The impact of microorganisms on barley and malt quality - A review

Microbial colonization of the barley plant tissue occurs in the field while the crop is growing. Accordingly, all barley grain/seed will have some microflora, although the amount and type of microorganisms may vary. Barley is one of the major raw materials used for brewing, and microflora on barley has long been associated with a number of quality aspects and brewing issues that form the subject of this review. Specifically, this review will focus on the impact of barley microflora on the malting process and malt quality, wort production and resulting wort quality, the fermentation process and yeast flocculation, and the final product (beer) quality. In addition, we will briefly review antimicrobial factors associated with the microflora of plant tissue (including seeds), specifically focusing on how these factors occur, some typical factors, and their possible impact on brewing.