Changes

Microbial communities found on the outside surface of barley are very diverse and change significantly throughout the malting process, with more diversity occurring further along as the malting process continues. On barley in fields, Gram-negative bacteria (especially ''Erwinia herbicola'') are abundant. Climate is said to have the most impact on which species grow in barley fields. For example ''Fusarium'' species are encouraged by high humidity, and are associated with mycotoxins and gushing problems in beer. During dry storage of barley, spore forming bacteria tend to survive. Xerophilic fungi (fungi that doesn't need much water) also survive on dry barley during storage <ref name="Lievens1">[https://lirias.kuleuven.be/bitstream/123456789/323403/2/Just%C3%A9%20et%20al.%202011_Microflora%20during%20Malting%20of%20Barley%20Overview%20and%20Impact%20on%20Malt%20Quality.%20Brewing%20Science%2064,%2022-31..pdf Microflora during Malting of Barley: Overview and Impact on Malt Quality. A. Justé, S. Malfl iet, M. Lenaerts, L. de Cooman, G. Aerts, K. A. Willems and B. Lievens. 2011.]</ref>.

Microbial communities on the husks of barley change quite a bit during the malting process. It is thought that the factors affecting this are the initial microbe populations, interactions between species, the variances in the malted barley characteristics/processes, and additives. Different malting houses are likely to form "in-house" microflora populations. The first step in malting, which is steeping, sees the first large change in microbial populations. The steeping process favors lactic acid bacteria (LAB), which are seen only in very small numbers before steeping. Particularly these are ''Leuconostoc'' species. In the case of yeasts, ''Basidiomycota'' fungi grow, as well as ''Fusarium'' <ref name="Lievens1"></ref>.