Shedding Light on Wine Fraud With NMR Fingerprinting

Wine forgery takes place on a global scale, but is on the rise in central Europe. Higher value varieties, originating from key wine producing countries such as France, Italy, Spain, Austria, Germany and Chile, are at a higher risk of wine fraud and forgery, but any country or variety could be threatened. A recent report investigating 743 wine importers, distributors and retailers, as well as cafés, hotels and restaurants, found that in 2016 and 2017, 22% and 15% of the establishments misrepresented wine origins in some form [1].

What is wine fraud?

‘Wine fraud’, as a broad term, encompasses a number of methods of deception, including adulteration, counterfeiting (e.g. mislabeling/misrepresentation) and intellectual property infringement. It can be broadly categorized into fraudulent wine selling and fraudulent wine production. In the case of the former, wine counterfeiting involves the misrepresentation and mislabeling of grape variety, blend origin or vintage, often to pass off a cheaper product as a more expensive variety. Wine adulteration during production usually involves the use of additives, such as coloring agents and flavorings, to add desirable characteristics to the wine where they are lacking. The goal of this is usually to market a cheaper product at premium prices, which affects the quality of the product.

Tools for detecting adulteration

The accuracy and reliability of wine fraud detection depends on the method’s degree of sophistication. Crude methods, such as inspecting the label and seal for authenticity by eye, are more subject to variation. Bubble seals and DNA tags are more objective approaches and are often used to combat wine fraud, by tracking wines and adding an extra layer of authenticity. Traditional methods of inspection, such as chemical assays (stable isotope analysis), chromatography, mineral content analysis and DNA fingerprinting are making way for more quantitative, rapid and reliable methods for wine profiling, like nuclear magnetic resonance (NMR) spectroscopy.

NMR screening has advanced capabilities beyond those of conventional analytical methods, which are not capable of generating the same breadth of parameters with minimal sample runs and preparation times. Instruments acquire spectroscopic profiles – or fingerprints – from wine samples, and compare them to a large database of authentic wine samples, using a multivariate statistical approach. This provides information that is both targeted (quantification of defined substances) and non-targeted (identifying deviations from reference spectra), ranging from the detailed chemical composition of the wines and the geographical origin (including soil influence), as well as wine variety, vintage year and any form of adulteration. NMR analysis provides the wine producer with a detailed certificate with 52 different measurement parameters, including testing for decomposition, markers of fermentation, amino acids, phenol derivatives and stabilizing agents.

Testing country of origin

Wine obtains much of its commercial value from the geography and vintage of the grape. A large amount of resources have been channeled into developing technology that can verify these features. Geographic information systems (GIS) are an example of this, used to map wine oxygen stable isotope ratios to obtain unique geographical information, based on a predicted precipitation map. Technologies such as this have enabled analysts to determine a wine sample’s country of origin [2].

NMR spectroscopy provides high-throughput screening of wine for multiple forms of adulteration, including point of origin. NMR has a high level of reproducibility, which enables powerful statistical analysis to detect minute changes across multiple parameters at a time. This directly facilitates the determination of geographical origin, on a country-wide basis as well as down to sub-areas within a country. 

The impact on exports

Wine adulteration has a worldwide impact on producers and traders. It is vital for wine producers to maintain consumer trust in the marketplace by safeguarding their product against fraud and guaranteeing international authenticity. A negative impact on exports could have devastating consequences for the economy of a wine producing country. Many producers may not yet be aware of the benefits of sending samples of their wine to a testing laboratory for NMR analysis, but doing so and obtaining a certificate of authenticity will allow them to confidently market their wine to retailers and traders across the globe.

It’s not only wine producers who are at risk of wine fraud. Fine wine collectors invest in bottles that can cost thousands of pounds/dollars, so have a lot to lose from a fraudulent product. Previously, authentication methods required the bottle of wine to be opened for analysis, which greatly devalues the product. Modern techniques, including NMR, leave the bottle intact and are non-invasive, which is a huge benefit to the industry. The conviction of Rudy Kurniawan in 2014 for mass scale wine fraud is a key example of a recent case of high-profile wine fraud. He bought cheaper bottles of wine and counterfeited the labels and seals to alter the vintage, then sold them for millions of dollars at auction [3]. Cases such as this will impact consumer trust in manufacturers, especially traders in fine wine where large sums of money are at stake.

The ongoing fight with fraud

Countries around the globe are now contributing to an international wine database, which compares the metabolic profiles of wines with a large database of authentic samples obtained using high-throughput NMR. Wine producers can contribute to this database, supporting the fight against wine fraud, and at the same time acquire a certificate of authenticity for their wine. The more countries that contribute to the international database, the stronger the comparisons will be.

References

1. Directorate-General for Competition, Consumer Affairs and Fraud Control (DGCCRF), Control of foreign wines without a geographical indication (VSIG), July 2018. https://www.economie.gouv.fr/dgccrf/controle-des-vins-etrangers-sans-indication-geographique-vsig [Accessed 09/11/18].

2. West JB., Ehleringer JR. and Cerling TE. (2007) Geography and Vintage Predicted by a Novel GIS Model of Wine δ18O, Journal of Agricultural and Food Chemistry, 55, pp: 7075-7083.

3. The great wine fraud, The Guardian, Sept 2016, https://www.theguardian.com/global/2016/sep/11/the-great-wine-fraud-a-vintage-swindle [Accessed 29/10/18].