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→Brettanomyces dominance
[[file:Brettanomyces_micrograph.jpg|thumb|right|Brettanomyces sp.]]
Brettanomyces inherits the role of most prominent yeast genera from Saccharomyces around 8 months, and continues consuming sugars in the wort. Final attenuation can reach over 80% in lambic through the continued action of Brettanomyces, which is often referred to as "overattenuation" or "superattenuation". This is greater than is usually possible with Saccharomyces alone, as Brettanomyces is able to metabolise sugars that Saccharomyces cannot, generally known as "dextrins".In addition, brettanomyces can metabolise laminarin and pectin. There is some inter-strain variability on what sugars Brettanomyces can metabolize (arbutin, β-methyl-D-glucoside, et al. are only metabolized by some strains of Brettanomyces.)<ref name=Crauwels1> S. Crawels et. al. [http://link.springer.com/article/10.1007%2Fs00253-015-6769-9| Comparative phenomics and targeted use of genomics reveals variation in carbon and nitrogen assimilation among different Brettanomyces bruxellensis strains], 2015</ref>
Brettanomyces has been implicated in producing most of the aroma compounds in Lambic.<ref name="Guinard">Jean-Xavier Guinard, [[Books#Classic Beer Styles: Lambic|Classic Beer Styles: Lambic]], 1990</ref> Sensory-significant quantities of ethyl acetate and ethyl lactate form at this time from ethanol entering into an ester bond with [[Acetic acid|acetic]] and [[lactic acid]], respectively. In addition, ethylphenols formed from hydroxycinammic acid contribute an odor often described as "horse sweat", "barnyard", or "leather" <ref name=Crauwels1> S. Crawels et. al. [http://link.springer.com/article/10.1007%2Fs00253-015-6769-9| Comparative phenomics and targeted use of genomics reveals variation in carbon and nitrogen assimilation among different Brettanomyces bruxellensis strains], 2015</ref>. The esterization process is greatly helped by the enzyme esterase provided by Brettanomyces. However, the enzymatic esterization is highly reversible and esters found in high concentrations in the lambic prior to the presence of the esterase will often achieve a lower equilibrium at the end of fermentation. This is the case with iso-amyl acetate, which is produced by Saccharomyces and is a characteristic odor compound in many other beers.