Aluminum in Coffee

Jakob Windisch; Bernhard K Keppler; Franz Jirsa

doi:10.1021/acsomega.0c01410

Aluminum in Coffee

ACS Omega. 2020 Jun 15;5(25):15335-15343. doi: 10.1021/acsomega.0c01410. eCollection 2020 Jun 30.

Authors

Jakob Windisch¹, Bernhard K Keppler¹, Franz Jirsa^{1

2}

Affiliations

¹ Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090 Vienna, Austria.
² Department of Zoology, University of Johannesburg, P.O. Box 524, Auckland Park, 2006 Johannesburg, South Africa.

Abstract

This study investigated the aluminum content in one of the most consumed daily beverages: coffee. The total Al concentration in 10 different samples of coffee beans and their water-extractable fraction were determined. We then tested the influence of different brewing methods on the concentration of the extracted Al in the final beverage. Metal analyses were performed using graphite furnace atomic absorption spectroscopy (GF-AAS) after microwave-assisted acid digestion. The results showed highly variable Al contents in coffee beans (1.5-15.5 mg kg^-1), of which ∼2-10% were water-extractable. The brewing technique had a major influence on the Al content in the beverage: significantly higher Al concentrations (72.57 ± 23.96 μg L^-1) occurred in coffee brewed in an aluminum moka pot. Interestingly, using ground coffee with this method even reduced the Al content in the final beverage compared to the brewing water used. Coffee brewed from Al capsules did not contain significantly higher Al concentrations compared to other methods.