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None of the cultures, whether heterofermentative or homofermentative (all were heterofermentative), produced a significant gravity drop. None produced a krausen or obvious CO2 evolution. All samples were sent off to be tested for alcohol levels using the Anton Paar Alcolyzer test. All strains showed some alcohol production, indicating [[Lactobacillus#Types_of_Metabolism|heterolactic fermentation]]. The wort was fermented with foil covering the flasks, so it was not an anaerobic environment <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1114207325274147/ Conversation with Lance Shaner on MTF regarding his 100% Lacto Fermentation results. 7/21/2015.]</ref>. Note that the pH readings of this test correspond with the results of [[Lactobacillus#Commercially_available_Lactobacillus_strains_and_their_pH_change_over_time|Matt Humbard's pH tests with ''Lacto'']].
===Biological Explanations=======Bryan Heit's Biology Explanation====
"This is what I would have expected - those claims of complete attenuation always rubbed me the wrong way, and from a scientific point of view, appeared impossible. pH will (eventually) inhibit even the most acid-tolerant of bacteria. Even if the bug is capable of protecting itself from the degradative nature of acids (which many can), at some point the concentration of protons (acid "atoms") will block the bacteria's proton motive force, which is used to "pump" molecules into bacteria (and in the case of some bacteria, to generate energy). Once the proton motive force is gone, the bacteria is effectively dead.
Bacteria setup a proton motive force by pumping protons out of their cytosol, into the extracellular space. This acidifies the extracellular space and alkinalyzes the cytosol. The energy of this gradient can then be used to "force" other molecules into the cell - e.g. ''Lactobacillus'' uses this to collect amino acids and DNA for growth and replication. However, the more acidic the environment, the more energy is required to pump additional protons out of the cell. The ability of cells to do this is finite; the theoretical maximum "pump force" that can be exerted is equal to the energy of hydrolysis of one ATP (energy molecule); roughly -31 kJ/mol. The theoretical max acidity that will work against is 1.2, but in reality these pumps are generally less than 30% efficient, so for most species pumps fail at pH's above 3.0. Most ''Lactobacillus'' crap out somewhere around 3.2 to 3.0. The pH of a fully attenuated 1.040 wort would be between 1.9 and 2.4 (ignoring buffering effects), depending on whether the ''Lactobacillus'' was homo or heterofermentive. So the claim that ''Lactobacillus'' can completely ferment wort doesn't seem to be biologically plausible." - Comments by [http://suigenerisbrewing.blogspot.com/ Bryan Heit of Sui Generis Blog] <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1114207325274147/?comment_id=1114540208574192&offset=0&total_comments=81&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Conversation with Bryan Heit on 100% lacto fermentation. 7/22/2015.]</ref>
====Elke Arendt====
Elde Arendt, a brewing scientist that specializes in ''Lactobacillus'' presented her work at the Belgian Brewing Conference 2015. In it she explained that LAB will only ferment 0.5°P of wort regardless of the gravity of that wort. When asked at the end of the presentation why ''Lacto'' only ferments 0.5°P, considering that ''Lacto'' ferments maltose and there is plenty of maltose in wort, Arendt responded that she believes that the bacteria reaches max cell density in the wort with relatively little sugar requirements (~16 mins in and ~25 mins in):
<youtube>9a-ZpF2LDm8</youtube>
==See Also==
===Additional Articles on MTF Wiki===