Isothermal Mashing of Barley Malt: New Insights into Wort Composition and Enzyme Temperature Ranges

Abstract

The basic step in beer production is mashing, during which insoluble starch chains, and to a lesser extent cell walls and proteins are broken down by enzymatic hydrolysis. Since the beginning of the modern brewing process there have been empirical studies into the optimum effective temperatures of the corresponding enzymes, and mashing has been carried out accordingly. The resulting resting temperatures of proteolysis, cytolysis and amylolysis with the maltose and saccharification rest, are now rarely changed, only being adapted to the properties of the raw materials used to a limited extent. New varieties of barley and other raw materials used in breweries, as well as modern processes in malting plants, ensure better enzyme potential and optimized malt gelatinization temperatures. The aim of this paper is to determine enzyme activity in barley malt during mashing. For this purpose, isothermal mashing was used, i.e., a mashing process with a constant resting temperature over the entire mashing period. The obtained worts were analyzed for the attributes of extract, final attenuation, β-glucan, total nitrogen, free amino nitrogen, viscosity, and pH as well as sugar composition and individual amino acids. The change in these attributes indicates the enzyme activity of the malt.

Multi-Response Optimization of the Malting Process of an Italian Landrace of Rye (Secale cereale L.) Using Response Surface Methodology and Desirability Function Coupled with Genetic Algorithm

“…In order to ensure its reduction to levels that allow for good filtration, enzyme activity must be promoted by appropriate timing and temperatures during brewing. Indeed, as amylolytic enzyme efficiency decreases as a result of an excessive shift from their temperature optimum, viscosity tends to rise [ 59 ]. The lowest viscosity levels were obtained in malts with extracts close to or above 83%.…”

Effective strategies to maximise dextrin formation in brewing

“…These differences may be linked to the activity of invertase, which hydrolyses sucrose into glucose and fructose. Invertase is optimally active at 50°C and is rapidly inactivated at temperatures above 55°C (Laus et al 2022). As a result, invertase was inactivated faster during the mashing scheme with a high heating rate, resulting in reduced sucrose hydrolysis (Langenaeken et al 2020).…”

“…Additionally, Evans et al ( , 2022) have highlighted the significance of limit dextrinase which is positively related to the content of fermentable sugar and negatively related to the dextrin content of the wort. Malt α-amylase randomly cleaves the α-(1,4) bonds of gelatinised and non-gelatinised starch, whereas malt beta-amylase liberates β-maltose from the non-reducing ends of gelatinised starch (Bijttebier et al 2008;Vriesekoop et al 2010;Laus et al 2022). Malt limit dextrinase is a debranching enzyme hydrolysing the α-(1,6) branching sites of starch.…”

“…Malt limit dextrinase is a debranching enzyme hydrolysing the α-(1,6) branching sites of starch. Notably, malt beta-amylase, limit dextrinase, and α-amylase are optimally active at distinct temperature ranges of (respectively) 60-65, 60-63, and 65-75°C and are inactivated once these temperatures are exceeded (Muller 1991;Evans and Fox 2017;De Schepper et al 2022b;Laus et al 2022).…”

Effect of mashing temperature on fermentation and antioxidant capacity of Qingke wort

“…Among these factors, temperature is considered one of the most critical variables affecting the mashing process and wort quality. Temperature influences the progress of enzymatic reactions (Laus et al, 2022) and the efficiency of substance leaching (Zhao et al, 2010) during mashing. These reactions ultimately determine the composition and quality of the resulting wort.…”