title: Microbiota and metabolites of aged bottled gueuze beers converge to the same composition.
abstract: Gueuze beers are prepared by mixing young and old lambic beers and are bottle-refermented spontaneously for aging. The present study analyzed the microbiota and metabolites present in gueuze beers that were aged between a few months and up to 17 years. Yeasts were cultivated from all beers sampled, but bacteria could not be grown from beers older than 5 years. Lactic acid and ethyl lactate concentrations increased steadily during aging, whereas ethanol concentrations remained constant. The concentrations of isoamyl acetate and ethyl decanoate decreased during the aging process. Hence, ethyl lactate and ethyl decanoate can be considered as positive and negative gueuze beer-aging metabolite biomarkers, respectively. Nevertheless, considerable bottle-to-bottle variation in the metabolite profiles was found, which hindered the generalization of the effects seen during the aging of the gueuze beers examined, but which illustrated the unique character of the lambic beers. The present results further indicate that gueuze beers are preferably aged for less than 10 years.
authors.affiliation: Laboratory of Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
authors.forename: Freek
authors.initials: F
authors.lastname: Spitaels
authors.affiliation: Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Simon
authors.initials: S
authors.lastname: Van Kerrebroeck
authors.affiliation: Laboratory of Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium; Laboratory of Biochemistry and Brewing, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium.
authors.forename: Anneleen D
authors.initials: AD
authors.lastname: Wieme
authors.affiliation: Laboratory of Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
authors.forename: Isabel
authors.initials: I
authors.lastname: Snauwaert
authors.affiliation: Laboratory of Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Aerts
authors.affiliation: Laboratory of Biochemistry and Brewing, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium.
authors.forename: Anita
authors.initials: A
authors.lastname: Van Landschoot
authors.affiliation: Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: De Vuyst
authors.affiliation: Laboratory of Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium. Electronic address: Peter.Vandamme@UGent.be.
authors.forename: Peter
authors.initials: P
authors.lastname: Vandamme
mesh_terms: D001419:Bacteria / Q000145:classification / Q000302:isolation & purification*; D001515:Beer / Q000032:analysis* / Q000382:microbiology*; D003651:Decanoates; D000431:Ethanol / Q000032:analysis; D005285:Fermentation; D007773:Lactates / Q000032:analysis; D019344:Lactic Acid / Q000032:analysis; D064307:Microbiota; D000439:Pentanols / Q000032:analysis; D015003:Yeasts / Q000145:classification / Q000302:isolation & purification*
chemical_list: D003651:Decanoates; D007773:Lactates; D000439:Pentanols; D019344:Lactic Acid; D000431:Ethanol; C015866:ethyl lactate; C091960:ethyl decanoate; C020377:isoamyl acetate
keywords: Beer aging; Dekkera; Ethyl decanoate (PubChem CID: 8048); Ethyl hexanoate (PubChem CID: 31265); Ethyl lactate (PubChem CID: 7344); Ethyl octanoate (PubChem CID: 7799); Gueuze beer; Isoamyl acetate (PubChem CID: 31276); Lactic acid (PubChem CID: 612); Maltotriose (PubChem CID: 439586); Metabolites; Microbiota; Spontaneous bottle refermentation