Changes

Just like in other yeast species, the temperature has a direct effect on the rate of fermentation for ''Brettanomyces''. The optimal fermentation rate temperature range for ''Brettanomyces'' is between 22-32°C (77-90°F), however one study by Tyrawa et al. found that several strains of ''B. bruxellensis'' fermented at 30°C "smelled terrible" <ref name="Tyrawa_2017" />. Fermentation At 20°C (68°F) fermentation rate is about half as slow at 20°C (68°F). ''Brettanomyces'' will still grow at temperatures as low as 15°C (and maybe lower than59°F) 15°C with about a third of strains being able to grow as low as 10°C (59°F50°F) <ref name="Conterno_2006">[http://www.ajevonline.org/content/57/2/139 Genetic and Physiological Characterization of Brettanomyces bruxellensis Strains Isolated from Wines. Lorenza Conterno, C.M. Lucy Joseph, Torey J. Arvik, Thomas Henick-Kling, Linda F. Bisson. 2006.]</ref><ref>[https://www.ncbi.nlm.nih.gov/pubmed/24290676 Impact of sulfur dioxide and temperature on culturability and viability of Brettanomyces bruxellensis in Wine. Zuehlke JM, Edwards CG. 2013. DOI: 10.4315/0362-028X.JFP-13-243R.]</ref> but growth will be much slower. However, however one study showed a slightly higher viability during the full-time period of fermentation at 15°C as opposed to the optimal growth and fermentation temperature range of 20-32°C. The growth rate at 15°C, while still slowly active, varies from strain to strain with some strains growing very poorly. Carbohydrates are consumed much slower, with cellobiose metabolizing ceasing for some strains (although phenol production stayed the same between 15°C and 22.5°C) <ref name="Tyrawa_2017" />. At a temperature of 35°C (95°F), fermentation is greatly inhibited due to cell deathfor most strains, with about a third of strains able to grow as high as 37°C (98.6°F) <ref name="Conterno_2006" />. The primary byproducts of ''Brettanomyces'' fermentation, which are ethanol, acetic acid, and CO2, are produced both during growth but also during fermentation after growth has stopped. At the more optimal fermentation temperatures of 25-32°C, ethanol and acetic acid are produced faster from fermentation, but the amounts of ethanol and acetic acid produced from fermentation are not affected by temperature (i.e. higher temperatures do not produce more ethanol and acetic acid from the same amount of sugar, they are just produced faster at warmer temperatures because fermentation is faster) <ref name="Brandam_2008" />. The warmer temperature ranges that are ideal for ''Brettanomyces'' fermentation rates and growth rates may still produce unfavorable flavors such as higher alcohols, however, this has not been analyzed as far as we know <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1555689637792578/ MTF conversation with Richard Preiss of Escarpment Labs. 01/20/2017.]</ref>.