Is mold always visible?

[eva114]

I'm new to brewing kombucha. On day 8 of fermenting my first batch ever i saw green/blue circles and just a little bit of white fuzzy thing. It looked like mold but because i wasn't sure, i just removed it from the jar and tought that if it was mold, it would apper again. Since then scoby looks healty (i think?).

That is my scoby on day 8 of first batch:

Scoby is now not fuzzy at all and first batch tasted ok (again, it's hard to tell, because i'm new with all this, but i liked it), so yesterday, on day 12, i started with second fermentation of that batch and with first fermentation of a new one.

This is how it looks like today, on 1st day of second batch:

Is it possible that scoby is "secretly" contaminated with mold? Is it safe to use?

 

[RPh_Guy]

Mold is allergenic and can produce toxins and carcinogens.

Definitely mold in the first photo.
The dark spots look a little suspect in the second photo, but normally it grows on the surface where there is lots of oxygen. Maybe they were on the surface since it looks like it's been disturbed.

I would dump it and start over.

To prevent mold it should help to loosely cover the jar (CO2 gas needs to escape, so not tightly).

Bummer, but hope this helps.
Welcome to HBT.

 

[eva114]

I think the dark spots are dark because of black tea - yesterday, before i started new batch, there weren't any. It looked pretty much transparent:

The jar is covered with cheesecloth - that's ok, right?

Well, i'll start over, thank you for your help!

 

[RPh_Guy]

The jar is covered with cheesecloth - that's ok, right?

You could cover loosely with the lid, or use a clean towel or washcloth rubber-banded or tied to keep tight.
I know it's exciting to watch but try to avoid opening it frequently
It would also help to fill the jar more.

The better you keep out oxygen, the less chance of mold, and the less vinegar formation can occur.

Good luck!

 

[Yooper]

I use coffee filters with a rubber band around mine.

The SCOBY forms, and covers the entire surface of the liquid, completely to the sides, so that mold can't form. Your SCOBY seems to not do that- Here's one of mine:
This is from the side:

In order to avoid mold and other contamination, the SCOBY should form quickly.

Did you use enough strong starter to get it going initially? Something isn't right when you've got obvious mold, so it should have some troubleshooting to stop it from continuing to happen.

 

[eva114]

I used about 2 cups of starter liquid and 4,5 l of sweet tea - 1 cup came with scoby and i added about 1 cup of bought kombucha. Maybe that was a problem?

 

[Morden2004]

I'm new to brewing kombucha. On day 8 of fermenting my first batch ever i saw green/blue circles and just a little bit of white fuzzy thing. It looked like mold but because i wasn't sure, i just removed it from the jar and tought that if it was mold, it would apper again. Since then scoby looks healty (i think?).

That is my scoby on day 8 of first batch:

Scoby is now not fuzzy at all and first batch tasted ok (again, it's hard to tell, because i'm new with all this, but i liked it), so yesterday, on day 12, i started with second fermentation of that batch and with first fermentation of a new one.

This is how it looks like today, on 1st day of second batch:

Is it possible that scoby is "secretly" contaminated with mold? Is it safe to use?

The dark spots in the second batch photo are the yeast strains. They are usually dark I think because they tend to pull color from the tea. I use organic black Gunpowder tea (loose) and my brews look just like your picture. I have had mold twice from poor management. You need to monitor the pH closely. It should be between 4 and 5 for a safe fermentation.

 

[RPh_Guy]

You need to monitor the pH closely. It should be between 4 and 5 for a safe fermentation.

Do you have science to support this?

Clostridium is by far the most dangerous food contaminant.
PH under 4.5 prevents Clostridium growth. Both components of a SCOBY can quickly lower pH below 4.5.
Oxygen also prevents Clostridium.
Either it's fermenting and the pH is lowered or it's not fermenting and there's oxygen so Clostridium can't grow either way.

Acid generally won't inhibit mold.
Since mold requires plenty of oxygen to grow, all you need to do is deprive it oxygen. A healthy fermentation removes oxygen and then proper handling can avoid introducing oxygen.

Other pathogens are far less likely to contaminate, and are generally inhibited by alcohol and acid created during fermentation. Alcohol production and nutrient depletion help too. It's really a wonderful process

Cheers