Changes

'''Wort Souring''' is the process of "[[Mixed Fermentation]] " (in the case of lactic acid bacteria being left alive to co-exist with yeast) or "Sequential Fermentation" (in the case of kettle sours) where lactic acid bacteria, usually ''[[Lactobacillus]]'' (although there are also ''[[Pediococcus]]'' cultures available that work well for this technique), is given a "head start" as it's pitched before the yeast so that it will be able to produce significant amounts of lactic acid before the ''Saccharomyces'' completes the main fermentation. While non-sour beer falls in the range of 3.8-4.6 pH, a final pH between 3.0 and 3.7 is the general target range for the soured wort and also the finished sour beer (although [[Titratable Acidity]] is more accurate for measuring perceived sourness). This is a broadly defined technique and there are many variations on souring wort. These include souring in the primary fermenter, souring in a secondary vessel, or souring in the boil kettle itself ('''kettle souring'''). There are also various methods of inoculating the wort with ''Lactobacillus''. Finally, the brewer has the option of pasteurizing the wort by heating it to kill the ''Lactobacillus'' before adding the yeast for the main fermentation.