Lacto Brevis vs. Delbruekii

[BigPerm]

I'm a little late to this thread, but the only explanation for your final gravities here is yeast contamination. Lactobacillus (heterofermentative or homofermentative) cannot attenuate to this degree. Even assuming a heterofermentative lactobacillus, this type of metabolism means a single glucose molecule is split into 1 molecule of lactic acid, one molecule of ethanol, and one molecule of CO2. The lacto can't direct output to ethanol production at the exclusion of lactic acid production. Practically speaking, this means that if one actually experienced 75% apparent attenuation with pure lacto, you should have in the neighborhood of 1.75% lactic acid by volume. The link to the Wyeast presentation in this thread shows that Berliners with a pH of 3.0 to 3.3 are .6-.8% lactic acid. A 1.75% lactic acid beer is probably not drinkable and would be under pH 3.0.

You are making some assumptions here that may or may not be correct. You can't (necessarily) assume there will be a 1:1 ratio of EtOH/Lactic acid produced, as fermentation conditions and strain will likely influence that ratio (and feedback inhibition as another noted). For example, the Bruery's Hottenroth is essentially a 100% Lactobacillus fermentation (although there is a small amount of brettanomyces in their, but they contend that it comprises a very small proportion of the microbes.) WLP677 claims 75-85% attenuation. I've never fermented it alone, so I can't comment on that with direct experience.

@oldsock did a 100% lacto experiment awhile back, but it doesn't look like he noted a FG. Maybe he can weigh in here?

 

[Oldsock]

You are making some assumptions here that may or may not be correct. You can't (necessarily) assume there will be a 1:1 ratio of EtOH/Lactic acid produced, as fermentation conditions and strain will likely influence that ratio (and feedback inhibition as another noted). For example, the Bruery's Hottenroth is essentially a 100% Lactobacillus fermentation (although there is a small amount of brettanomyces in their, but they contend that it comprises a very small proportion of the microbes.) WLP677 claims 75-85% attenuation. I've never fermented it alone, so I can't comment on that with direct experience.

@oldsock did a 100% lacto experiment awhile back, but it doesn't look like he noted a FG. Maybe he can weigh in here?

I noted 1.008 after 6 weeks down in the comments. Doubt it ended up much lower.

Haven't found any great sources on what determines lactic acid production in heterofermentative strains. Anecdotally, hops seem to reduce acid production even if they aren't enough to stop fermentation.

 

[Calder]

with lacto it sounds like it is not just sugar dependent but also pH dependent. so, if i'm reading your post correctly, you couldn't just put a small amount of lacto in a lot of sugar and get .4 cells per gram (non-agitated) or 1.4 cells per gram (agitated) like with yeast but you would have to have enough lacto present in that amount of sugar so it can replicate to the count you want before getting down to a 3.8 pH. on the other hand, maybe you don't need as much since you aren't worried about the pitch rate vs flavor profile like with yeast but you still need enough to keep generating acid in a low pH, unfriendly environment where the kill rate is high. That makes it a bit more tricky to calculate both lacto starters as well as pitch rates.

Also, my guess is different strains behave differently so with brevis maybe you get growth and continue to generate acid to a lower pH than other strains. Or not

The more you learn, the more you realize how much more you have to learn.

From what I had read, I didn't think starter size, or even a starter were important, and may even be detrimental to the process, but from what you say, I might have to re-think my position on pitch rates. Got to do some more research.

 

[Dennis]

I pitched L. Brevis in my 1.056 Saison wort (3IBU) @100*F and has been violent with activity since. It has been three days, tonight I will pitch my 1 liter starter(WL568).

 

[Dennis]

So after pulling a sample I have no doubts that L. Brevis could 100% ferment this brew. After three days it is exceptionally clean, tart but not super sour. Amazingly that 3 IBU of Saaz plays out nicely. I could drink this as is all day.

 

[lshaner]

So after pulling a sample I have no doubts that L. Brevis could 100% ferment this brew. After three days it is exceptionally clean, tart but not super sour. Amazingly that 3 IBU of Saaz plays out nicely. I could drink this as is all day.

It's good that you ended up with a product you like, but you had a yeast infection. L. brevis does not create a krausen and it is not capable of complete attenuation of wort.

http://www.milkthefunk.com/wiki/Lactobacillus#100.25_Lactobacillus_Fermentation

 

[Dennis]

It's good that you ended up with a product you like, but you had a yeast infection. L. brevis does not create a krausen and it is not capable of complete attenuation of wort.

http://www.milkthefunk.com/wiki/Lactobacillus#100.25_Lactobacillus_Fermentation

I never said it created a krausen. You misread friend.

 

[Dennis]

As for attenuation, that is why I made/pitched a 1 liter starter of WLP568 Belgian yeast blend after those 3days.

 

[lshaner]

As for attenuation, that is why I made/pitched a 1 liter starter of WLP568 Belgian yeast blend after those 3days.

I guess I'm unclear what you mean by the L. brevis can 100% ferment the brew and that it was violent with activity. Even heterofermentative Lacto like brevis produce essentially invisible quantities of CO2.

 

[ImperialScience]

It seems there is still some disagreement related to the activity of lacto - particularly its ability to attenuate wort and produce large volumes of C02. In my hands, both the strains referenced in this post appeared to be high attenuating and heterofermentive - not what i was expecting based on a limited amount of research. However, this experiment was not designed to test this hypothesis, but rather to compare strain profiles (specifically flavor and acidity without interactions with hops). Basically, i just wanted to make acid beer to blend with and thought i might as well test 2 strains with (supposedly) mechanisms of actions (homo vs heterofermentive).

There is increasing evidence from this post and elsewhere (see milk the funk wiki) that some commercial pitches of lacto have sac and/or other organisms present. This would certainly explain some of the reported behavior of the strains in this post by myself and others. Even very small amounts of other organisms - perhaps not easily detectable under a microscope - could have the ability to reproduce, especially under conditions such as those i used (high temp/lots of food).

to test this hypothesis is not trivial, at least i cannot think of a very good way, but i am not a microbiologist. Perhaps someone can weigh in on this? My initial thought is to take several samples from the pitch in a sterile environment after sanitizing packaging and then again after the same samples post fermentation.

Any suggestions would be appreciated.

Regardless of the outcome, both these strains produce tasty beer and i highly recommend them as a way to quickly produce acidity (at least in the absence of hops).

 

[lshaner]

There is increasing evidence from this post and elsewhere (see milk the funk wiki) that some commercial pitches of lacto have sac and/or other organisms present. This would certainly explain some of the reported behavior of the strains in this post by myself and others. Even very small amounts of other organisms - perhaps not easily detectable under a microscope - could have the ability to reproduce, especially under conditions such as those i used (high temp/lots of food).

to test this hypothesis is not trivial, at least i cannot think of a very good way, but i am not a microbiologist. Perhaps someone can weigh in on this? My initial thought is to take several samples from the pitch in a sterile environment after sanitizing packaging and then again after the same samples post fermentation.

Any suggestions would be appreciated.

Regardless of the outcome, both these strains produce tasty beer and i highly recommend them as a way to quickly produce acidity (at least in the absence of hops).

Post-fermentation is very easy to test if you have access to or know someone with access to a microscope. If you have krausen development or see a lot of CO2 off-gassing, yeast will be easily visible under the microscope.

Even if a commercial container is infected with yeast, it may or may not be visible under the microscope (though more often than not, I have been able to see yeast under the scope straight from the container). The more sure-fire way to test directly from the commercial package would be to plate a 0.5-1 mL sample on a nutrient agar plate containing an antibiotic such as ampicillin. This will kill the bacteria but allow yeast to grow.

 

[dantheman13]

There have been multiple reports of finding yeast in WL bacteria vials when looked at under a microscope on MTF. I'd say we've seen these reports now for about a year or so, and it seems to offer a good explanation for what would otherwise seem to be biologically impossible. Lance Shaner and others have done a lot to show that this is the case. Additionally, WLP677 is "delbruekii", which is not a heterofermentative species. It is either mislabeled, or WL is incorrect about it being heterofermentative. Regardless of that, as Lance has said, Lacto does not produce a yeast-like fermentation. We recently had Kara Taylor comment on the issue as well in MTF, and she said that once they move to the new PurePitch tech for bacteria, the issue should be solved (she said the problem is on their packaging line).

As has been mentioned in this thread, most Lactobacillus scientific studies have not been in a wort/beer environment. Most of it is in cheese or other fermented products, or biotech type stuff. More recently, however, a group of researchers from Belgium looked at flavor development of Lactobacillus in wort fermented beverages. In a presentation, one of the researchers (an expert in Lactobacillus) noted that "Lactobacillus did not ferment more than 0.5°P regardless of starting gravity". When asked why at the end of the presentation, the researcher said she did not know for sure, but suspected that Lactobacillus inhibited themselves and did not need much sugar in order to max out their growth. See this section on the MTF wiki, along with the video: http://www.milkthefunk.com/wiki/Lactobacillus#100.25_Lactobacillus_Fermentation

 

[bigdee4933]

Brevis straight from the package.

 

[Hommel]

can you change the focus? those rod shaped small things are hard to see behind those larger round things.

 

[Agate]

can you change the focus? those rod shaped small things are hard to see behind those larger round things.

I'm sorry, but THAT was funny!