Ohwofasa, AghoghoDhami, ManpreetWinefield, ChristopherOn, Stephen2025-02-112025-01-212025-022024-12-262076-2607https://hdl.handle.net/10182/18088Beer produced by autochthonous microbial fermentation is a long-established craft beer style in Belgium that has now been implemented commercially in New Zealand. We used a metabarcoding approach to characterize the microbiome of 11 spontaneously fermented beers produced by a single brewery in Oamaru from 2016 to 2022. Key organic acid concentrations were also determined. Both bacterial and fungal populations varied considerably between vintages and between individual brews produced in 2020. Similarly, for organic acids, the concentrations of L-malic acid, succinic acid, and L-lactic acid statistically differed from one vintage to another. Moreover, a correlation between the concentrations of certain organic acids and microbial composition was inferred by ordination analyses. Through reference to publicly available climate data, humidity and maximum temperature seemed to enhance the abundance of Penicillium and Hanseniaspora in beer microbiota. However, comparison with previously published studies of Belgian lambic beers, similar Russian ales, and publicly available temperature data from these regions showed that the microbial populations of these were relatively stable despite greater extremes of weather. Our results suggest that while climatic variables may influence microbial populations during beer making that employs autochthonous fermentation in New Zealand, such variation is not evident where similar beers are produced in facilities with a long-established history of production. These findings have implications for lambic-style beer production in the context of global climate change, notably where microbial populations may lack environmental adaptation.17 pagesen© 2025 by the authors. Licensee MDPI, Basel, Switzerland.climate changelambic beermetabarcodingmicrobial diversityspontaneous fermentationJournal Article10.3390/microorganisms130202242076-2607ANZSRC::300601 Beverage chemistry and beverage sensory scienceANZSRC::310603 FermentationANZSRC::370299 Climate change science not elsewhere classifiedANZSRC::3107 MicrobiologyANZSRC::3207 Medical microbiologyhttps://creativecommons.org/licenses/by/4.0/Attribution