product that can be used by itself or further processed into porous or conductive carbons.”

Andrews said the center is working with Carbon Science Solutions, a company that has optioned the technology, and several distillery partners to explore products that can be made from hydrothermal conversion.

“There’s a wide range of products we are looking at, including those that would aid in purification, cleaning up a water stream, product stream,” he said. “Other products could be used for energy storage if they are high-purity carbons. There is also implication for agriculture and building materials. We have so much to explore.”

Berron said he believes the best solutions will come from collaboration and they will be diverse.

“We will likely end up with many answers and have some kind of interconnected web of stillage solutions,” he said. “Research within the university is already very multidisciplinary and comes from many colleges across campus. We are really looking forward to the submissions and we can’t wait to work with these folks and share our work with the state’s distilleries. Every spirit has a byproduct and this competition will elevate the technology and our capability to solve the issue in ways that will fit all kinds of productions scenarios.”

For more information about the Distillers Grains Reverse Pitch, visit http://bourbonreversepitch.com.

The James B. Beam Institute for Kentucky Spirits ensures the welfare and prosperity of Kentucky’s spirits industry. Through teaching, research and outreach, the Institute promotes economic sustainability, environmental stewardship and responsible consumption. The Beam Institute is a multidisciplinary effort of experts from the UK College of Agriculture, Food and EnvironmentCollege of EngineeringCollege of Arts and Sciences and the Gatton College of Business and Economics.   

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