Preliminary microbiological and chemical analysis of two historical stock ales from Victorian and Edwardian brewing

Historical beers are a valuable source of information on past brewing microbiology providing opportunity for analysis and isolation. Although rarely found intact and suffering variable degrees of deterioration they can contain living microbial cells and residues of chemical components indicating the character of the beers and their production processes. This report summarises preliminary analysis of two beers from Victorian and Edwardian times and provides an indication of their chemistry and microbiology. One beer, recovered from the 1895 Scottish shipwreck Wallachia, was a 7.5% ABV stout, the other an 11% ABV celebration King's Ale, a barley wine, brewed by Bass in 1902 for the visit of King Edward VII. Live yeast was isolated from both beers: Brettanomyces and Debaryomyces from the Wallachia stout and Saccharomyces from the Bass Ale. Ribosomal DNA amplicon sequencing indicated the presence of a wide range of microorganisms in both beers including lactobacilli and pediococci in the Wallachia beer and staphylococci in the Bass Ale. Both beers are likely to be in the category of stock ales of the time and would have been matured for a period before bottling. The presence of Brettanomyces bruxellensis in both beers confirms the understanding of this species as an important contributor to these beers but it is also interesting that Debaryomyces species are consistently present as a major component and that Saccharomyces are less prevalent. © 2021 The Institute of Brewing & Distillin