Changes

Wort can be soured in the primary fermenter before adding other yeasts. This is generally a good approach for brewers who aren't concerned with pasteurization and infections of their cold side equipment. This has the advantage of possibly producing a more complex sour beer overall, or at least a sour beer that will evolve over time. It has the advantage over a more traditional [[Mixed Fermentation]] in that ''Lactobacillus'' is used to guarantee at least a certain level of sourness. This is also a good process to use for making a [[Berliner Weissbier]].

Once cooled to the desired temperature (usually around 90-115°F or 32.2-46°C), the wort is racked to the primary fermenting vessel. Note that the wort should contain a low amount of IBU's when using this process since IBU's can inhibit many (but not all) species of ''[[Lactobacillus]]''. Using no hops is a good approach to getting more acidity, but if hops are required then than using less than 6 IBU's is a good guideline in general (consider mash hopping; mash hopping has been reported to reduce IBU's by ~70% <ref>[http://www.homebrewersassociation.org/how-to-brew/resources/conference-seminars/ ''Putting Some Numbers on First Wort and Mash Hop Additions''. David Curtis NHC 2014 Presentation.]</ref>). It is generally a good idea to create a 500 mL starter beforehand for ~5-6 gallons of wort (see [[Lactobacillus#Starters_and_Pitching_Rate|''Lactobacillus'' starters]]). Once the wort is racked to the primary fermenting vessel, the ''Lactobacillus'' culture is added directly to the fermenter. No other yeasts are added at this time. The ''Lactobacillus'' bacteria is allowed to incubate by itself in the wort for 21-5 3 days with the before mentioned target temperature maintained throughout the incubation period (some ''Lactobacillus'' species/strains may continue to produce acidity under lower temperatures). The exact time frame of incubation depends on the species/strain of ''Lactobacillus'', the manufacturer's recommendation, and the brewer's desired acidity level. Acidity can safely be measured with a reliable pH Meter throughout this time. If possible, it is advised that the brewer fill fills the head space of the fermenter with CO2. Some brewers have reported that this helps to reduce sulfur production, but if ''Brettanomyces'' is added to the beer later on in the process and allowed to age, this shouldn't be a concern.

After the desired acidity level is reached from the incubating ''Lactobacillus'' bacteria, the brewer can crash cool the fermenter down to the temperature that is desired for the primary fermenting yeast. Both ''[[Saccharomyces]]'' and ''[[Brettanomyces]]'', or a blend can be used as primary fermenting yeast. ''Brettanomyces'' is often chosen because of it's higher tolerance of a low pH environment (3.4- pH <ref name="low ph">[http://www.homebrewtalk.com/f127/no-hop-berliner-weisse-415067/index3.html#post5280971 Michael Tonsmeire on HBT]</ref>), although many ''Saccharomyces'' strains have been successfully used (see the [[Wort_Souring#Souring_in_the_Boil_Kettle|Souring in the Boil Kettle]] section above). If the chosen yeast requires aeration and the brewer has the ability, the sour wort should be aerated before pitching yeast. Brewers have had good luck using Fermentis dry yeast products in the non-aerated wort. Re-hydrating the dry yeast as per the manufacturer's instructions and with a yeast nutrient such as Go-Ferm is effective <ref>[http://www.scottlab.com/product-102.aspx Go-Ferm]</ref>. The wort is then fermented out as normal. The brewer can consider other [[Brewing Methods]] such as pitching ''Brettanomyces'', a mixed culture, or commercial sour beer dregs into secondary.