Effects of the mashing process and macromolecule contents on the filterability of barley malt.

The filterability of barley malt is a critical quality parameter in beer brewing. The effects of two mashing processes (processes A and B) on the filterability of the three barley malts and their macromolecule contents were investigated. Filtration volume increased by 4%, 9%, and 13% for the Baudin, Ganpi, and Gangpi malts, respectively, and the final filtration volume of Gangpi was still poorer than that of Baudin. A downward mashing process (process C) was applied to measure the β-glucan, arabinoxylans (AX), the polymeric arabinoxylan (PAX), and high molecular weight nitrogen (HMWN) content. The β-glucan degradation rate of well-modified malt during malting was higher than that of poorly modified malt, whereas the PAX and HMWN solubilization rates during malting were lower in well-modified malt than in poorly modified malt. The filterability of poorly modified malt did not effectively improve with an initial mashing phase at 37℃. β-Glucan degradation and PAX and HMWN solubilization during malting were critical for ensuring malt quality. Thus, the goal of predicting the filterability of malt was achieved by applying a downward mashing process. PRACTICAL APPLICATION: Quality of wort and beer as well as production efficiency is affected by the malt quality. The filterability of barley malt can affect the production efficiency and quality of wort. The change in the macromolecule contents during malting is important to ensure the production of high-quality malt. The results of this study can provide a good method for the detection of malt filtration performance, and it also may contribute to the purpose of prediction the changes in barley malt and the resulting barley malt filterability.