Modification of the Malting Process of Barley Grains of Different Varieties by Vacuum Impregnation and Its Effect on Selected Wort Parameters

Abstract

This study used the process of vacuum impregnation of seeds at the soaking stage. The barley varieties used were Kangoo and Xanadu. The raw material was used for the production of light malt. The effect of vacuum impregnation on the rate of water uptake by the seeds at different temperature conditions, i.e., 12, 14 and 16 °C, was also analyzed. Grain destined for malt was soaked in a water–air system. The germination (malting) stage lasted 8 days at temperatures of 12, 14 and 16 °C. Each sample was then dried using the traditional convection method. After a 3-month resting period, congress wort was produced from the malt. The wort parameters studied were the viscosity index and the wort extract content. The malt extract difference was also defined. Based on the results, it was concluded that the vacuum impregnation process significantly increases the absorption of water by the grain and thus shortens the soaking and germination stage of the seeds. Grain variety has a strong influence on extract content and wort viscosity. Malting temperature only affects the viscosity index. The most important correlations of the parameters studied were noted for the number of days the grains were malted.