Finding Fresh Paths for Whiskey Stillage

Distilleries are growing and multiplying, but there are only so many cattle to eat the spent grains. As the whiskey industry expands, meanwhile, Kentucky is a hotbed for innovation in uses for stillage.

Hollie Stephens Feb 19, 2024 - 9 min read

Finding Fresh Paths for Whiskey Stillage Primary Image

Photo: Craft Spirits & Distilling

Conventionally, distillers have given their stillage—the wet-grain waste left from the mashing process—to farmers for use as animal feed, offering a source of protein for cattle. However, as the whiskey industry continues to grow—and with it the number of smaller craft distilleries—producers will need to identify new destinations for their spent grains.

According to the Kentucky Distillers Association, bourbon production has increased by more than 360 percent in the past quarter-century. Meanwhile, there are fewer cattle in the state than there used to be. Without a plan, distillers could be left with more waste than they know what to do with. However, help may be at hand: This looming waste problem is fueling innovation in how to use this industry by-product.

“There’s a lot of technology out there at different stages,” says Dr. Brad Berron, associate professor of chemical engineering at the University of Kentucky. He coordinates the research activities within the university’s James B. Beam Institute for Kentucky Spirits.

Berron highlights some of the interesting new uses that have been developed for stillage, including as a substrate for growing high-value mushrooms and as an ingredient in a high-fiber, low-carb puffed corn snack. “There’s all these opportunities that are coming along just because we’re getting the right intellectual minds focused on this problem.”


One big challenge is that stillage is cumbersome to transport: It’s typically more than 90 percent water. It also spoils quickly, especially in warmer weather. “From a practical standpoint, most farmers don’t consider it reasonable to pick it up beyond 50 miles,” Berron says.

Larger distilleries have dry houses to remove moisture from the grain before transporting it, but this is an energy-intensive process. Meanwhile, smaller craft distilleries that have no such equipment are growing in number. Thus, it would be ideal to have more ways to offload wet stillage.

Berron points to another challenge on the craft level: the lack of stability in chemical composition. “What they’re doing on a day-to-day basis can change a lot.”

New Technology Levels Up

In 2021, the Beam Institute partnered with various organizations to host the Reverse Pitch competition, where innovators with ideas for stillage solutions submitted their ideas. The competition helped attract attention to the impending challenge of spent grains in Kentucky, while highlighting the opportunities for companies that can provide solutions.

The companies delivering their pitches included SoMax Circular Solutions, which uses hydrothermal carbonization (HTC) to recover valuable by-products from spent grains. Another was LocalSols, which transforms spent grains into raw proteins that can be used in premium pet and plant foods.


The competition winner, however, was BioProducts. The company uses stillage to make two very different products: xylose, a low-calorie sweetener; and activated carbon, which has applications for battery cells and is the preferred electrode material in supercapacitors. That multi-product approach allows the company to extract as much value as possible from the stillage that might otherwise go to waste.

BioProducts founder and CEO Jagannadh Satyavolu aims to be part of helping the spirits industry improve its sustainability processes in a way that makes sense financially as well as environmentally. “Our approach is to set up these plans right at the distillery,” Satyavolu says. He notes that having trucks haul away large volumes of stillage for many miles also contributes to greenhouse gases.

Louisville’s Rabbit Hole is one distillery already working with BioProducts to process its stillage. The BioProducts facility is just a mile and a half from the distillery, making the transport simple. “We work with one of our local farmers … who is able to haul it over,” says Cameron Talley, director of operations. Once the team removes the spent grain, they use a screen to allow thin stillage to fall through, for recycling back into cooks and fermentation, before pumping the stillage to a bulk tanker for transport to BioProducts.

Sustainable Grain Processing Supports a Growing Industry

As whiskey production in Kentucky and elsewhere continues to boom, innovation in stillage processing seems set to continue.

“If we’re going to grow our business, that means there’s going to be more of this material,” says Andy Battjes, director of global sustainability at Brown-Forman, one of the world’s largest wine and spirits producers and owner of Jack Daniel’s. “There has to be a way to manage it that is cost-effective and, where possible, has a reduced or even positive impact.”


When deployed at scale, programs that focus on sustainably managing spent grain can make a big difference to the environment—but they can also make a big difference to the efficiencies at distilleries.

One large-scale example is the Jack Daniels collaboration with 3 Rivers Energy Partners to install an anerobic digestor. The facility will use spent grain to produce renewable natural gas as well as a low-carbon natural fertilizer that will be available to local farmers.

“We’ll be using a pipeline to send the by-product from the Jack Daniels distillery, that they’ll convert … into biogas,” Battjes says. The partnership will allow the distillery to continue to expand its production without having to spend more on expanding their energy-intensive dry house. Once operational, the new facility is expected to produce up to 1.1 million MMBtus of renewable natural gas annually.

Even beyond the digestor project, Battjes says he remains interested in the newer innovations in processing stillage. “We’re doing a lot of investigation and monitoring,” he says, adding that there is no shortage of companies and researchers who have ideas. “We’ve supplied stillage samples to several different research groups over the years.” He says they are focused on partnering with companies that can take on the management of the material as a service. “That’s essentially what you’re paying for,” he says.

For companies that can process the spent grain, the financial incentives and opportunities are compelling. “Distilleries are having to really consider what’s going to happen with their spent grains before they can open up,” Berron says. This pressure means that some distilleries are willing to pay something to get rid of spent grain, and organizations able to process it can capitalize by obtaining a value feedstock for free.

Forming the Right Relationships

“If we’re going to enter into some sort of an agreement with somebody, there’s a lot of conversations about ‘what’s the backup plan?’” Battjes says. This could mean putting some flexibility into processes in case a partner is unable to accept by-products for some period of time. He also points to the importance of making sure operations have been fully permitted by local agencies, including business and environmental agencies.

“It’s exciting that a lot of distillers are taking chances on new pilot technologies,” Berron says, but he emphasizes the importance of caution and care on both sides when entering into new working relationships. He says he wants the technology companies to understand that operational challenges and changes on their side can be disastrous for distillers—and they could even cause a distillery to go under because they have no sustainable outlet for their spent grains.

If distillers break off relationships with local farmers in favor of working with another organization, they might not be able to get those relationships back overnight if things don’t work out. “I think that’s something that we’ve had a lot of trouble getting technology companies to understand,” Berron says. “This is a reason why so many distillers are really hesitant to really go all-in on a new technology. If it goes bust, it has a very significant impact on your ability to produce bourbon.”

Keeping multiple avenues for stillage—including some traditional relationships with farmers—can be a way to mitigate this risk for distillers exploring new channels for their waste. “We still run a little bit of a hybrid model,” says Talley at Rabbit Hole, “just so that we have different avenues or options, and we don’t jeopardize production.”

Hollie Stephens is an award-winning journalist based in New Mexico and originally from the United Kingdom. Her work has been published in Craft Beer & Brewing Magazine®, Brewer and Distiller International Magazine, Wine Enthusiast, and many other publications.