WSA cork taint survey under fire
- Friday 11 October 2002
Doubts about the soundness of the methodology in the UK Wine and Spirits Association's 18-month survey 'Musty flavour defects in wine in the UK' led major drinks chain Oddbins to pull out early on, and the Australian Wine Research Institute has condemned the findings as unsound.
The WSA – along with a consortium of cork manufacturers, food and wine distributors, supermarkets, synthetic stopper manufacturers, bottlers and distillers, and the Campden and Chorleywood Food Research Association – tested 13,780 bottles for mustiness.
It found that between 0.7% and 1.2% of bottles had cork taint – a statistic widely derided by the wine industry, which has long accepted the figure to be above 5%.
Journalist Jamie Goode argues in Harpers that the survey – published in June this year – had major flaws.
Wines initially considered 'musty' by a team of professional assessors were resealed and sent for verification to one of two independent companies.
It was the fact the wines might have waited a week before being retasted that renders the survey unsound. Of the 277 samples sent for verification, only 34% were verified musty. 'This is a staggering discrepancy,' the magazine says.
AWRI scientist Peter Godden said there were two holes in the methodology. The first assumption – that TCA (cork taint) is stable enough to be detectable a week after opening the bottle – is wrong. Godden said it was 'quite probable' that most of the TCA would have been absorbed back into the cork.
Godden also said it is often impossible to detect musty off-flavours if the wine is oxidised. In tests carried out as part of an insurance investigation, the AWRI found, 'oxidation has a massive effect on the ability of experienced tasters to assess TCA.'
WSA director Quentin Rappoport told decanter.com the argument boiled down to disagreement between two sets of scientists. He said the Campden and Chorleywood Food Research Association believed TCA could not be absorbed back into the cork, and also that TCA could be detected over oxidation.
'I hope the CCFRA and the AWRI can get together and solve it,' he said.
Rappoport also pointed out that the initial figure, before sending the bottles for verification, was 2% mustiness.
'That is still a lot lower than most people quote.'