r/Kombucha Sep 18 '21

what's wrong!? Is it mold? Is it normal? What's growing in your kombucha? Start here!

465 Upvotes

Welcome to r/Kombucha! If you're wondering what's growing on your kombucha and if it's normal, you've come to the right place.

Please review this information before posting a picture of your batch to the subreddit.

TL;DR:

  • Dry + fuzzy on the surface of the liquid/pellicle/SCOBY is most likely mold: mold pics https://imgur.com/a/SzhysHi
  • Geometric growths or wrinkly patterns on the surface of the liquid/pellicle/SCOBY could be kahm yeast: kahm pics https://imgur.com/a/XlnO7Ox
  • Anything else and anything under the liquid level is most likely normal: normal pics https://imgur.com/a/HJaENDv
  • If you're not sure, wait a few more days: mold or kahm will get more obvious as they grow, normal will stay about the same or form into new pellicle/SCOBY
  • If the kombucha is already bottled for carbonation (commonly called second ferment or 2F), mold/kahm is very unlikely due to the high acidity and lack of oxygen access.
  • Always use at least 2 cups of starter per gallon (125ml/L) when making kombucha to acidify the batch: high acidity (pH < 4.6) protects the kombucha from mold and kahm.
  • Read our getting started guide for brewing tips: https://www.reddit.com/r/kombucha/wiki/how_to_start

Terminology: in this guide, "pellicle/SCOBY" refers to the rubbery blob that forms at the surface of a batch of kombucha. SCOBY stands for "symbiotic culture of bacteria and yeast", and those bacteria + yeast are found both in the liquid kombucha and in the solid rubbery blob. The rubbery blob's more accurate scientific name is "pellicle": it's a biofilm/mat of bacterial cellulose secreted by and connected to the bacteria forming it (some yeast also live in the pellicle). Culturally, however, the term "SCOBY" widely refers to the pellicle so this guide uses both terms.

Read more about pellicles here:

Diagnostic Quiz

1 ) Is the growth/odd thing on the top surface (exposed to air) of the liquid kombucha or existing pellicle/SCOBY?

  • Yes - go to 2
  • No - go to 8

2 ) Is the kombucha already bottled for carbonation (commonly called second ferment or 2F)?

  • Yes - likely pellicle/SCOBY growth (it can happen in 2F!) or a yeast cluster. Mold/kahm are extremely rare in 2F due to the high acidity (pH <4.2) and lack of oxygen access (required for mold to grow). Booch on!
  • No - go to 3

3 ) Is the growth dry and fuzzy looking with white or green color, and/or with black spores growing out of it?

  • Yes - likely mold. Go to Mold section for pictures.
  • No - go to 4

4 ) Is the growth a wrinkly or geometric pattern, very rough patterned surface, or very large air-y bubbles that cover large areas of the surface?

  • Yes - likely kahm yeast. Go to Kahm section for pictures.
  • No - go to 5

5 ) Is the growth one of: white/translucent + wet, disconnected oily/patchy sections, or a thin film with bubbles trapped underneath?

  • Yes - likely normal pellicle/SCOBY growth. Go to Normal section for pictures.
  • No - go to 6

6 ) Is the growth flat, leathery, and brown?

  • Yes - likely a dried out pellicle/SCOBY area. Go to Normal section for pictures.
  • No - go to 7

7 ) Is the the growth brown/black, wet, and partially/completely surrounded by pellicle/SCOBY?

  • Yes - likely a yeast cluster. Go to Normal section for pictures.
  • No - probably normal, but review all Normal, Kahm, and Mold pictures to be safe.

8 ) Is the growth/odd thing completely submerged in liquid?

  • Yes - likely yeast. Yeast can form dark brown clumps in the liquid or on the pellicle/SCOBY, or alien-like formations suspended in the liquid. Mold and kahm cannot grow beneath the surface of the liquid without also showing on the surface exposed to air. Go to Normal section for pictures.
  • No - go to 2

Normal

Gallery of normal kombucha: https://imgur.com/a/HJaENDv

Pellicles/SCOBYs have a ton of natural variation. A normal pellicle/SCOBY should look wet, tan/white/translucent, and be mostly smooth (some bumps are normal). There may also be wet brown/black yeast blobs that attach to the liquid side of the pellicle/SCOBY, get absorbed into the pellicle/SCOBY, or float around inside the liquid.

Mold

Gallery of mold: https://imgur.com/a/SzhysHi

Mold occurs when the kombucha is not acidic enough (pH < 4.6) to prevent mold organisms from growing. Other factors that make mold more likely are unsanitary conditions and cold brewing temperatures (<65F/18C).

If there is mold on your batch:

  • You must throw away everything (liquid + pellicle/SCOBY) and start from scratch with fresh starter tea. By the time mold is visible on the surface of the brew, it has already contaminated the entire batch.
  • Sanitize the vessel, cloth cover, and any utensils used in brewing with a homebrew sanitizing solution (StarSan, OneStep, SaniClean, potassium metabisulfite, etc) or throughly wash with soap + hot water followed by a pasteurized distilled vinegar rinse (no raw vinegar, which contains live microbe cultures).

To prevent mold, the most important thing is to use at least 2 cups of starter tea per 1 gallon of kombucha (125ml per L) to acidify the batch. Starter tea is mature kombucha: either from a previous batch (yours or a friend's), from a SCOBY hotel, or from raw/unflavored/unpasteurized commercial kombucha such as GTs or Health-Ade.

This amount of starter tea is a good rule of thumb for safe acidity: if you have a pH meter or strips, check that the starting pH is <4.6. Another important factor is maintaining clean/sanitary brewing practices: however, because kombucha is an open air ferment some mold organisms may get in even with a cloth cover, which is why acidity is also important.

Kahm Yeast

Gallery of kahm: https://imgur.com/a/XlnO7Ox

“Kahm” is a generic term for many species of usually non-harmful but also non-desirable wild yeast that can take hold in kombucha (outcompete the kombucha culture) and appear as surface growths on the the pellicle/SCOBY. Kahm often looks geometric or wrinkly vs the smooth/bumpy normal pellicle/SCOBY.

See this excellent writeup about the science of kahm yeast from u/daileta in r/fermentation: https://www.reddit.com/r/fermentation/comments/ytg2vy/kahm_down/ Their post is focused on lacto fermented vegetables (not kombucha) but is worth a read.

Kahm itself isn’t usually dangerous, but to quote our resident food microbiologist u/Albino_Echidna: “Kahm is a term used to lump a whole bunch of unwanted yeasts together, all of which are indicative of an unsafe fermentation environment. Kahm growth is indicative of a fermentation gone wrong. 'Kahm' itself isn’t harmful, but it is a warning sign that your environment wasn’t quite right and will be at higher risk of pathogenic growth as a result."

If your batch has kahm, it is up to you whether to toss + sanitize + start over with fresh starter kombucha or to try to scrape off the kahm from the surface and continue brewing. It is always safest to toss and restart - see the instructions in the Mold section.

To help prevent kahm, use at least 2 cups of starter tea per 1 gallon of kombucha (125ml per L) to strongly establish the kombucha culture and acidify the batch. Kahm may also be related to unsanitary conditions, high brewing temperature (>85F/30C), or oversteeping tea (>1hr, but may vary).

Further reading: https://www.reddit.com/r/kombucha/wiki/whats_wrong

If you still aren’t sure after comparing your batch to the pictures here, please make a post and ask!


r/Kombucha 1d ago

r/Kombucha Weekend Open Discussion: What Are You Drinking/Brewing? (April 05, 2025)

2 Upvotes

This is a casual space for the r/Kombucha community to hang out: feel free to post about anything related to kombucha, brewing, or life in general.

Show off your latest batch, what you have in progress, or anything that you're thinking about trying.

Questions from new brewers are especially welcome!


r/Kombucha 1h ago

A success!

Enable HLS to view with audio, or disable this notification

Upvotes

Hey, everyone! My family and I made Mango-Pineapple Kombucha (7 days 1F, 4 days 2F). Really happy about the outcome! The fruit combination and the fizz was amazing. Happy brewing!


r/Kombucha 2h ago

My fresh batch

Thumbnail
gallery
3 Upvotes

r/Kombucha 1d ago

reading Kombucha anatomy

Post image
303 Upvotes

I was researching on kombucha and found this really helpful diagram - https://thekombu.com/blogs/journal/anatomy-of-kombucha


r/Kombucha 2h ago

flavor Recipes for tamarind kombucha?

3 Upvotes

I love the flavor of tamarind and I think it could pair really well with kombucha!
Do you have any recipes? Especially using tamarind pulp (paste is harder to find)

PS: Generally, I like my kombucha to be quite sour and not too fizzy :)


r/Kombucha 2h ago

what's wrong!? Is my kombucha moldy?

Thumbnail
gallery
3 Upvotes

This is my first ever time brewing kombucha. I fermented it on March 21st and this is what it looks like today. I will add that up until last night/this morning my original scoby was at the bottom of the container. It just recently floated up top. Did I do something wrong? Why does the scoby look like that?


r/Kombucha 2h ago

Kombucha flavors

3 Upvotes

What are the best kombucha flavors you have done. I want to do hibiscus cinnamon, lavender with something, raspberry, chai, coffee kombucha. Any advice on this?


r/Kombucha 4h ago

question 2F question

3 Upvotes

How can i add to my kombucha ginger like i need to blend it add sugar and something more or am i wrong ?

And secod question can i add achohol to my 2f or will it just kill the bacteria ?


r/Kombucha 2h ago

question Does this look ok to you folks ?

Thumbnail
gallery
2 Upvotes

I don’t see any white spores or patches , everything looks shiny but I see bubbles trapped inside white spots


r/Kombucha 5m ago

what's wrong!? For anyone who doesn’t recognise mold😅

Post image
Upvotes

I let this sit for too long while I was away, allready expected it to go bad. PS: always be carefull if you have this, inhaling the spores can be really harmfull. Also still having mold remnants in your container can ruin your next batch, always clean with hot (boiling water). Goodluck everyone.


r/Kombucha 25m ago

Best place to buy a SCOBY online?

Upvotes

Hi! I brewed kombucha back in 2020/2021 and loved it. Unfortunately, I lost custody of my SCOBY during a breakup. I had gotten it from a friend, so I've never actually bought one. I live in the middle of nowhere, so probably ~200 miles from anywhere that might sell them. I've looked around online a bit and there seems to be a lot of options, so I'm wondering where the best place would be. I'd prefer buying from a female or POC owned small business if at all possible. TIA!


r/Kombucha 16h ago

Do you filter your yeast out when bottling?

Post image
16 Upvotes

I go back and forth. This batch seems way more yeasty than normal so just for texture I’d probably filter this one when bottling. Just wanted to see what everyone else normally does.


r/Kombucha 5h ago

question Should I use honey during the second or first fermentation?

2 Upvotes

Hi folks, I was wondering if it is a good idea to use honey as a sugar substitute for the first fermentation or if it is better to add it as a flavour during the second fermentation.

Since it has a high sugar content, I don't know which option would be best.

Thanks!


r/Kombucha 1h ago

Free (and clean) bottles in Austin, TX

Upvotes

Anyone in the Austin area need some f2 bottles? I have way more of these than I’ll ever use. They’ll need seals. Free to a good home!


r/Kombucha 5h ago

question First timer here

1 Upvotes

Hello all

EDIT Apparently I can't upload pic when editing, so it's in the comment section.

I've looked through the Community Guidelines but haven't found a picture that resembles what I have in my glass vessel.

So, first time kombucha fermentator (?) here, and I got a small, flat piece of SCOBY from a friend with starter fluid. I steeped tea, sugar and into a glass jar along with this scoby. I did it Saturday evening last week and a week later today I opened it up and saw this. I have had it in the living room with a towel over and rubber band around the mouth of the jar.

Is this normal? I can't spot any mold on top - the black things are from loose tea; learned my lesson and will use tea bag for the loose tea - AND not using Earl Grey with bergamotte. You live you learn.

But should I start over again? Don't want to bottle mold and ruin a batch.

The smell is very vinegary with some sweetness to it - smell wise I would wait a few more days until it's more in balance. I have not tasted it yet so can't say anything about that balance

What do you say? Is this the SCOBY adjusting? Should I be patient and wait a few more days to see if mold or kahm will form?

Recipe: 1 liter water, 20 gr. black tea, 100 gr white cane sugar


r/Kombucha 6h ago

Grayish blob on the bottom side of my scoby

Post image
1 Upvotes

Greetings, all. Would any experts be kind enough to tell me if my scoby has become corrupted? No fuzz, or blue/green coloring. Just a kind of brownish, gray blob. Thank you for your time


r/Kombucha 21h ago

First batch ever!

Post image
14 Upvotes

I’ve tried to make kombucha for the first time in my live with violet and yellow oolong teas. I also decided that I love the flavour too much to make only a few bottles, so I made around 20 literes. (didn’t had enough bottles for the project so the rest I couldn’t get into them I just drink straight out of my fermentation jar, thank God for jars with the tap!!)


r/Kombucha 7h ago

question My Amazon SCOBY Disaster & Recovery Attempt! Advice Nee

0 Upvotes

I've got a perplexing kombucha situation and desperately need some experienced advice.

About a month ago, I bought a SCOBY online (Amazon). I followed the instructions and brewed my sweet tea, adding the starter liquid and the pellicle. After two weeks, I was expecting some tang, but the tea was still overwhelmingly sweet. I also noticed the pellicle had sunk to the bottom, which seemed odd based on my previous brewing experience.

Then came the concerning part: when I fished out the original Amazon SCOBY, it was really dark in color. It didn't look healthy at all, and frankly, I was worried it had died or something was wrong, so I ended up throwing it away.

Thinking the batch might still be salvageable, I took a healthy-looking pellicle layer from another batch that was fermenting perfectly and dropped it into the questionable (still very sweet) tea.

Now, it's been about two weeks since I added the new pellicle. I'm seeing the pellicle floating on top and even forming new layers, which is what I'd expect from a healthy fermentation.

However, I'm really worried about the initial two weeks where the original (dark, sunken) SCOBY was in the sweet tea. Could there have been any undesirable bacteria or mold growth that I didn't see? Is this batch still safe to drink or use as starter liquid, even though the new SCOBY seems to be doing its thing?

My main concerns are:

  • Safety: Could the initial period with the potentially dead/bad SCOBY have contaminated the batch in a way that's now masked by the new fermentation?
  • Taste: Even if safe, will the flavor be off due to the prolonged sweet period?
  • Starter Liquid: If the new fermentation progresses, would you trust this batch to be used as starter liquid for future brews?

Has anyone else experienced a dark, sunken SCOBY from an online purchase? What did you do? Any advice on whether I should proceed with this batch or just cut my losses and start fresh with a known good starter?

Thanks so much for your help! I'm a bit nervous about this one.


r/Kombucha 8h ago

Scoby check

0 Upvotes

Hey! I used to brew kombucha (with success) some years ago. It did however go bad after fermenting with fruit juice...

I recently got a new scoby and tried brewing again. It's been fermenting for 8 days now and a thin film has built up starting a new scoby layer, but I'm a bit sceptical about some dark dots that started showing a few days ago.

It smells fine, but would like some opinions.

16g black tea 240g sugar 1760g water Scoby and ~150 ml backslop

Booch from above and scoby.


r/Kombucha 9h ago

what's wrong!? Is this mold?

Thumbnail
gallery
0 Upvotes

If it is, should I just start from scratch?


r/Kombucha 23h ago

Kombucha went wrong?

Enable HLS to view with audio, or disable this notification

8 Upvotes

Hiiii I think my kombucha is getting bad or my Scoby is contaminated! What do you think? Is this normal? Is my second time doing kombucha 🫣 it has brown weird things


r/Kombucha 1d ago

what's wrong!? Blue means mold right?

Post image
11 Upvotes

r/Kombucha 13h ago

fizz Boiling Loose Leaf Tea

1 Upvotes

Instead of steeping tea in boiled water, i decided to do something different.

I added loose leaf tea to cold water, then brought it to a boil. Turned off the stove and let it sit 15 minutes. Added the sugar and then strained out the tea.

The result was dark and very cloudy. Almost muddy looking.

When I finished F1, the tea was super fizzy and turned out to be some of my best kombucha yet. I was worried it would be bitter, but it wasn't.

Have you tried brewing this way? Any reason why it would be a problem?


r/Kombucha 18h ago

What is that?

Post image
1 Upvotes

Hi, kind of new to the hobby. I tried to search for similar images but founs nothing. What is that? Is that a new scoby? Or mold(like the white one on the left border)?


r/Kombucha 1d ago

beautiful booch Here we go (starting over)

Post image
3 Upvotes

I posted yesterday about getting courage to start my kombucha over after my depression killed it a couple years ago. Today, I finally did it. My first gallon in forever. Thank you for the suggestions yesterday to get a commercial kombucha to use as my starter. I feel much more confident about this.

I am going to make a simple ginger kombucha from this batch- just to get back into the swing of things. Keeping it simple.


r/Kombucha 19h ago

what's wrong!? Mold or not roulette of Kumquat.

Thumbnail
gallery
0 Upvotes

Hey y'all, this is my first batch EVER and it's been 7 weeks since I've put it to fermentate. Named this one "kumquat". Anyway I've been wondering if this gone bad or just not conventionally attractive.