Global beer production in 2014 was a staggering 1.93 billion hectoliters, with a growing interest in specialty craft beers and international trade increasing in high value bottled beers. As consumers are clearly prepared to pay a significant premium for foreign beers with internationally recognized brand names, how can they be sure they are getting the ‘authentic’ product?
Compared to the large number of studies on wine authenticity, beer authenticity has been somewhat neglected, despite the risks of fraudulent substitution of inferior beer sold as a premium product. In a 2016 study published in the journal Food Control, a total of 80 bottled beers from 27 countries were purchased from supermarkets in South Korea and assigned to groups covering four geographical areas – North and South America, Asia, EU and Australia/New Zealand. Carbon isotope ratios (13C/12C) were measured by stable isotope ratio mass spectrometry combined with a GasBench II, whilst multi-element and strontium isotope analyses (87Sr/86Sr) were carried out by Inductively Coupled Plasma Mass Spectrometry using a multi-collector.
Authenticity of Beers
Average δ13CDIC values ranging from -26.74‰ to -19.94‰ indicated that beers were predominantly produced from barley or wheat because C3 plants are known to have δ13C values that range from -33 to -24‰. However, some beers had higher δ13C values, suggesting that either corn or rice, or inexpensive, C4-derived sugars had been used as a substitute for cereal crops. Average δ18O values for beers from geographical regions were different, reflecting a correlation between latitude and water isotopic composition. The origin of the water used in brewing, whether from carbonate or silicate rock regions of the world, was also reflected in 87Sr/86Sr ratios. As with other work on authenticity, it was necessary to apply multi-variate analysis to these complex isotopic datasets where a clear discrimination could be obtained between beers of different geographical origins. This means that, for example, a beer produced locally in Asia and labeled as European could easily be distinguished as fraudulent.
Other approaches are also being used to verify the authenticity of beers, for example using different spectroscopic techniques including near infra-red spectroscopy. In a paper published in the journal Analytica Chimica Acta it was shown using spectroscopy that it was possible to fingerprint Italian high-value craft beer and differentiate it from other competing or lower quality products. Although no single spectroscopic fingerprint could be used to distinguish these beers, with a data fusion technique and then application of appropriate chemometric methods, differentiation was possible.
These analytical techniques are fairly sophisticated, whether they are using isotopic or spectroscopic measurement. However, these methods do enable direct analysis of the beers requiring only degassing. This means that large numbers of samples can be quickly analyzed and the way is open for the authorities to conduct routine checking of beers from the market.
Looking back at historical records it is interesting to reflect on how far we have moved from detection of crude adulteration of beer, for example, with picric acid or sulfuric acid as reported in public health papers and records published in the year 1884 to the sophisticated testing of today.
Nowadays, we can obtain a unique fingerprint of a beer sample and generate isotopic signatures giving clear indications of plant sources of ingredients and geographical origin of the water used for brewing.