Changes

After the production of the wort, but before pitching the culture of ''Lactobacillus'', some brewers like to slightly lower the pH of the wort with food grade lactic acid (available at homebrew stores) or phosphoric acid before adding the ''Lactobacillus''. This has several benefits, such as discouraging unwanted microbes that may have accidentally been introduced into the wort, and helping to prevent [[Lactobacillus#Foam_Degradation|''Lactobacillus'' foam degradation]]. The idea is to get the wort down to a pH of 4.0 - 4.4 before adding ''Lactobacillus''.  There currently is no formula for how much lactic acid to add to a volume of wort due to the different buffering capacities of wort; water chemistry spreadsheets and formulas geared towards mash pH adjustments may not be accurate for wort pH adjustments since wort does not contain grain material <ref>[http://www.mbaa.com/districts/Northwest/Events/Documents/Study%20in%20the%20Practical%20Use%20of%20Lactic%20Acid%20Bacteria.pdf A Study in the Practical Use of Lactic Acid Bacteria. Greg Doss from Wyeast Laboratories Inc. 2014.]</ref>. Water chemistry spreadsheets and formulas geared towards mash pH adjustments may not be accurate for wort pH adjustments since wort does not contain grain material, however there has been at least one report on MTF that [https://sites.google.com/site/brunwater/ Bru'n Water] can accurately determine how much lactic acid is needed to lower a wort's pH, but using however this claim requires further investigation. We encourage readers to experiment with water chemistry calculators to see if they can accurate predict wort pH adjustments <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1244954842199394/?comment_id=1245053585522853&comment_tracking=%7B%22tn%22%3A%22R%22%7D MTF Thread with Landon Ortiz. 03/03/2016.]</ref>.  Adjusting the pH of wort can be done fairly easily by taking a trial and error approach. Using 1 mL of 88% lactic acid per .1 shift in pH for 5 gallons of wort is a good starting measurement. As an example, say that 5 gallons of wort has a pH of 5.0 just before pitching the ''Lacto''. Begin by adding 5 mL of food grade lactic acid to the wort for a target of 4.5 pH. Stir gently, then take another pH reading. Continue to add 1-2 mL of lactic acid until the wort has the desired pH. Once the desired pH is reached, pitch the ''Lacto'' culture. This small amount of lactic acid shouldn't have much of an impact on flavor.