Used coffee grounds turned into biodiesel

That morning cup of coffee may get you going in more ways than you think.

Many people rely on caffeine in coffee to jump-start their workday. Used coffee grounds may one day help power your car as you drive to work.

University of Missouri students collected used coffee grounds from kitchens and turned the oil from them into biodiesel.

Their project was part of ongoing research into using alternative feedstocks such as vegetable oils, used cooking oils and gasified shredded tires to produce biodiesel fuel. Biodiesel from these treated feedstocks is fed into diesel test engines to measure performance and efficiency.

The oil in coffee grounds is extracted by a standard method that uses hexane as a solvent. The oil content of spent coffee grounds is almost 14 percent.

“The properties of the coffee oil are similar to the properties of soybean oil, the major source of biodiesel,” said Bulent Koc, MU assistant professor of agricultural systems management.

Solids remaining after the conversion can be converted to ethanol or used as compost.

In addition to coffee, other vegetable oils tested include soybean, sesame, palm and peanut oils.

Coffee is ubiquitous in many cultures. Growers produce more than 16 billion pounds of coffee each year, according to the National Coffee Association. The three top producers are Brazil, Vietnam and Colombia.

Used coffee grounds have high moisture content, so collected grounds are dried before extracting the oil. Current research seeks to bypass the drying process to save time and energy.

Biodiesel from coffee extractions would represent a small portion of the growing biodiesel market. Some scientists estimate that spent coffee grounds can potentially add 340 million gallons yearly to the world’s fuel supply.