Impact of bacteria on beer appearance and flavour

Relative to the impact of yeast on beer appearance and flavour as discussed above, information is scarce on the impact of bacteria on beer appearance and flavour. Bacteria mainly cause turbidity, sediments, acidification, off-flavour formation and ropiness (Sakamoto Konings, 2003 Suzuki, 2011 Suzuki et al., 2008). Suzuki (2011) and Vriesekoop, Krahl, Hucker, and Menz (2012) recently sununarised the positive and negative influences of bacteria on flavour and off-flavour in recent reviews, which form the basis of this section. Interested readers are referred to these articles for further details. 

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This chapter is divided into five sections including an introdnction (Section 17.1), impact of yeast on beer appearance (Section 17.2), impact of yeast on beer flavour (Section 17.3), impact of bacteria on beer appearance and flavour (Section 17.4), and future trends (Section 17.5). The emphasis is on the impact of yeast on beer appearance and flavour because more information is available on this topic. Although most of the discussions are centred on the impact of main brewing yeast strains (Saccharomyces cerevisiae and Saccharomycespastorianus) on barley malt-based beers (ale and lager, respectively) (Lodolo, Kock, Axcell, Brooks, 2008 Stewart, Hill, Russell, 2013), references are also made to other yeasts involved in brewing specialty beers derived from both barley malt and other cereal malts. Lactic acid bacteria (LAB) are the focus of discussion with regard to bacterial impact on beer appearance and flavour due to their relatively common occurrences in beers (Menz et al., 2010 Sakamoto Konings, 2003 Suzuki, 2011 Suzuki, Asano, lijima, Kitamoto, 2008). 

Impact of yeast and bacteria on beer appearance and flavour... 

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