Fermented grape juice, commonly referred to as wine, is highly regarded by many societies. The production of wine, including what can be added, is tightly controlled in many regions because geographical origin is one of the defining characteristics consumers traditionally look for when buying a bottle.
Until recently there has been little global harmonization of standards. The International Organization of Vine and Wine (OIV) and other bodies have now begun to push for greater coordination, but there are still regional differences about what can and cannot be added to wine.
Because geographical origin is so important to wine buyers, and some regions command a premium price, criminals are encouraged to initiate fraud, which can take several forms, including mislabeling, blending and adulteration. In 2016 and 2017, an investigation into 743 wine importers, distributors, retailers, and hospitality establishments found 22% and 15% of firms held wines where the contents were misrepresented on the label.
Ensuring of the authenticity of wine and other alcoholic beverages is therefore very important for businesses wishing to avoid financial repercussions, loss of reputation, and legal censure.
Types of Wine Adulteration
Perhaps the oldest form of adulteration is dilution with water. Once a common practice, this is now considered to be fraud, but it is still done for two reasons:
- To reduce high alcohol content below a threshold value to avoid high duties and taxes
- To increase volume
Sugar may be added to unfermented grape must (chaptalization) to create a higher alcohol content, and thereby higher valued wines. In addition, wines with low alcohol levels may be unstable, so adding sugar before fermentation can be vital for the vintage. This process is legal in some regions and vintages, for example if there has been minimal sun during the grape-ripening period. Most wine-producing regions, however, ban chaptalization. It is also completely illegal to add raw alcohol to wine for the same purposes and wine-producers should not add sugar to dry wines to make them sweeter (producing sweet wine is more expensive).
Glycerol is sometimes fraudulently added to wine to disguise poor quality. After water and ethanol, glycerol is the abundant compound in wine. It contributes to mouthfeel properties and smoothness because it is colorless, odorless and has little noticeable flavor but is syrupy.
Acidity is important in wine. At sufficient levels it helps with aging, stability and the organoleptic properties of the final product. L-tartaric acid is the main organic acid responsible for acidity in wine, but this is generally lower in more mature grapes, which may therefore require acidification during production. L-tartaric acid is a natural byproduct of the wine industry, but it can also be made from fossil fuels and extracted from certain plants. The International Wine Code does regulate the use of L-tartaric acid, stating only that which is sourced from grapes can be used.
Finally, bubbles are obviously a major component of sparkling wines. Traditionally, the bubbles are created during a second fermentation in the bottle or tank. The CO2 in the bottle therefore reflects the botanical origin of the sugars from which the gas originated. Carbonation by direct injection of ‘food grade’ CO2 is possible, but EU legislation forbids the use of any exogenous carbonic anhydride in semi-sparkling and sparkling quality wines.
The authenticity of a wine can be ascertained using stable isotope ratio analysis, looking at different substances. For example, when looking for adulteration by meteoric-(tap)-water, the laboratory can look at the water oxygen isotopes (18O/16O). The principle is that the 18O/16O is higher in fruit (grape) water, although, because of natural geographical variations, it is necessary to use an internal parameter for correlation, such as the alcohol 18O/16O.
To detect added sugar or ethanol, the testing facility will look for the isotope ratios of the compounds carbon (13C/12C) and hydrogen ((D/H)I, (D/H)II). Different plants have different ratios, which will then allow the detection of sugars derived from cane, beet, corn syrup, etc., and added ethanol.
The addition of glycerol is detected by looking at its carbon isotopes (13C/12C). Naturally wine-derived glycerol differs significantly from the much cheaper synthetic alternative. Glycerol from other sources (e.g. plant sources) can be detected by using the carbon isotope composition of ethanol as an internal parameter for comparison.
To detect the source of tartaric acid, testing laboratories use multi-isotope fingerprinting (13C/12C, 18O/16O, 2H/H) of the tartaric acid present in wine. The principle is that the multi-isotope fingerprint of tartaric acid from grapes differs significantly from synthetic tartaric acid and other plant-derived forms.
Finally, the source of carbon dioxide in sparkling wine can be identified using carbon (13C/12C) stable isotope ratio analysis of the CO2 in the wine. Scientists will look to see if the carbon isotope ratio of CO2 in the bottle reflects the botanical origins of the wine. CO2 derived for alternative sources and then injected into the wine will differ greatly.
The same principles used in isotope analysis can also be utilized to establish geographical origin. The European Union (EU) has created a database for monitoring, amongst other things, geographical origin for certain countries. Stable isotope ratio analysis is used to create a multi-isotope fingerprint (18O/16O, 2H/H, 13C/12C), indicative of the characteristics of the region of wine production. If the wine inside the bottle differs from that which is advertised on the outside, with reference to the reference dataset, it is clearly a case of fraud.
Other Alcoholic Drinks
The potential gains made by fraudsters with wine are also seen in other alcoholic beverages. The EU’s Intellectual Property Office has estimated counterfeit spirits cost the European economy €2.8 billion and, in just one year, Interpol and Europol seized 26.4 million liters of counterfeit alcohol, estimated at €230 million. In February 2018, Mexican police seized 20,000 gallons of black-market tequila, with over 200 gallons containing dangerous levels of methanol, destined for resorts catering to North American tourists.
Fraudsters are attracted by the ability to use cheaper raw ingredients and practices to replicate products that sell for a premium price. As with sparkling wines, the addition of carbon dioxide or sugar to ciders, perries and hydromels in the EU means they cannot be considered genuine and will not command the premium price. In the US, carbonation is allowed.
As with wine, stable isotope ratio analysis can be used to verify the authenticity of a product. The source material of the alcohol, natural carbonation and provenance, can all be verified by looking at particular compounds. Applications include (product, compound, detection):
- Beer: CO2 – industrial CO2, also for alcohol free beers
- Beer: ethanol – source material of the alcohol
- Ciders: ethanol – added sugar and CO2
- Tequila: ethanol – verify blue agave as botanical origin
- Rum: ethanol – verify sugarcane as botanical origin
- Vodka: ethanol – addition of alcohol from sugarcane or corn
Stable Isotope Ratio Analysis
SGS offers a comprehensive range of services to help alcoholic beverage manufacturers and suppliers ensure their products match the description on the label. Using stable isotope ratio analysis, their experts can help identify counterfeit products, detailing the form of the corruption.
Food Fraud Surveillance
SGS Digicomply offers a dedicated database to global food fraud surveillance. This platform is constantly updating and aggregating facts from the most relevant sources, such as trade associations, governments, media and scientific institutions. Knowing your materials, ingredients and their associated risks is an essential part of the vulnerability assessment as prescribed by food safety certification schemes.
For the complete range of SGS services and support visit SGS Food Safety.