Journal of Analytical Toxicology 2015;39:160 doi:10.1093/jat/bku122 Advance Access publication October 22, 2014
Letter to the Editor
When Is a Beer Not a Beer: Iso-a-Acids Not Necessarily Proof of Ethanol Consumption? Alcohol congeners are compounds found in alcoholic beverages that may allow the identification of the type of alcoholic beverage that has been consumed (1). Recently, it has been suggested that iso-a-acids (biomarkers that are derived from the hop plant) may be able to be used to detect the consumption of beer and by inference alcohol. Iso-a-acids are formed either during the boiling phase of beer production or by conversion outside the brewery, all of these are derived from the alpha acids found in hops (2). Iso-a-acids are only formed or used during the brewing process, which uses 97% of the global hop crop (3), and are therefore unlikely to be found in the body following the administration or consumption of hops in other forms (such as tea like infusions). This would make iso-a-acids a unique biomarker for beer consumption. A study in which human subjects consumed beers containing ‘low’ defined in the paper as 10 IBU (International Bitterness Units) and ‘high’ (40 IBU) levels of iso-a-acids proved that iso-a-acids could be detected in the blood for up to 6 h and further confirmed the use of iso-a-acids as a confirmation of the consumption of beer (4). Unfortunately, the detection of iso-a-acids may not prove that any alcohol consumed was from beer. Non-alcoholic beers (generally defined as beers containing ,0.5% ABV) are becoming increasingly popular around the world especially in Western Europe, Australia and the Middle East (5). Non- and low alcoholic beers can be produced by postfermentation dealcoholization or biological (during fermentation) methods, all of which may include the use of hops during production. Only dealcoholization using reverse osmosis has been found to result in a large reduction in the bitterness levels (6). Thus non-alcoholic beers can contain a range of iso-a-acid concentrations; in fact Nanny State (Brew Dog, UK) with an alcohol content of 0.5% ABV claimed a bitterness content of 45 IBU, and based on the previous study (4), would be likely to have a similar iso-a-acids pharmacokinetic profile to that of alcoholic beer. Further work will hopefully enable the distinction between the alcohol congeners in alcoholic and non-alcoholic beers but at the present time Forensic Toxicologist’s should be aware
that the presence of iso-a-acids in blood does not necessarily confirm the alcoholic beverage that may have been consumed and non-alcoholic beers may even be used to mask the alcoholic beverage consumed.
References 1. Rodda, L.N., Beyer, J., Gerostamoulos, D., Drummer, O.H. (2013) Alcohol congener analysis and the source of alcohol: a review. Forensic Science, Medicine, and Pathology, 9, 194–207. 2. Roberts, T.R., Wilson, R.J.H. (2006) Hops. In Priest, F.G., Stewart, G.G. (eds), Handbook of Brewing, 2nd edition, Taylor & Francis Group, Boca Raton, pp. 177– 280. 3. Scho¨nberger, C., Kostelecky, T. (2011) 125th anniversary review: the role of hops in brewing. Journal of the Institute of Brewing, 117, 259– 266. 4. Rodda, L.N., Gerostamoulos, D., Drummer, O.H. (2014) Pharmacokinetics of iso-a-acids in volunteers following the consumption of beer. Journal of Analytical Toxicology, 38, 354–359. 5. Euromonitor International (2013-2014). Beer Market Research Reports. http://www.euromonitor.com/beer (accessed Aug 11, 2014). 6. Bra´nyik, T., Silva, D.P., Baszczynski, M., Lehnert, R., Almeida e Silva, J.B. (2012) Review: a review of methods of low alcohol and alcohol-free beer production. Journal of Food Engineering, 108, 493– 506.
Peter D. Maskell1,*, Paul S. Hughes2 and Dawn L. Maskell3 1 Department of Chemical and Forensic Sciences, University of Huddersfield, Huddersfield, UK 2 School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, UK 3 Institute of Biological Chemistry, Biophysics, and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh, UK *Author to whom correspondence should be addressed. Email: [email protected]
# The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected]
Letter to the Editor
When Is a Beer Not a Beer: Iso-a-Acids Not Necessarily Proof of Ethanol Consumption? Alcohol congeners are compounds found in alcoholic beverages that may allow the identification of the type of alcoholic beverage that has been consumed (1). Recently, it has been suggested that iso-a-acids (biomarkers that are derived from the hop plant) may be able to be used to detect the consumption of beer and by inference alcohol. Iso-a-acids are formed either during the boiling phase of beer production or by conversion outside the brewery, all of these are derived from the alpha acids found in hops (2). Iso-a-acids are only formed or used during the brewing process, which uses 97% of the global hop crop (3), and are therefore unlikely to be found in the body following the administration or consumption of hops in other forms (such as tea like infusions). This would make iso-a-acids a unique biomarker for beer consumption. A study in which human subjects consumed beers containing ‘low’ defined in the paper as 10 IBU (International Bitterness Units) and ‘high’ (40 IBU) levels of iso-a-acids proved that iso-a-acids could be detected in the blood for up to 6 h and further confirmed the use of iso-a-acids as a confirmation of the consumption of beer (4). Unfortunately, the detection of iso-a-acids may not prove that any alcohol consumed was from beer. Non-alcoholic beers (generally defined as beers containing ,0.5% ABV) are becoming increasingly popular around the world especially in Western Europe, Australia and the Middle East (5). Non- and low alcoholic beers can be produced by postfermentation dealcoholization or biological (during fermentation) methods, all of which may include the use of hops during production. Only dealcoholization using reverse osmosis has been found to result in a large reduction in the bitterness levels (6). Thus non-alcoholic beers can contain a range of iso-a-acid concentrations; in fact Nanny State (Brew Dog, UK) with an alcohol content of 0.5% ABV claimed a bitterness content of 45 IBU, and based on the previous study (4), would be likely to have a similar iso-a-acids pharmacokinetic profile to that of alcoholic beer. Further work will hopefully enable the distinction between the alcohol congeners in alcoholic and non-alcoholic beers but at the present time Forensic Toxicologist’s should be aware
that the presence of iso-a-acids in blood does not necessarily confirm the alcoholic beverage that may have been consumed and non-alcoholic beers may even be used to mask the alcoholic beverage consumed.
References 1. Rodda, L.N., Beyer, J., Gerostamoulos, D., Drummer, O.H. (2013) Alcohol congener analysis and the source of alcohol: a review. Forensic Science, Medicine, and Pathology, 9, 194–207. 2. Roberts, T.R., Wilson, R.J.H. (2006) Hops. In Priest, F.G., Stewart, G.G. (eds), Handbook of Brewing, 2nd edition, Taylor & Francis Group, Boca Raton, pp. 177– 280. 3. Scho¨nberger, C., Kostelecky, T. (2011) 125th anniversary review: the role of hops in brewing. Journal of the Institute of Brewing, 117, 259– 266. 4. Rodda, L.N., Gerostamoulos, D., Drummer, O.H. (2014) Pharmacokinetics of iso-a-acids in volunteers following the consumption of beer. Journal of Analytical Toxicology, 38, 354–359. 5. Euromonitor International (2013-2014). Beer Market Research Reports. http://www.euromonitor.com/beer (accessed Aug 11, 2014). 6. Bra´nyik, T., Silva, D.P., Baszczynski, M., Lehnert, R., Almeida e Silva, J.B. (2012) Review: a review of methods of low alcohol and alcohol-free beer production. Journal of Food Engineering, 108, 493– 506.
Peter D. Maskell1,*, Paul S. Hughes2 and Dawn L. Maskell3 1 Department of Chemical and Forensic Sciences, University of Huddersfield, Huddersfield, UK 2 School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, UK 3 Institute of Biological Chemistry, Biophysics, and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh, UK *Author to whom correspondence should be addressed. Email: [email protected]
# The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected]
