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[[File:Long_Fermentation.jpg|thumb|upright=2.5|Conceptual graph of traditional microbe and wort dynamics|Conceptual graph of traditional souring microbe and wort dynamics. Y-axis for each microbe group depicts relative activity which combines in a conceptual sense: growth, acidification of wort, attenuation and production of flavor compounds. Plot drawn by Drew Wham based on concepts discussed in American Sour Beer <ref> Tonsmeire, M. (2014). American Sour Beers. Brewers Publications </ref> and Wild Brews <ref> Sparrow, J. (2005). Wild Brews: Beer Beyond the Influence of Brewer's Yeast. Brewers Publications</ref> . ]]
====Primary Fermentation====
Primary fermentation by ''Saccharomyces'' is generally conducted in the same way for a sour beer as for a non-sour beer. Depending on the intended final result the brewer might select a neutral ale strain (WLP 001/Wyeast 1056, WLP036/Wyeast 1007) to provide a neutral background for the souring microbes to act on. Alternatively, the brewer may use a Belgian strain or a saison/farmhouse strain (see ''[[Saccharomyces]]'' page for a comprehensive list) to increase the ester and/or phenol characters of the beer which can then be acted on by ''[[Brettanomyces]]''. Primary fermentation with ''Saccharomyces'' also tends to lend to more glycerol production which increases the beer's mouthfeel (''Brettanomyces'' generally does not produce much glycerol <ref>[http://www.milkthefunk.com/wiki/Brettanomyces#Secondary_Metabolites Brettanomyces; Secondary Metabolites. MTF Wiki. Retrieved 06/23/2016]</ref>). This primary fermentation can take place in any vessel suitable for a normal ''Saccharomyces'' fermentation. As always fermentation temperature control is of critical importance and temperature profiles for this fermentation step should match those suggested for the strain of ''Saccharomyces'' selected for this step. Once active fermentation has subsided the mostly attenuated wort can then be moved on to the secondary fermenting vessel. There is some variation in common practice as to whether or not the primary fermentation yeast should be carefully settled out, moving over bright clear beer only, or if un-settled cloudy high yeast population wort is moved to the secondary vessel. New Belgium moves their lager primary fermented beer after centrifuging, indicating that this centrifuged beer exhibits cleaner characters from secondary fermentation faster than un-centrifuged beer, allowing the resulting sour beer to be ready for packaging more quickly <ref> The Sour Hour Episode 2 with Lauren Salazar from New Belgium Brewing Company ]</ref>. Concerns of yeast autolysis, however, have generally been minimized by most brewers (see [[Mixed_Fermentation#Secondary_Fermentation|Secondary FermetnationFermentation]]).
====Secondary Fermentation====