Aluminum in Wine - Its Measurement and Identification of Major Sources

¹ School of Science and Mathematics, University of Melbourne, Parkville, 3052, Australia
² Centre for Scientific Instrumentation, La Trobe University, Melbourne, 3083, Australia.

Aluminum levels in wine were found generally to fall below the normal working range of flame atomic absorption spectrometry and above the linear working range for graphite furnace atomic absorption spectrometry. Graphite furnace atomic absorption spectrometry was selected as the preferred method. The analytical procedure requires the dilution of the sample to reduce the aluminum concentration to within the linear working range, and this was shown to have the advantage of overcoming matrix effects on the analysis. From a survey of 267 wines, it was shown that white wines and sparkling wines have a slightly higher mean aluminum concentration than red wines or fortified wines. From a study of juices and wines at various stages of winemaking, it was observed that the addition of bentonite was a major source of aluminum contamination, with increases of 100% common after bentonite treatment. Other sources of aluminum which were identified were contact with the metal, pad filtration, and red tannin.

Key words: aluminum, graphite furnace atomic absorption spectrometry, wine, bentonite, wine additives, wine processing

Submitted on May 21, 1991