A Comparative Study of Dry and Wet Milling of Barley Malt and Its Influence on Granulometry and Wort Composition

Felipe Pereira De Moura,Thiago Rocha Dos Santos Mathias

doi:10.3390/beverages4030051

Felipe Pereira De Moura, Thiago Rocha Dos Santos Mathias

Open Access

https://doi.org/10.3390/beverages4030051

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Abstract

Beer is a fermented drink produced from a wort comprised of barley malt, hops, and water in combination with activity from the yeast strains of the genus Saccharomyces. The beverage is consumed around the world and has a global market controlled by several multinational companies. However, in recent years, it has been possible to note an increase in the number of microbreweries and homebrewers, necessitating additional research both to develop and increase competitiveness of this market sector as well as to improve product quality and promote the reduction of production costs. The process of milling barley malt is often not considered relevant to these goals; however, this operation is influential with regard to, for example, mashing yield, the concentration of polyphenols in beer, and the quality of wort clarification. Therefore, this work evaluates the wet (10%, 20%, 30%, 40%, and 50% moisture content) and dry barley malt milling process as well as analyzes particle size distribution and the mean diameter of particles. The milled grains were submitted to a mashing process to evaluate how particle size contributes to the conversion of starch to sugars and the availability of polyphenols on sweet wort. The results indicate the best milling conditions to obtain a good mashing yield while preserving as much malt husk as possible to facilitate wort clarification.

Highlights

Beer is produced by the alcoholic fermentation of wort, which is prepared with barley malt and water, hop addition, and yeast action (Saccharomyces genus) [1,2]
Excessive milling promotes the extraction and solubilization of compounds whose presence causes the increase of undesirable characteristics to wort and beer, e.g., sensory properties such as an excessive bitterness or viscosity
70–80% of the total polyphenol content of beer comes from the malt husk; its transfer to the wort is influenced by cereal milling [8]

Summary

Introduction

Beer is produced by the alcoholic fermentation of wort, which is prepared with barley malt and water, hop addition, and yeast action (Saccharomyces genus) [1,2]. The process can be divided into the following steps: malting, milling, mashing, boiling, cooling, fermentation, filtration, carbonation, microbiological stabilization, and packaging. Milling has an important role in the process both in the professional beverage industry and in homebrew production because, in this step, the barley husk breaks down, exposing the starchy endosperm and the content of the embryo (predominantly enzymatic) [3,4]. Excessive milling promotes the extraction and solubilization of compounds whose presence causes the increase of undesirable characteristics to wort and beer, e.g., sensory properties such as an excessive bitterness or viscosity. 70–80% of the total polyphenol content of beer comes from the malt husk; its transfer to the wort is influenced by cereal milling [8]

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