Updated October 2022 by Dante Moroni
The gluten content of traditional barley beer significantly drops during the brewing process. This can be the result of various factors such as: endogenous barley malt enzymes, yeast metabolism, filtration technologies, protein precipitation, and sometimes exogenous enzyme additions (AN-PEP/Papapin). This had me wondering about the gluten content of regular barley beers. I decided to do some of my own beer in gluten research.
The test kit I use is EZ Gluten. It is a reliable at home gluten test that can measure down to 10ppm. The test is based on the Skerritt antibody which is great at picking up D-hordein, the main gluten protein in beer. However, the results are still only qualitative. I believe other blogs using lateral flow device gluten test kits are less sensitive than EZ gluten and prone to false negatives due to the lack of an overflow/hook lane and the use of antibodies not specific for D-hordein.*
I wanted to add to the available data and generate a conclusion on the level of gluten in several common beers. I’ve devised a prototype system for deciphering an estimated concentration from the test strips. I’ve also factored in any available R5 competitive results, though only 3 of the beers have those available.*
Barley Beer Results
The main theory I have for the inconsistent results from some of these beers are the different levels endogenous barley peptidase enzymes getting activated during barley germination.9 Or related to that, potential wheat contamination in barley harvests depending on which crops are being rotated and other sources of cross contamination. This is what is seen with oat production and why oats need to be certified gluten free.3 These contaminating wheat grains may not germinate as readily as barley and their enzymatic activity may be low during malting.4 Also, variations in brewing conditions as well as variations in exogenous enzyme acitivty (Papain/AN-PEP) may play a role.
Traditional barley beer often has gluten concentration higher than 10ppm. However, there are a small percentage whose gluten levels seem to be below 10ppm. This is likely due to some proprietary processing technique, like enzyme addition (AN-PEP/Papain), protein precipitation, filtration, unique yeast strains, and or high protease activity barley malt. Those beers would be Duvel Golden Ale, Duvel Tripel Citra Hop, and Bud Light NEXT.
Disclaimer: This content is non peer reviewed and should not be used in any way as medical advice.
- Allred LK, Park ES. EZ Gluten for the Qualitative Detection of Gluten in Foods, Beverages, and Environmental Surfaces. Journal of AOAC International. 2012;95:1106-17.
- Koerner TB, Cleroux C, Pourier C, Cantin I, Alimkulov A, Elamparo H. Gluten Contamination in the Canadian Commercial Oat Supply. Food Additives and Contaminants. 2011;28:705-710.
- Pre-Harvest Sprouting in Wheat and Barley. Birchip Cropping Group. 2014
- Konig J, Holster S, Bruins M, Brummer R. Randomized Clinical Trial: Effective Gluten Degradation by Aspergillus niger-derived Enzyme in a Complex Meal Setting. Nature Research, Scientific Reports. 2017;7:13100.
- Salden B, Monserrat V, Troost F, Bruins M, Edens L, Bartholome R, Haenen G, Winkens B, Koning F, Masclee A. Randomised Clinical Study: Aspergillus niger-derived Enzyme Digests Gluten in the Stomach of Healthy Volunteers. Alimentary Pharmacology and Therapeutics. 2015;42:373-85.
- Tack G, Water J, Bruins M, Kooy E, Bergen J, Bonnet P, Vreugdenhil A, Korponay I, Edens L, Blomberg B, Schrueurs M, Mulder C, Koning F. Consumption of Gluten with Gluten-Degrading Enzyme by Celiac Patients: a Pilot-Study. World Journal of Gastroenterology. 2013;19:5837.
- Clinical Trials Website: AN-PEP
- Kerpes R, Knorr V, Procopio S, Koehler P, Becker T. Gluten-Specific Peptidase Activity of Barley as Affected by Germination and Its Impact on Gluten Degradation. Journal of Cereal Science. 2016;68:93-99.
- Swedish Beer Testing Study Ridascreen R5 Competitive Results
- Scricciolo A, Lombardo V, Elli L, Bascunan K, Doneda L, Rinaldi F, Pinto D, Araya M, Costantino A, Vecchi M, Roncoroni L. Use of a Proline Specific Endopeptidase to Reintroduce Gluten in Patients with Non-Celiac Gluten Sensitivity: A Randomized Trial. Clinical Nutrition. 2022;41:2025-30.