Gluten-free barley malt beers

Abstract

About 75% of the barley proteins are gluten, with 50% prolamins and 25% glutenins. Gluten is related to gluten allergy and celiac disease. Malting and brewing processes removes much of the protein. More than 40 Belgian brewed commercial beers (gluten-free labeled, pils/lager, abbey, trappist, strong blond, amber, old brown, kriek and gueuze) and some foreign commercial beers are analyzed with R5 antibody sandwich ELISA gluten kit and competitive ELISA celiac-toxic peptide kits. The gluten content of the gluten-free labeled beers is in the range 5–8 ppm. The other beers have a gluten content from lower than the quantitative detection limit (5 ppm) to 101 ppm. Preliminary lab scale brewing experiments (60 Liter pilot brewery) and an industrial brewing case study revealed that the gluten content in the final beer can clearly be diminished by either using prolyl endopeptidase and/or tannins during the brewing processes. Even 100% barley malt beers can obtain a final gluten content much lower than the threshold of 20 ppm for food products to be declared ‘gluten-free’.