A professor of engineering, Mano Misra, has been credited with having recognized the propensity in used coffee grounds to be made into biodiesel. As the story goes, he unknowingly left a cup of coffee sitting overnight and the next day noted that the cup had a floating layer of oil. Thus, the question of whether or not used coffee grounds would contain an amount of oil that would be of interest to convert into biodiesel was arose. With the assistance of his United States based research team at the University of Nevada, he collected approximately 50 pounds of used coffee grounds from various Starbucks locations. Together, the scientists set out to confirm whether or not the grounds contained a valuable quantity of oil.

They found that the grounds included up to 15% of oil by weight, and then proceeded to successfully extract the oil through a standard transesterification process. The extraction is said to have been easy and economical. In conclusion, they have estimated that in the best of scenarios only 1% of the fuel required in the United States alone could be produced from this process. However, while this may not be the end all be all answer to the fuel issue, it may very well prove to still be worthwhile. If the focus is to make add this one feedstock into a collection of other feedstocks, then there is a place for this method. If the objective is to make fuel from waste materials then it is possible for this to work in conjunction with other feedstocks. Over 16 billion pounds of coffee is produced in the world annually, thus there is a consistent and inexpensive supply of coffee waste available. Plus, the remaining solid waste left over after the extraction can be further made use of as compost, or fuel pellets. In addition, it has been estimated that an annual profit of over 8 million dollars could be made from the biodiesel and the pellets from just one large coffee chain. However, if we were looking for one source to single-handedly eliminate the fuel problem, then coffee grounds would not be the answer.

Since the completion of this research, pilot operations to collect used grounds and extract the oil have been planned. There will undoubtedly be ongoing research conducted in this field, and many interested parties will be waiting for those results.

External Resources:

• arstechnica.com
• guardian.co.uk
• nytimes.com