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An innovative method of extraction of coffee oil using an advanced microwave system: in comparison with conventional Soxhlet extraction method

Hibbert, Sam; Welham, Kevin; Zein, Sharif H.


Sam Hibbert

Kevin Welham


The production of energy and chemicals from waste biomass is an attractive alternative by comparison with first generation biofuels and fossil feedstocks. This paper investigates oil extraction from spent coffee grounds (SCG) by means of an advanced microwave process and compares this with a conventional Soxhlet extraction (SE) method. Microwave assisted oil extraction (MAE) from SCG was performed over different durations, varying solvent volumes and extraction temperatures. It was found that each of these parameters had an effect on the process, with the largest yield being over 11.54 wt %, oil extracted in 10 minutes using 160 ml of hexane at 95 oC. In 10 minutes, MAE was successful in extracting more oil than SE. MAE achieved a 24 fold decrease in duration for the extraction compared with SE and used less solvent per gram of oil produced. It is proposed that a certain moisture content in the SCG would be beneficial to the extraction process and might it also play a role in the heating process. The extracted oil can be converted into biodiesel and biochemicals leaving the remaining solids suitable for processing into bioethanol, fertiliser, adsorptive material and fuel pellets.


Hibbert, S., Welham, K., & Zein, S. H. (2019). An innovative method of extraction of coffee oil using an advanced microwave system: in comparison with conventional Soxhlet extraction method. SN Applied Sciences, 1(11),

Journal Article Type Article
Acceptance Date Oct 3, 2019
Online Publication Date Oct 24, 2019
Publication Date 2019-11
Deposit Date Oct 2, 2019
Publicly Available Date Oct 25, 2020
Journal SN Applied Sciences
Electronic ISSN 2523-3971
Publisher Springer (part of Springer Nature)
Peer Reviewed Peer Reviewed
Volume 1
Issue 11
Article Number 1467
Keywords Coffee oil; Extraction; Microwave; Soxhlet; Spent coffee grounds
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© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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