_applied sciences_  
_Article_  
The Use of Vacuum Impregnation of Barley Grain in the Production of Malt for Wort  
[PERSON] 1, [PERSON] 2,*(r), [PERSON] 2, [PERSON] 1 and [PERSON] 1(r)  
1 Department of Biological Bases of Food and Feed Technologies, University of Life Sciences in Lublin, Gleboka 28, 20-612 Lublin, Poland 2 Department of Food Engineering and Machines, University of Life Sciences in Lublin, Gleboka 28, 20-612 Lublin, Poland * Correspondence: [EMAIL_ADDRESS]  
**Featured Application: This study shows that the use of the vacuum impregnation process of barley grain for the production of light malt significantly reduces the soaking time of the grain, which speeds up the malt production process without causing significant negative changes in the parameters of wort. Vacuum impregnation is not used in industrial beer production. However, it can be quickly implemented with a small investment, i.e., the purchase of a vacuum pump and vacuum chamber. **  
In this study, the process of the vacuum impregnation of Kangoo barley grain, at the stage of soaking, was used in the production of light malt. The influence of vacuum impregnation on the speed of the water uptake by the barley, at temperatures of 12, 14, 16 and 18 \({}^{\circ}\)C, was also analyzed. At this stage of the research, the grain was soaked in water to obtain a moisture content of approximately 42%. The samples for the moisture content tests were taken every 2 h. The grain intended for malt was soaked in an air-water system and was kept submerged in water for 6 h. It was then removed from the water and kept for 18 h. The grain was aerated during the soaking process. The malting and soaking lasted eight days at temperatures of 12, 14, 16 and 18 \({}^{\circ}\)C. The samples for further testing were taken daily. Then, each of the samples was dried, following the same procedure. The sprouts were removed immediately after the dried samples contained approximately 4% moisture. Following a 3-month maturation process, the copress work was produced from the malt. The pH and the extract content in the wort were tested. It was found that the process of vacuum impregnation significantly accelerates the uptake of water by the grain. In almost all cases, the influence of the tested factors on the pH of the wort and the extract content was also observed. vacuum impregnation; malt; barley; wort  
14 December 2022  
1  
Received: 24 January 2023  
Accepted: 25 January 2023  
Published: 27 January 2023  
**Copyright:** 2023 by the authors. Liconse MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)]([https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/))). **1. Introduction**  
Impregnation, i.e., filling materials with additional liquid components, has been a known and widely used process for over 100 years. Since the end of the 1960s, the appearance of and the expansion in the use of the impregnation process under reduced pressure conditions can be observed on an industrial scale. Such impregnation is called vacuum impregnation, in both the scientific and trade literature. Its importance can be proven by the fact that it is among the processes covered by the standards of the American defense industry (MIL-STD-276A) [1]. In traditional applications, the purpose of impregnation is to ensure tightness and to eliminate the porosity of various materials. It is mostly used in the production of engine blocks and cylinder heads in the automotive industry, as well as in power systems, brake systems and landing gear components in the aviation industry. The knowledge already gathered allows us to state that impregnation is a process that modifies the structure and the sensory and functional properties of products and increases their physicochemical stability by creating a coating of liquid material on the surface of a solid body [2; 3].