KNF: Supersaturated LABs gone bad?

Hello RIU.

Made a batch of LABs.
Kept one part in a jar inside my refrigerator, and decided to take another part and supersature it with equal volume of sugar.

Checked the supersatured LABs and found a layer of some kind of foam/mold on top. Smell wasn't bad. Strong but not bad. This was a few days ago.

Today i checked it back, and foam was a little bit bigger and smell pretty much stronger...it smelled like acetone.

Here's a pic of the foam a few days ago.

The fact it smells like acetone or something tells me that you may have a yeast activity going on. Did you pH it before adding all that sugar? If the initial LAB worked properly, you should expect a pH of about 3.5%, certainly not over 4%. And you should get be able to reach that level of ferment without added sugar.

Did you use a commercial LAB inoculant of some sort, or rely on natural sources? I've made LAB concoctions for decades from natural wild bacteria, but it's damn difficult to do without a 2.5% to 3% salt by weight of material and solution. LABs tolerate salt much better than most other common bacteria and thus are able to dominate quickly. Without the salt (which obviously you can't feed to your plants) brewing LABs from wild bacteria is hard because all sorts of things will compete with each other.

During brewing, avoid opening the container for nothing and keep it under airlock at all times to maintain anaerobic conditions. Any oxygen on the surface of your substrate will allow things to compete that you likely don't want to grow. You only want CO2 in there. When pH reaches your target within a few days of starting it, it's done and further brewing or additions will not help them. Time to use for whatever purpose you intend.

I just bottled up my own LABs for human consumption today - half a gallon of my version of "Franks Hot Sauce". It tastes exactly the same, except instead of $4 for a little bottle, the half gallon cost me less than $1 to make. Yeah I'm cheap, and we do go through a lot of hot sauce here. Lol

I made the LAB following the KNF recipe/steps, it looks like this:

1. Put rice water in a recipient and wait 3-5 days
2. Dilute the rice water with milk, 1:10 ratio
3. Within 3-7 more days you can see that the culture has now two fractions, solid and liquid. LABs are on the liquid fraction.



A few days later after separating solid from liquid fraction, it looked like the process continued, like it was forming curds again. That's when i decided two things:
1. Put a part of the culured LABs on the refrigerator, which stopped the process.
2. Supersature with sugar another sample. I read about this in a forum. And that's the one that has the acetone smell.

What type of sugar was used? I believe what you are attempting to achieve is done using brown sugar from the few clips I've watched. Not sure it matters but that's one difference that may explain your results.

JHake said:

I made the LAB following the KNF recipe/steps, it looks like this:

1. Put rice water in a recipient and wait 3-5 days
2. Dilute the rice water with milk, 1:10 ratio
3. Within 3-7 more days you can see that the culture has now two fractions, solid and liquid. LABs are on the liquid fraction.

View attachment 4908665

https://www.ctahr.hawaii.edu/oc/freepubs/pdf/sa-8.pdf

A few days later after separating solid from liquid fraction, it looked like the process continued, like it was forming curds again. That's when i decided two things:
1. Put a part of the culured LABs on the refrigerator, which stopped the process.
2. Supersature with sugar another sample. I read about this in a forum. And that's the one that has the acetone smell.

Click to expand...

Have you ever thought of testing the pH of your ferment? I do it when I need to ensure that lactic acid bacteria have dominated and are thriving. When I see the bubbles in the airlock every now and then, I know it's okay. I would imagine that rice would invite a lot of yeast. So you'll see bubbling if that happens too. But you won't see a big drop in pH with yeast, just a very alcohol/chemical smell or taste. It's the pH that matters. It should go pretty damn quickly below 4.0. That should show up in a relative way in even the cheapest Amazon ph meters. Lol

Will check the pH then. I've made a few KNF inputs, so will check them all out and post the results here.