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SYNTHESIS OF AROMA COMPONENTS DURING THE SPONTANEOUS FERMENTATION OF LAMBIC AND GUEUZE
Author(s) -
Oevelen D. Van,
L'Escaille F.,
Verachtert H.
Publication year - 1976
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1975.tb06953.x
Subject(s) - fermentation , isoamyl acetate , aroma , lactic acid , acetic acid , brewing , ethyl lactate , chemistry , food science , mixed acid fermentation , ethyl acetate , ethanol , isoamyl alcohol , butyric acid , lactic acid fermentation , biochemistry , chromatography , bacteria , organic chemistry , alcohol , biology , genetics , catalysis
Lambic is a type of Belgian beer obtained by spontaneous fermentation of wort. The fermentation in casks takes almost two years, and after that period the beer may be re‐fermented in bottles and is then called gueuze. To gain insight into the many microbiological transformations occurring during this process, a qualitative and quantitative study of several components formed over a two‐year period was undertaken. It was found that lambic and gueuze are characterized by high contents of ethyl acetate, ethyl lactate, lactic acid and acetic acid. Two phases of fermentation may be distinguished: a primary phase lasting for about three months during which almost all the ethanol and higher alcohols are formed and a very long secondary phase during which lactic acid is formed first, followed by ethyl lactate. Some lower fatty acids, including all the acetic acid, are made at the very beginning of the first phase. An important part of the ethyl acetate is made during the first phase but the amounts increase slowly to high levels during the second phase. Unusually low amounts of isoamyl acetate are detected. Several components are above the reported threshold levels of taste and are thus probably involved in the genesis of the typical aroma of lambic and gueuze. These results will allow a further study of the relations between the components found and the microbial populations involved in the spontaneous fermentation inherent in the brewing of lambic and gueuze.