Specialty beer production and processes

Wheat beers utilize raw or malted wheat, rather than malted barley, as their primary raw material base. Fermentation may be spontaneous (natural flora of the brewery, Belgian Lambic beers [see below]) or with a top fermentation yeast strain. South German wheat beers (weissbier) utilize a top fermenting yeast strain that produces a characteristic phenolic flavor (4-vinyl-guaiacol, dove-like see Table 18.3 Anderson et al., 2000 McMurrough et al., 1996 Stewart Russell, 1998 Vanbeneden, Gils, Delvaux, Delvaux, 2008). Certain wild yeasts can produce phenohc off-flavors in nonwheat beer styles and as such would be regarded as contaminants. 

White beer (weissbier) is a special beer that is very pale in color. A lactic fermentation is carried out following the addition of a starter culture resulting in a very low pH 3.2-3.4. Lactobacillus brevis, a top fermenting yeast, and Brettanomyces bruxellensis are used in fermentation resulting in pure lactic acid flavor (Anderson et al., 2000 Back, 2005 Vriesekoop et al., 2012). Sensory panels would need to ensure the quality of the pure lactic acid flavor and lack of any contaminant-generated off-flavors in such highly acidic/tart beers. 

7 Specialty beers—wood- and barrel-aged beers 

Another new class of beers emerging, as well as an understanding of early traditional wooden and cask-aged beers, will require sensory studies based on the effect of the microflora present in such barrels. This topic involves understanding a unique set of flavor notes derived also from the wood itself. New flavor wheels describing wood-and barrel-aged flavors are available, and a lot of current research into the production of such beers is underway. Sensory programs as described in Part 2 can be initiated to study these unique beer styles. 

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