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→Modern Analysis
===Modern Analysis===
A more recent study by Snaewaert et al. (see reference <ref name="snauwaert"></ref>) looked at the microbial and metabolic composition in the finished beer of the same brewery as Martens et al., as well as two other Flemish red-brown beer breweries using "state of the art" DNA sequencing methods. Three samples were analyzed (A, B, and C) from each brewery (1, 2, and 3). As expected, there were both similarities and differences between the three breweries tested, as well as some differences between the individual beers from each brewery. See [[Flemish_Red-Brown_Beer#Microbial_Populations|Microbial Poulations]] below. In 2022, Dusart et al. analyzed and compared flavor compounds of a bottle of 2015 Rodenbch Vintage, a 2021 bottle of Rodenbach Grand Cru, and a 2021 bottle of Liefmans Goudenband, using solvent-assisted flavor evaporation (SAFE) and static headspace analysis, followed by GC-MS analysis. They also included n-Hexanol extraction of short-chain fatty acids and HPLC analysis of iso-alpha acids <ref name="Dusart_2022" />
====Microbial Populations====
Overall the flavor of these beers was dominated by ethanol, lactic acid, acetic acid, ethyl acetate. Across the samples there was also a presence of isoamyl alcohol (31-150mg/L) and isoamyl acetate (1.99-6 mg/L), and an absence of 2-phenyl ethanol and 2-phenylethyl acetate in both the matured beers and the bottles versions. Small amounts of propionic acid, isobutyric acid, ethyl hexanoate, and ethyl octanoate were found. Higher levels of ethyl acetate were found compared to the Martens et al. study, and no ethyl decanoate was found, which is a typical ester found in gueuze. Just as the microbial populations of Brewery 2 differed from Breweries 1 and 3, so did its overall metabolite content. Higher levels of acetic acid were found in Brewery 2, which was attributed to high levels of ''Acetobacter'' populations. Additionally, all three of the samples from Brewery 2 differed from each other as far as metabolic content, which was also attributed to the microbial population differences between each of Brewery 2's samples <ref name="snauwaert"></ref>.
====Rodenbach vs Liefmans Analysis====
==Style Guidelines==