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Turn Spent Coffee Grounds into Biodiesel

By Hank Will, Editor-in-Chief


Tags: biofuel, biodiesel, machinery, ,

Hank WillIt used to be that we just put used coffee grounds in the compost heap or directly into the garden, but now it seems that used coffee grounds make a great feedstock for making biodiesel. I have just gotten used to the smell of french-fries emanating from the tail pipes of  some city buses and a few pickup trucks … the smell of coffee might be more than I can handle.

According to a study carried out at the University of Nevada Reno, coffee, the dregs of most used beverage in the world have value as an oil source for the production of high-quality biodiesel. In an article published in the March issue of Biodiesel Magazine, Susanne Retka Schillthe reports that the concept of using coffee to produce diesel fuel has been around for a few years anyway. It seems that bio-fuel pioneers down in Brazil have been using excess and reject coffee beans to make biodiesel for some time now. The new research indicates that used coffee grounds contain from 11 percent to 20 percent oil that results in a stable, but sulfur-rich biodiesel. In order to meet ASTM standards for on-road diesel fuel, the sulfur needs to be removed first.

 Vegetable oil can be an alternative fuel.

the University of Nevada, Reno study concluded that if all the coffee grounds were collected from Starbuck’s they could be processed into about 2.9 million gallons of biodiesel each year. And once the oil is extracted from the coffee grounds, the remains can be turned into pellets and used as a heating fuel. The scientists working on the project realize that coffee grounds can really only amount to a small fraction of fuel needs globally, but I believe that their work is important because it makes clear that solutions to our fuel issues can be found in unlikely places, if only we can see them.

I know I would gladly run coffee biodiesel in my tractors and pickup, if I could find it. It makes more sense to me to take a waste product and turn it into biodiesel than it does to grow a crop like soybeans just for that purpose. What do you think?


Hank Will raises hair sheep, heritage cattle and many varieties of open-pollinated corn with his wife, Karen, on their rural Osage County, Kansas farm. His home life is a perfect complement to his professional life as editor in chief at GRIT and Capper's Farmer magazines. Connect with him on .