Selectively growing lactobacillus from sour dregs

[EvilFrog]

I would like to grow up to a large volume lacto starter to have on hand for blending/souring beers. The plan is for it to have mostly just a strong lactic acid character to it (I don't want it to have noticeable brett or other flavors). This would be the kind of thing I could use to blend with a low gravity wheat beer to produce a BW-like product.

If at all possible I would like to use the lactobacillus from some commercial sour dregs I have been saving. The issues there are immediately obvious. If I just pitch the dregs into starter wort and start stepping up in volume, I am going to be growing up brett, saccharomyces, pedio and maybe even acetobacter as well. I guess I am OK with the pediococcus since I am looking for lactic acid production but I want to leave the rest of those guys behind.

Really, I will just be satisfied if I can selectively grow up the lactobacillus so that it completely dominates its competitors. Tell me if this sounds like it could work:

* purge the starter flask with CO2 and keep under an airlock
* no stir plate
* try to keep the temps elevated (around 100F)
* starter wort will be just water and lactose, no malt (or nutrient?)

The thinking is that I am creating an environment that is inhospitable to the creatures I am trying to reduce and beneficial for the lactic acid producers. By, Eliminating the O2 this should inhibit yeast growth and acetobacter activity. The lactose feeding is what I am kind of thinking might have one of the largest selective influences. The lactose should only be a decent food source for the bugs I want to grow right?

If this process is repeated and stepped up each time, would the lactobacillus population completely outgrow the others? Could I then switch to DME for feeding the starter?

Yes, I realize that I could just purchase an already isolated lacto culture but where is the fun in that?

Ideas? Suggestions? Criticisms? Personal attacks?

[BarefootLion]

Personal attacks?

You Smell and no one likes you...

Why not just grab some extra grain brew up your starter then pitch some of the grain into it. Lacto loves to hang out on grain.
My LHBS was just showing me an Old ale that was mashed as something else until he ended up with no time to actually boil..a week later was all full of lacto. Smelled something like feet, leather and cheese...yum.

[EvilFrog]

Personal attacks?

You Smell and no one likes you...

Why not just grab some extra grain brew up your starter then pitch some of the grain into it. Lacto loves to hang out on grain.
My LHBS was just showing me an Old ale that was mashed as something else until he ended up with no time to actually boil..a week later was all full of lacto. Smelled something like feet, leather and cheese...yum.

You are right, I might be due for a shower. Think that will help with the people not liking me part?

Rational Answer:
I want to avoid the other wild enteric bacteria present on the grain. 'feet, leather and cheese' are not welcome at this party. It would be nice to always have a decent volume of clean lactic starter to sour a beer in a controlled way and then just top the starter back with fresh wort. This is going to be a long-lived culture, so I don't want all the other funk there.

Irrational Answer:
I kind of enjoy the idea that the bacteria I will be growing has a pedigree of sorts from some of my favorite commercial beers.

[Elbone]

Seems to me you'd have to take the dregs, plate it out on agar, try to select a pure colony of lactobacillus and culture it up. Of course you'd have to learn to recognize what lactobacillus looks like on a plate but I imagine there are plenty of pictures online as it is a common beer-spoilage bug.

[EvilFrog]

Seems to me you'd have to take the dregs, plate it out on agar, try to select a pure colony of lactobacillus and culture it up. Of course you'd have to learn to recognize what lactobacillus looks like on a plate but I imagine there are plenty of pictures online as it is a common beer-spoilage bug.

Yeah. That sounds a little bit too much like the 'right' way to do it. I would certainly like to have the skills, knowledge and equipment to do such a thing eventually. Presently, I have none of the above. I have not gotten to the yeast lab section of the Yeast Book yet. Maybe I will get inspired when I do! For the time being, I was wondering if this might be an alternative workable solution.

[brewinhard]

Your best bet is to use a commercial lactobacillus (I prefer Wyeast). You will want to use malt as a medium for growth. The problem with culturing lacto over long periods of time is that the lactic acid they produce actually will deter their growth and eventually stop them. They are a very weak bacteria. Do not use any hops either when making your starter. If you wanted to do something like this I would recommend brewing an actual Berliner weisse with a lacto starter and simply let that age for 6+ mos until you have a lactic sour product to blend in with other beers in the future.

[EvilFrog]

The problem with culturing lacto over long periods of time is that the lactic acid they produce actually will deter their growth and eventually stop them. They are a very weak bacteria.

Good to know.

I am guessing they stop because they exceed their acid tolerance at a particular pH. Hopefully this happens way before they start reaching star san solution pH levels and actually kill themselves off right? If their health at peak acid level has not been compromised, could I just rack off what I need for blending and then top off again with fresh wort and expect the bugs to go back to work again? That is what I meant by 'long-lived'. I can't expect this cycle to last forever but do you suppose I could keep a 5 gallon carboy going this way (decanting half at a time and refilling with new wort)? Could I get away with doing this 5 or more times?

[brewinhard]

Not sure about 5 or more times, but I do think it is reasonable to think that you could decant/rack and add fresh wort for the lacto to keep working on. Over time you may need to add a buffer to the wort so the lacto can remain healthy enough to properly ferment. If you are interested in this you should check out the forum on the BBB (Burgundian Babble Belt) as there are some very knowledgeable guys with specific data on this.