Changes

'''Wort Souring''' is the process of [[Mixed Fermentation]] where lactic acid bacteria (, usually ''[[Lactobacillus]]'', (although there are also ''[[Pediococcus]]'' cultures available that work well for this technique) , is given a "head start", pitched before the yeast so that it will be able to produce significant amounts of lactic acid before the ''Saccharomyces'' completes the main fermentation. This is a broadly defined technique, and there are many variations on souring wort, including . 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.

Many brewers prefer this process over [[Sour Mashing]] because it can be easier to control, and when implemented properly , it produces a clean sour beer in a short amount of time. However, the environment created provides an ideal situation for contaminations, and great care should be taken to prevent contamination of both yeast and spoilage microbes (see [[Wort_Souring#Contamination_Concerns|Contamination Concerns]] below).

The possibility of pasteurizing the soured wort also makes this a good method for making sour beers with a lot of residual malt sweetness (e.g. sour barley wines), and also makes it an attractive process for brewers who are concerned about infection issues in their cold side equipment (equipment that is used post-boil) <ref>[http://sourbeerblog.com/fast-souring-lactobacillus/ Miller, Matt. Dec 20, 2014. "Fast Souring with ''Lactobacillus'' – Best Practices, Sensory, & Science". Sour Beer Blog.]</ref>. When souring wort, some brewers first [[Wort_Souring#How_to_Pre-Acidify|lower the pH of the wort to 4.0-4.3]] before pitching ''Lactobacillus''. This has sometimes been found to help helps the head retention of the beer, and it sometimes helps to protect the wort from contaminating microorganisms. For more information preventing the loss of head retention in sour beers, see the [[Lactobacillus#Foam_Degradation|''Lactobacillus'' page section on Foam Degradation]].