Gueuze beers

According to Verachtert (81), "lambic is the fermented wort and gueuze is derived from it after a secondary fermentation in the bottle... when cherries or extract are added during fermentation, the gueuze may be named kriek, and when raspberries are added it is called frambois ". Brettanomyces species predominate in the latter part of the main fermentation and in bottles of lambic and gueuze beers. 

Reviewing the primary tastes in beer its sourness will be measured either as its pH (3-8-4-7) or as its titratable acidity. The level of acetic acid reported for normal beers (57-145 ppm) is below the taste threshold (400 ppm) and the same is true of lactic acid (Table 22.7). Infection of beer with microorganisms such as Acetobacter and Lactobacillus spp. may reduce the pH and produce a sour taste. Thus with lambic and gueuze beer the pH may drop to pH 3 2. The level of acetic acid in these beers is 2 6-6-9 times the taste threshold and the level of lactic acid is 5-8-8-6 times its taste threshold [24]. 

Spitaels E, Van Kerrebroeck S, Wieme AD, Snauwaert I, Aerts M, Van Landschoot A, De Vuyst L, Vandamme P (2015a) Microbiota and metabolites of aged bottled gueuze beers converge to the same composition. Food Microbiol 47 1-11... 

Belgian beer. Brettanomyces species are essential in the production of characteristic fruity, ester-like aromas of spontaneous fermented Belgian beers (78, 79) lambic, gueuze, kriek, and frambois. Others have described Ihe Brett aroma in traditional Belgian beer as "smelling like horse sweat" it is "the deliberate signature of the style" (80). 

Verachtert, H., Iserentant, D. (1995). Properties of Belgian acid beers and their microflora. I. The production of gueuze and related refreshing acid beers. Cerevisia (1), 37—41. 

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