Idea for Lacto Fermentation

So I made a sour using Lacto a couple months back and it turned out nice, but I'm wanting to tweak things a bit. Here's my idea... I'm hoping those of you with more experience in this arena can let me know if this would work:

Mash and boil as normal... 6 gallons total.

4 gallons into a 5.5 gallon carboy. Pitch ringwood yeast.

2 gallons into a 3.5 gallon carboy. Pitch lacto.

After a week at proper temps for both carboys, pasteurize the 2 gallons of lacto and combine both batches into a 6.5 gallon carboy.

I guess my area of concern is the fermentation itself. Am I correct in that the lacto isn't actually creating alcohol? Would I therefore not get hardly any ABV after combining? Furthermore, would the package of ringwood be too much for the 4 gallons of wort to handle (i.e. overpitching)??

Thanks!

What you have there looks like it would work. It's pretty similar to what I did with a sour mash/ambient ferment beer a while back. I'd be more worried about a too-small lacto pitch than a too-large ringwood pitch. When you say "proper temp", do you mean 100+ for the lacto? It will thrive there. If not, you might want to give it more than a week, as lacto reproduces more slowly at lower temps.

As far as fermentation products, if you pitch commercial lacto (lactobacillus d.), then yes- you'll only get lactic acid and CO2. If you use bottle dregs, such as Phantome, you'll get a mix of lactic acid producers, some of which can produce alcohol (and other compounds as well).

thanks!

ya, i meant 100+... so good to go there. i was going to pitch the entire 100ml pack of lacto into the 2gal batch.

in terms of fermentation... any suggestions? could i repitch some more ringwood or something after combining the two separate batches? i don't need a huge beer or anything but something in the 3% range at least would be nice.

I just did something similar. I brewed a batch of stout where I tapped off 5 liters of wort after 15 min in the boil (and before any hop additions). This unhopped wort had only Wyeast lacto pitched in. The rest went on for a full boil as normal and that was pitched with Brett L (that portion was 15 liters). I left both to ferment at normal temps (not 100F). The lacto portion sat for nearly five weeks. It developed a really nice acidity both in flavor and aroma.

The interesting thing is that gravity wise the lacto only portion ended really high. I don't have my notes with me right now but I think it only moved 0.010 down. I had hoped for more since I didn't want too high ABV after blending back (and therefore letting the brett L have more to eat). Anyways, the flavor after blending the two portions of stout back together was freaking fantastic. I didn't worry about trying to kill off the lacto because due to the IBU's in the brett portion the lacto will be inhibited.

Brewsader said:

The interesting thing is that gravity wise the lacto only portion ended really high. I don't have my notes with me right now but I think it only moved 0.010 down.

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the specific density of lactic acid is pretty high in proportion to water (1.2) so you probably wouldnt see much of a gravity change, especially with our fairly crude measuring techniques (hydrometers), ideally you would measure pH and see how that changes with time and be able to estimate the lactic acid concentration

ryane said:

the specific density of lactic acid is pretty high in proportion to water (1.2) so you probably wouldnt see much of a gravity change, especially with our fairly crude measuring techniques (hydrometers), ideally you would measure pH and see how that changes with time and be able to estimate the lactic acid concentration

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Hmmm, now I remember reading that. Damn. I didnt check the pH unfortunately. It was the first time I've ever done a separate lacto ferment. I'll have to somehow estimate what may have been left in the lacto portion for the Brett to ferment.