By Jason Clevenger
Summary: A group of Australian researchers attempted to measure the amount of gluten protein in beer using several testing methods. More than 60 types of beer, including those made with wheat and barley and those made with gluten-free grains, were included in the study. They were tested with the traditional ELISA R5 antibody assay and a newer technology called mass spectrometry.
Lagers, ales and stouts, including several that claimed to have no or very low — less than 20 parts per million of gluten were tested. The ELISA test found that roughly half contained more than 20 ppm of gluten, with eight having more than 10,000 ppm. However, the mass spectrometry tests found that only 12 had detectable levels of wheat gluten. Beers labeled gluten free and made from gluten-free rice and sorghum had no detectable gluten when tested by either method.
Conclusion: Conflicting results from these two analytical methods suggest that accurate, rapid measurement of gluten levels in common foods still remains a technical challenge. Tests can be accurate or fast, but not necessarily both. Beer is particularly difficult to test since it typically contains protein fragments from several varieties of wheat. The authors suggest that the ELISA test tends to over-report the presence of gluten in beer, and that the mass spectrometry technique is more sensitive and reliable. Those looking for a gluten-free beer should take comfort from the fact that beers with a gluten-free label do contain less than 20 ppm of gluten, an amount widely considered safe.
 “Measuring hordein (gluten) in beer – a comparison of ELISA and mass spectrometry.”, Tanner GJ, Colgrave ML, Blundell MJ, Goswami HP, Howitt CA, #PLoS One# 2013; 8(2):e56452.