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# Store the resulting slurry at refrigeration temperatures. A slight drop in pH may still occur, but this technique should keep the storage solution well above 4.0 pH.
Commercial brewers who are attempting to re-use pure ''Lactobacillus'' cultures for kettle souring will often pull a portion of the soured wort before boiling it. The soured wort with living ''Lactobacillus'' is stored for later use in future batches. Cold storage is probably preferred. This can be difficult to accomplish because the residual sugars in the wort can easily attract a yeast contamination or other contaminations (see [[Lactobacillus#100.25_Lactobacillus_Fermentation|100% Lactobacillus fermentation]]) <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1457254734302736/?comment_id=1457291207632422&comment_tracking=%7B%22tn%22%3A%22R1%22%7D Conversation with Bryan of Sui Generis blog on storing Lactobacillus in wort. 11/02/2016.]</ref>. Storing buffered wort above 4.5 pH anaerobically could provide the potential for botulism toxin formation (see [http://beerandwinejournal.com/botulism/ this Beer and Wine Journal article by Dr. Chris Colby]). Autoclaving, pressure cooking, or [https://en.wikipedia.org/wiki/Tyndallization tyndallizing] the wort before adding the ''Lactobacillus'' culture to it would provide a sterile media free of potential botulism spores <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1447181778643365/?comment_id=1447997755228434&reply_comment_id=1457273457634197&comment_tracking=%7B%22tn%22%3A%22R3%22%7D Conversation with Logan Blancett regarding tyndallization and botulism toxin. 11/02/2016.]</ref>, but may not be a practical process for the brewer. It might be possible to achieve a pH of 4.0-4.5 using CaCO3 (chalk) to buffer the pH in a range that extends the viability of the ''Lactobacillus'', and also makes the wort safe for storage (need ref; amounts of CaCO3 needed).
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