Now coffee could fuel cars too

Scientists have made biofuel from ground coffee produced in 20 different geographic regions — including caffeinated and decaffeinated forms.

New research from the University of Bath suggests that waste coffee grounds could be a “sustainable fuel source” for powering vehicles.

The study found that different varieties of coffee, including Robusta and Arabica, have reasonably standard composition and relevant physical properties of fuel.

This means all coffee waste could be a “viable” way of producing bio- diesel, scientists from the University’s Centre for Sustainable Chemical Technologies said.

Waste produced from the average coffee shop — around 22lb each day — was found to produce about two litres of biofuel.

Chris Chuck, Whorrod research fellow at the university, said the research highlighted the potential for waste coffee to be a “truly sustainable” bio-fuel.

“Around 8m tonnes of coffee are produced globally each year and ground waste coffee contains up to 20% oil per unit weight,” Dr Chuck said.

“This oil also has similar properties to current feedstocks used to make bio-fuels. But, while those are cultivated specifically to produce fuel, spent coffee grounds are waste.

“Using these, there’s a real potential to produce a truly sustainable second- generation biofuel.”

Oil can be extracted from coffee grounds by soaking them in an organic solvent, before using a process called transesterification to transform them into biodiesel.

The University of Bath study examined how fuel properties depend on the type of coffee used. It found all waste coffee grounds has reasonably standard composition and relevant physical properties, irrespective of source.

“The yields and properties of biodiesel can differ depending on the growth conditions of current bio- diesel feedstocks, sometimes causing them to fall out of specification,” Dr Chuck added.

“The uniformity across the board for the coffee biodiesel fuel is good news for biofuel producers and users.”