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===Maintaining a Lactic Acid Bacteria Culture===
It is possible to maintain a ''Lactobacillus'' culture from batch to batch of beer. One method that is common with commercial brewers is to collect an appropriate volume of the soured wort (after souring, but before pitching yeast). Commercial breers brewers will often use a designated corny keg or sanke keg (depending on the colume volume that is required). After souring, the wort a small portion will be transferred using a closed system into the keg. The keg is then refrigerateduntil refrigerated until it is needed for the next batch. Storing the soured wort cold is recommendedfor lengthening the viability of the ''Lactobacillus'' culture while also inhibiting the growth of any potential contaminants, however , the ''Lactobacillus'' might perform differently based on a number of variables such as how long it is stored (longer storage means less viability). Re-pitching might lead to an increase in acid production as well. we We recommend experimenting with this process and finding the right pitching volume/storage time until repeatability can be achieved.
Homebrewers can use a similar process. For a 5 gallon batch of soured wort, collect around 1 liter of wort in a jar before pitching yeast. Keep the culture cold until the next use. Don't seal the jar completely tight in case refermentation occurs in the jar. If the culture is kept for more than a couple of months, then [[Lactobacillus#Starters_and_Pitching_Rate|create a 500 mL starter]] to ensure that the bacteria culture is still viable.
Yeast contamination is a concern when storing soured wort, especially in a sealed vessel such as a keg. If a yeast contamination goes unnoticed, then the keg can become heavily pressurized and potentially dangerous even when stored cold. We recommend regularly checking a keg of soured wort to ensure that over-pressurization does not occur, or use a spunding valveto ensure that over-pressurization does not occur.
==Contamination Concerns==