Wine Authenticity (World of Forensic Science)
Counterfeiting of wine has occurred for centuries, but since the 1990s both rumors of counterfeit wines and cases of fraud associated with wine increased drastically. Some believe that wine counterfeiting is a multi-million dollar industry associated with organized crime. Both the FBI and Scotland Yard have investigated cases of crime fraud. Industry experts estimate that about 5% of all wine sold is counterfeited.
A variety of testing methods can be used to ensure the authenticity of wine. Along with more traditional methods of inspection, chemical assays such as stable isotope analysis, chromatography, mineral content analysis, and DNA fingerprinting are being used by various wineries. A novel method that incorporates unique DNA codes into the label of wine bottles is also used to avoid counterfeiting.
Wine fraud occurs in many different forms. Often counterfeiters target the more expensive and older wines. Not only are sales of these wines financially profitable, but few people are familiar with the labels and other markings on these bottles so the fraud is harder to detect. Auctioneers and resellers sell expensive wines in large quantities, so the contents of a bottle or a case can be tampered with without anyone noticing for some time. One of the easiest scams involves replacing the contents of a case of expensive wine with bottles of less expensive wine. The cases are sold at auction houses without ever being opened and then stored for years in warehouses before being sold again. By the time someone decides to verify the contents, the counterfeiter is removed from the crime by both time and by layers of transaction.
Another common type of fraud involves replacing the contents of an expensive bottle of wine with a wine of a lesser quality. Using a two-pronged wine opener, corks can be removed and replaced with little damage. Capsules, which are the metal or plastic coverings sealing the corks in the bottle, can also be replicated and replaced. Recipes for duplicating expensive wines using inexpensive ingredients are known to experienced sommeliers (wine stewards) as well as counterfeiters. For example, blending a 1960 Pétrus with a Pomerol can mimic a 1961 Pétrus, which is one of the most expensive wines sold and usually costs more than ten times as much as the 1960. Other types of altering the contents of a wine bottle include adding sugar or other flavorings, and watering down the contents.
Blending was at the heart of a series of scandals in the Burgundy region of France in 2001. Several chateaux (vineyards) were blending burgundies with table wines from other regions of France, which is illegal. The winemakers involved confessed to making more than 10,000 cases of fraudulent wine during a ten-year period. Some of the wine was sold for as much as 300% profit.
Relabeling bottles of a less expensive wine with labels of a more expensive vintage is another common scam. In 2002 customs agents in China seized approximately 700 bottles of a wine that usually sells for $200 that had been relabeled as 1982 Chateau Lafite Rothschild, which sells for more than $5,700. The gang of counterfeiters had been selling the bottles for approximately $1,100 each.
In 1998 a wine auctioneer in Australia noticed that the bar code on some bottles of 1990 Penfolds Grange on the auction block were printed in black while genuine bottles have the code printed in red. Further investigation revealed that the labels had been forged and there were at least ten discrepancies between the original and the fake. One of the discrepancies included the misspelling of the word "pour" for "poor." Penfolds Grange 1990 is one of Australia's top wines and was named Wine of the Year by The Wine Spectator magazine in 1995. In 2005 it sells for more than $400 a bottle.
In 2000 a large wine fraud ring was broken up in Tuscany. More than 20,000 bottles of fake Tenuta San Guido 1994 and 1995 Sassicaia were discovered. Sassicaia is one of Italy's top wine producers known for its Super Tuscan. When the storage cellars of the gang were raided, another six million bottles of fake Chianti were seized. The police were alerted when a customer became suspicious that the price for the wine was too low. The counterfeiters tried to convince the customer that the original sale of the wine had fallen through and so they needed to sell it at a special price. Twelve people were arrested in connection with the incident.
A variety of techniques are used to determine the authenticity of wine. Traditional techniques involve careful observation of the bottle, its labels and its contents. This requires familiarity with both the wine and experience detecting counterfeits. Novel techniques of authentication rely on biochemical methods including stable isotope analysis, chromatography, mineral content analysis, and DNA fingerprinting.
General observation of the parts of the wine bottle and experience with wines are fundamental to the detection of counterfeit wines. The type of glass used to make the bottle should be consistent with the time period. Glass making has changed throughout the years and the type and manufacture of glass used should reflect these changes. The capsule should be consistent in color and markings with other examples from the same vintage. The corks should also be inspected. Since 1970, corks have been printed with the correct vintage and brand. Prior to 1970, casks were often shipped to resellers, who corked bottles themselves, so they may have printed their own corks. Labels may show damage such as peeling and staining, especially in older wines stored in the proper humid conditions. When old wines have labels in perfect condition, it may be a sign of relabeling. Spelling errors and font changes are key indicators of fraud. Wines that are imported into the United States have strip labels that show the name of the importer. These should also be consistent with the wine.
As grapes grow, they incorporate atoms of hydrogen, carbon, nitrogen and oxygen from their environment into proteins and carbohydrates. Each of these elements exists in more than one form called stable isotopes. Stable isotopes have the same number of protons and electrons but different numbers of neutrons. For example, carbon has two stable isotopes: one of them has 12 neutrons in the nucleus and the other has 13. The stable isotopes of carbon are referred to as 12C and 13C, respectively. About 98.9% of all carbon is 12C, while 1.1% is 13C, however these ratios change depending on geographic region and weather conditions. Nuclear magnetic resonance (NMR) is used to measure the stable isotope ratios of hydrogen in the alcohol of wines. Isotopic ratio mass spectrometry (IRMS) is used to measure the stable isotope ratios of carbon and oxygen.
Grapes grown in different regions during different years have different ratios of stable isotopes and these ratios remain constant when the grapes are processed into wine. The European Union houses a database containing the stable isotope ratios from all of its wine growing regions measured each year. Determination of stable isotope ratios from a bottle of wine can be compared to the values in the database in order to determine the origin of the grapes used to make the wine.
Chromatography is a technique that involves separating the components of a mixture, such as wine. An extremely sensitive form of chromatography, high-pressure liquid chromatography (HPLC) can measure the relative quantities of the pigments, called anthocyanins, which give wine its red color. The ratio of two particular forms of anthocyanin is often used as an indicator of the type of grape used to make the wine. Evidence shows that the ratio of these two forms of anthocyanin is determined by the genetic composition of the grapes and therefore indicates the type of grape used to make the wine. However, some chemists believe that concentrations of anthocyanin in wine are affected by processing. They have found that length of fermentation, exposure to varying temperatures and the addition of enzymes, can affect the anthocyanin ratios.
When grapes grow, they incorporate small amounts of metals from the soil into their skin and pulp. These metals are called trace metals and they include aluminum, calcium, copper, iron, potassium, magnesium, strontium, and zinc, among others. The concentration of these metals varies from location to
In 2004 researchers from the University of Seville, Spain, developed a method to identify the trace metal composition of sparkling wines. They used atomic spectrophotometers to determine the elemental composition of the wine based on patterns of absorption of electromagnetic waves. Samples of cava from Spain and champagne from France were compared. The two wines are made using identical processes, but the regions from which the grapes originate differ. As a result, the trace mineral content also differs. For example, the ratio of strontium to zinc was always greater than 1 in cava and always less than 1 in champagne. The researchers showed that using the concentrations of 16 different trace minerals, they could identify the regional identity of the wine with perfect accuracy.
In the late 1990s a group of researchers from the University of California, Davis, developed a method to identify wine-grapes based on their genetic characteristics. They identified 17 different regions of DNA that varied greatly between different grape varieties. Collaborating with a research team from Montpellier, France, they assembled a database of genetic profiles for 300 different wine-grape varieties. In 2005, the database was expanded to include the more than 2,500 varieties of wine-grapes in existence.
Beginning in 2005 the research group in Montpellier began developing methods to perform DNA fingerprinting on wine. Using techniques similar to those used to study DNA from mummies, they believe that they will be able to extract and purify enough DNA from wine to compare it to the database of grape-wine genetic markers. Some scientists are skeptical of the technique however. Wine-grapes are heavily processed during the wine making process and the DNA may be too damaged to analyze.
In 2001 an Australian wine company, BRL Hardy, began labeling their wine with ink laced with DNA as a security measure against tampering. The technology was developed by a company called DNA Technologies for use in labeling souvenirs from the 2000 Sydney Olympics. DNA Technologies extracted DNA from one of BRL Hardy's 125-year-old grape vines. A segment of the vine DNA is then coated with a protective protein and imbedded into the neck label of the wine. Along with the DNA, optical taggants that emit unique spectral signatures in the presence of the proper excitation wavelengths are incorporated into the label. A handheld electronic scanner can then be used to test for the presence of the DNA label. BRL Hardy believes that the technology will discourage counterfeiting of its wines.
SEE ALSO Analytical instrumentation; DNA fingerprint; DNA sequences, unique; Fluorescence; Soils.