Bourbon Distilleries: A New Source of Renewable Energy

In Kentucky, the demand for bourbon is expected to double over the next five years, while the state’s cattle population has reached its lowest level since 1951. These two facts could come together to transform bourbon distilleries into a new source of biofuels.

At the end of the bourbon distillation process, a substance known as “stillage” remains. This protein-rich material consists of the grains used to feed the yeast responsible for fermentation, along with dead yeast cells and other byproducts of the process. Typically, it is used as feed for cattle and other livestock. In 2020, Kentucky alone produced 127.2 million gallons of bourbon, and for every gallon of the spirit, ten times as much stillage was generated.

Environmental Challenges of Stillage Transportation

While repurposing stillage as animal feed helps reduce waste, transporting it comes with a significant carbon footprint. Sometimes, stillage is processed to separate solids from liquids and refined into a syrup that enhances existing feedstocks. However, this process is energy-intensive, and many small-scale distilleries—responsible for 60% of production in Kentucky—lack the capacity to implement it.

Additionally, the U.S. cattle herd is at its lowest level since 1951, according to the U.S. Department of Agriculture. This makes using stillage as animal feed increasingly less viable for bourbon producers.

Seeking a more efficient use for this byproduct, researchers at the James B. Beam Institute for Kentucky Spirits explored converting it into methane, a natural gas.

Grain Composition Influences Methane Yield

Since stillage comprises a blend of grains—including corn, barley, rye, and wheat—the scientists conducted experiments to assess how different combinations of these grains reacted when digested by anaerobic bacteria. They found that blends with higher rye content produced less methane, while those with higher corn content yielded the most methane.

Methane, when released into the atmosphere, contributes to global warming. However, when burned, it is more efficient and emits less carbon dioxide than popular fuels like gasoline and coal. This makes it a “cleaner” energy source. Converting stillage into methane could enable its use to power distilleries, fuel trucks, heat homes, or generate electricity.

“This study demonstrates that distilleries can not only mitigate the environmental burden of excess stillage but also create a circular system where waste is turned into fuel,” explains Tyler Barzee, assistant professor of Biosystems and Agricultural Engineering at JBBI. “This is a local solution that could position Kentucky as a leader in both bourbon production and renewable energy.”

Read the original article on: New Atlas

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