What’s the lowest you’ve seen Lacto get

[couchsending]

I should probably ask this on MTF but I refuse to join Facebook so here we go.

What’s the lowest anyone has seen Lacto go?

I took some final runnings about a week ago with the intention of making some Sauergut to use as a pH adjustment addition to a lager I’m making today.

1.030, no hops.
Wyeast Lacto Buchneri
1200 or so ML
Filled it right up to the top of an Erlenmeyer flask and put an airlock on. Stuck it in an interior closet. House is basically at 68 all the time. 7 or 8 days later I pull it out and measure the pH and it’s 2.95!! WTF? I’ve seen Brevis get to maybe 3.1. But this strain isn’t really supposed to get that low I thought and especially at room temp...

There’s no acetic character. It just smells rather wort like but it actually tastes awesome. Like sour candy.

I was really surprised (and kinda bummed) to see it that low.

Anyone else seen this?

 

[RPh_Guy]

Why would you be bummed?

My understanding is that the pH of sauergut isn't important for it's usage. You should do an acid titration to determine the percentage of lactic acid (should be 1-2%) so that you know how much to use.

I have had my Lacto culture get down to 3.08 in a kettle sour. I tend to question results under 3.0 as possible user error with the pH meter (or calibration solutions). My 3.08 was when I was still pretty new so that may also have been error in my part; I haven't had it get that low since then.

A pH 2.95 is within the realm of possibility for some strains, but not from WY5335 from anything I've ever seen. WY5335 would probably have a hard time getting under 4.0 at 68°F even after a week. 3.95 I would believe.
http://www.milkthefunk.com/wiki/Lactobacillus#pH_change_at_86.C2.B0F

 

[couchsending]

Bummed because it means I have to add less of the sauergut. Hoping for a bigger flavor impact from a larger addition.

Milwaukee pH meter MW-102

Calibrated before every brew day. Calibrated it twice after with different solutions. 2.95 every time.

 

[RPh_Guy]

Interesting.

You can add more at flame out.

You did an acid titration so you know how much to add to the mash?

 

[couchsending]

Interesting.

You can add more at flame out.

You did an acid titration so you know how much to add to the mash?

I didn’t do a titration... I’ve done it enough where I roughly know how much based on pH. Added some and hit 5.5. Added a bit more and hit my target of 5.4.

I add it in the mash and at KO always. The KO addition is what I was bummed about as IMHO that’s what adds the most flavor. It ended up not being too bad and hit my KO pH of 5.0 with 2 additions. Just less than I was hoping to add.

 

[RPh_Guy]

I suppose the only advice I could give is that you can keep a SG "reactor" going by feeding it periodically, and it will be very consistent with regard to pH and acid content.

Do you use the same culture every time? WY5335 hitting that low seems extremely unlikely. I'm thinking it had some kind of contaminant, especially if your pH meter is reading other things within reason.

 

[couchsending]

I’ve really only used a Brevis strain in the past for this purpose. It’s a totally different Erlenmeyer flask than what I’ve used in the past. Boiled for 10 minutes, etc.

It makes zero sense to me. Never ever thought it would get that low. It was incredibly sour but with no off flavors and nothing approaching acetic.

 

[RPh_Guy]

Maybe the bacteria culture got contaminated at Wyeast with a strain that's actually good

 

[goodolarchie]

Outside of kettle souring, I had a lacto strain (guessing brevis) in a house blend get a little out of balance around gen 4 or 5, brought ~8IBU wort from 5.35 to 3.40 in 3 days at 72º, and leveled out at 3.24 a couple weeks later (Apera PH60). That's the lowest I've seen outside of ideal lacto conditions.

Never did a TTA because the acid profile is terrible, it's about as sharp as adding several tablespoons of 88% lactic acid to a finished beer. I kept some as blending stock but odds are it will get dumped unless it balances out over time. I would hate to see what it could do to low/no hopped wort at higher temperature. I don't use that blend anymore without reaching 15+ IBU.

 

[Bilsch]

Lacto is less acid tolerant at higher temperatures so possibly because you soured at room temp might be how it got lower then you expected.

 

[goodolarchie]

Lacto is less acid tolerant at higher temperatures so possibly because you soured at room temp might be how it got lower then you expected.

Interesting theory, that's possible. I don't want to derail the thread toward my situation, but my theory is that my relatively low IBU (~2-4 IBU) wort re-propagations of previous generations favored the Lacto in the blend, put it out of proportion to the Sacch/Brett, and so it was able to produce a ton of lactic acid in the first 36 hours, before the Sacch could really lower the pH on its own and slow the lactic production. It would be tantamount be like staggering a giant active lacto pitch on brew day, then a smaller sacch pitch the next day.

To compensate I've upped the IBUs on both my base recipe when using this blend, and my canned wort that I use to prop up the next generation of house blend for faster, balanced souring.

 

[couchsending]

Yeah again I have a really hard time explaining what happened. I filled the same flask again with last runnings and we’ll see if it happens again.

It was definitely sour but not unpleasant at all. I’ve only used planatrum and Brevis in the past. This seemed to have very little aroma (again smell was very wort like, but no off aromas that I could detect) as compared to the other strains I’ve used.

There was definitely a decent amount of Co2 production going on when I pulled it out to use it. Not krausen or anything but plenty of medium size bubbles rising to the surface.

 

[RPh_Guy]

Bubbling indicates yeast fermentation.

 

[couchsending]

Not necessarily... this lacto can produce Co2.

 

[RPh_Guy]

Not necessarily... this lacto can produce Co2.

Hmm you're right.

I have have wanted to confirm with a hydrometer that it wasn't contaminated with yeast though.