Optimization of malting and mashing processes for the production of gluten-free beers
2011
Kiss, ZS. | Vecseri-Hegyes, B. | Kun-Farkas, G. | Hoschke, Á
In the course of our work we aimed to develop a product from gluten-free raw materials (millet, sorghum and buckwheat) that is similar to beer made of barley malt but is consumable by coeliacs. Our measurements were started by qualification of cereal/pseudo-cereal grains. Next malts were made of them with different steeping, germination and kilning parameters, and their most important quality characteristics were determined. Qualification of grains were done by grading, determination of thousand-kernel and hectolitre weight, and protein content, while malts were examined with congress mashing, Hartong mashing and lauter test, as well. Gelatinization point of the starch found in grains and malts were determined by Brabender amyloviscograph which helped to set the temperature of β-amylase rest in future mashings. The gelatinization points were higher in our samples, than in the barley’s starch.Optimization of mashing was continued with malts that fulfilled requirements needed for brewing. Mashing programs were written for each raw material with the help of our laboratory mashing equipment, and resulting worts were analysed (for extract content), then carbohydrate content was measured by HPLC, α-amylase activity by Phadebas test, and free α-amino nitrogen (FAN) content by the ninhydrin method. Those worts were selected for further fermentation tests that had the highest extract and FAN content, best filtration time and appropriate sensory characteristics. Optimal malting temperatures and time periods, aeration and water uptake were determined, and then the duration and temperature of protein and enzyme rests of mashing were set.The malting process that proved to be the most suitable for brewing requirements (high extract content, good lautering characteristics, high FAN content) has the following parameters: steeping with 25 °C water for 18 h with aeration in every 5 h; germination at 15 °C for 84 h; kilning at 50 °C for 48 h.
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