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small updates to Lactobacillus fermentation
The process is very similar to the kettle souring technique, except the wort is never pasteurized after it is soured. The all grain brewing process is the same for any all grain brewing process, except that after the boil the beer is only chilled to the recommended temperature for the ''Lactobacillus'' strain that the brewer is going to use. Using grain husks for souring with this method is not advised since the grain will stay in the fermenter during primary fermentation, and unwanted microbes on the grain husks would potentially have a longer exposure to the wort. Instead, the brewer should use a pure strain of ''[[Lactobacillus]]''. As a result of not using grains to sour the wort, there is less concern of developing [[Butyric Acid]] or [[Isovaleric Acid]] with this method. Even still, lowering the pH of the [[Wort_Souring#How_to_Pre-Acidify|wort to under 4.5 (ideally 4.0 - 4.3)]] will also discourage contaminating bacteria from thriving in the wort during the incubation period. This will also help with head retention <ref>[[Lactobacillus#Foam_Degradation]]</ref>. There is also the option of [[Mixed_Fermentation#Reusing_a_Sour_Yeast_Cake|using a sour yeast cake]] from another sour beer as the bacteria inoculation.
Once cooled to the desired temperature (usually around 90-115°F or 32.2-46°C(see the [[Lactobacillus#Culture_Charts|''Lactobacillus'' culture charts]] for desirable temperature ranges for different ''Lactobacillus'' cultures), 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 than using less than 6 IBU's is a good guideline in general (see the [[Lactobacillus#Culture_Charts|''Lactobacillus'' culture charts]] for tips on hop tolerance for different ''Lactobacillus'' cultures). To achieve a very low IBU wort, 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 1-3 days with the before mentioned target temperature maintained throughout the incubation period (some ''Lactobacillus'' species/strains may continue to produce acidity under lower temperatures, for example ''L. plantarum''). Small temperature fluctuations will not adversely affect the souring process, as long as the temperature stays within the range that is desirable for the particular strain of ''Lactobacillus'', although the brewer should take care not to allow any dust to get sucked into the fermentation vessel due to temperature decreases. During the incubation time as long as ''Lactobacillus'' is the only microbe growing in the wort, the gravity will not drop more than a few points, and the fermentation will be very calm (see [[Lactobacillus#100.25_Lactobacillus_Fermentation|''Lactobacillus'' fermentation]]. 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|pH Meter meter]] throughout this time. If possible, it is advised that the brewer 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.