Norwegian lambic-style acidic beers share key microorganisms and metabolites with Belgian lambic beers, although typical microbial phases are less pronounced

Sammendrag

Belgian-style acidic ale beers are gaining interest worldwide. These sour beers comprise the spontaneously fermented Belgian lambic beers and beers that are inspired by them, including American coolship ales. This study identified the microbiota present during Norwegian lambic-style acidic beer production processes, as well as the microbial metabolites produced. The production processes investigated were characterized by the addition of whole apples to the wort in the coolship. The four microbial phases typical for Belgian lambic beer production processes could be distinguished, although several phases overlapped. Apple surface microorganisms present did not appear to become dominant during fermentation under the conditions tested. During the first weeks of these processes, the enterobacterial species encountered were not yet associated with actual lambic beer production, and their presence could be related with high concentrations of 2,3-butanediol. These enterobacterial species indicated that the manual wort acidification, performed to prevent their growth, was insufficient. The main fermentation phase was characterized by the presence of Saccharomyces bayanus and Saccharomyces cerevisiae, although they were present in different barrels and not simultaneously. Pediococcus damnosus and several Brettanomyces species characterized the overlapping acidification and maturation phases, during which the complete consumption of maltooligosaccharides and the production of lactic acid, acetic acid, ethanol, ethyl lactate, ethyl acetate, and 2,3-butanediol were encountered. No acetic acid bacteria were found during the maturation phase, likely because a pellicle formed by Brettanomyces did influence oxygen presence, while the characteristic production of the volatile phenolic compounds ethyl guaiacol and ethyl phenol took already place during the first month of the production processes.

Les publikasjonen her:

DOI : doi.org/10.1016/j.heliyon.2026...
NVA : hdl.handle.net/11250/5581087