The Australian Wine and Brandy Corporation (AWBC) has recommended that legal proceedings be initiated against the Riverland winery Kingston Estate following the discovery that “small quantities of silver nitrate had been added to some wines that had been exported.” The legal action follows investigation of claims by two American work exchange students that Kingston Estate had added a prohibited substance, silver nitrate, to wine and that contrary to regulations, grape tannins were used to colour sultana grape juice to produce red wine.

Silver nitrate is an allowed wine additive in New Zealand and a few European countries where it is used to suppress mercaptans and other nasty sulphurous wine odours. AWBC General Manager Sam Tolley said, “The level of silver detected…did not represent a risk to public health.” In contrast to Mr Tolley’s confident assurance my research indicates that silver nitrate is a known toxic and corrosive chemical which, according to the Columbia Encyclopedia, can possibly cause “growth abnormalities or genetic modifications…mutations in DNA and living cells…and tumours.” Mr Tolley said the allegations, concerning the addition of tannin to change the colour of white grape juice, were also investigated but were not substantiated.

Given that this case only came to light through the efforts of a couple of whistleblowers, consumers may well wonder at the quality and efficacy of Australia’s wine regulatory system. Meanwhile the spin doctors at Kingston Estate are no doubt pondering the appropriateness of their latest advertising campaign which features the slogan, “Red without rules.” Pending the AWBC investigation two large retail chains in the UK, Tesco and Waitrose, withdrew Kingston Estate wines from their shelves. Whatever the outcome of legal proceedings the reports will inevitably have a disastrous effect on Kingston Estate’s local and international markets. And even the hint of a wine scandal clearly has the potential to tarnish Australia’s standing as an exporter of top quality wine to the world.

© Martin Field