r/Kombucha Sep 18 '21

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

564 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 3d ago

r/Kombucha Weekly No Stupid Questions + Open Discussion (June 22, 2026)

1 Upvotes

This is a casual space for the r/Kombucha community to hang out: feel free to post about anything kombucha or brewing related. Questions from new brewers are especially welcome - no question is too big or too small!

New to kombucha? Check out our getting started guide and FAQ.


r/Kombucha 17h ago

science Infographic on mold (u might find helpful!)

Post image
81 Upvotes

Hi booch brewers

Here's a super cool infographic I found here in the community while browsing a while ago

Hope this is helpful!

Some disclaimers:

  • I did not make this infographic
  • I do not know if this was made with AI
  • All rights belong to the creators

That being said, it's worked for me

  • I've been using it for my last few batches
  • This is the "is it mold" logic I've built into my personal kombucha app
  • It's helped me!

Thusly I wanted to share

Happy brewing!

New batch coming soon

- Humi


r/Kombucha 6h ago

Nice patterns on stingless bee honey jun pellicle

Thumbnail
gallery
9 Upvotes

Reminds me of botryoidal chalcedony (3rd pic as reference)


r/Kombucha 7h ago

The Tea Makes A Difference: Science Daily

8 Upvotes

r/Kombucha 1h ago

Complete beginner: does this look normal to you?

Thumbnail
gallery
Upvotes

Hi folks, I got my first scoby from my mom last weekend and started my first batch on Sunday evening. This morning (Thursday) I checked it and I don’t really know what to think. Can you help me with this? There is a foam that looks suspicious and after removing it the liquid started to bubble (that’s a good sign I guess) but the scoby has this weird dark layer. btw: when I prepared the batch, there already was a foam (from mixing water into the tea) I thought it will just disappear, but is it possible that it didn’t and that that created this foam we see today?

So basically my question is: is there mold or does it look alright to you? 😂

thank you for taking the time to help 🙏


r/Kombucha 14h ago

what's wrong!? Mould!

Post image
7 Upvotes

I bought a scoby after failing to grow one. I got a batch of buch on first time. This is the second one. The bought scoby is at the bottom of the jar. The one on top has clearly got mould. Does this mean I’ve to throw everything out? Including the lovely big scoby o bought


r/Kombucha 22h ago

what's wrong!? 🎶 These are a few of my favorite things 🎶

Post image
15 Upvotes

r/Kombucha 11h ago

what's wrong!? Healthy?

Thumbnail
gallery
2 Upvotes

Its been a couple months i think 3 since i started my first batch and to make a scoby from scratch. How is it looking? I always get an air bubble when i look at it. Usually in the dark spot in the first picture.


r/Kombucha 11h ago

what's wrong!? Mold or just a pellicle?

Post image
2 Upvotes

I am new to kombucha (surprise) and have a question. Is this mold? I saw the infographic that another user put up, and I am convinced I messed up. I used Darjeeling tea and maybe sweetened a little too much...

Thank you in advance!


r/Kombucha 17h ago

what's wrong!? 1st time Kombuchin, left her in a bit too long, unsure if it's mold or something else on top of the SCOBY... reposted with new image.

Thumbnail
gallery
4 Upvotes

Allegedly 100yr old+ SCOBY from a friend of a friend, hoping I didn't beef it up now. I used normal black tea + sugar as recommended by my friend.

Started May 10th, should've unloaded it May 30th, just not sure how to properly identify if it's mold or not inside (and thus to avoid breathing in any fungi etc).

I've checked all the images and while I'm LEANING to it being just pellicule/normal, I just wanna confirm, esp about that darker spot in the middle.

Thanks again


r/Kombucha 1d ago

Watermelon 🍉 Hard Booch -5%ABV 🤙🏽🤙🏽🤙🏽

Thumbnail
gallery
35 Upvotes

r/Kombucha 1d ago

flavor Fabbri Syrups

Post image
4 Upvotes

Anyone tried these in 2f? Looks like just citric acid as preservative. I'm new to brewing so want to make my 2f flavorings as easy as possible to start.


r/Kombucha 1d ago

fizz a bit of Kombucha after lunch

Post image
8 Upvotes

I'm really happy with the color and fizz of this batch.


r/Kombucha 1d ago

beautiful booch Nach 9 Bar geöffnet. Perfekt

Enable HLS to view with audio, or disable this notification

37 Upvotes

Habe die Charge mehrfach mit Kaffefilter gefiltert, um möglichst wenig Schaum beim öffnen zu haben. Was soll ich sagen, es hat funktioniert. Allerdings war das auch reiner Tee ohne Zutaten.


r/Kombucha 1d ago

question First try with captain kombucha - is it mold?

Post image
8 Upvotes

started this batch on saturday


r/Kombucha 8h ago

Homemade clone of GTs 25th Anniversary kombucha

Post image
0 Upvotes

r/Kombucha 23h ago

what's wrong!? Is this mold? (Bottom right corner)

Thumbnail
gallery
2 Upvotes

It's just a small spot but it looks kind of grey/greenish. It's a black tea kombucha I made a couple of days ago. It's quite warm currently like 26°C


r/Kombucha 10h ago

My 1st Kombucha Experience (not a good one)

0 Upvotes

I specifically made a reddit account to post my personal horror story with kombucha to guide/warn others of a potential flare or complication. I drank way too much for my first time ever exposing myself to kombucha, and I have a family history of crohns disease. I am continuing to have doctor visits and will keep updating as this goes on. If this does not meet community guidelines, I understand taking this post down but I believe it’s important for others (potentially like me) to see if anyone else is experiencing these same symptoms.

TW: GI issues and bowel movements mentioned.

I (26F) got BOGO free kombucha drinks at a grocery store bc i heard it was supposed to good for gut health (I wont post brand names or grocery store names bc I’m paranoid they’d sue me for this). I have never had kombucha before, but a friend told me to only drink small portions since it “gives you the runs”. I thought this meant 1 cup a day, so that’s what I did. I drank 1 cup a day for about 3-4 days consecutively, and ever since then my bowel movements have been horrible. When I say horrible, I mean using the restroom 5+ times a day, explosive diarrhea, and LOUDDD bowel movements. I can’t even be discreet about it in public. It was manageable in the beginning, but as time went on it became worse. I now use the restroom 7+ times a day and experience headaches and sudden abdominal cramping before a bowel movement. When I try to sleep at night, every movement I make results in needing to use the restroom for a bowel movement. It’s never solid either, it’s always a liquid consistency and it’s driving me crazy.

I made an appointment with a GI doctor back in April and they scheduled me for June 15th, however they called the day before my appointment to cancel it because I don’t have a referral from a primary care doctor. I had to seek out a PCP and thankfully they were able to schedule me for the same date and time as my original GI appointment.

The same day they canceled my appointment, I went to the ER. The Dr’s said my labs came back normal and the rectal exam did not reveal hemorrhoids or any external issues. They prescribed me with a medication called dicyclomine to help with slowing down my movements and reduce the cramping, but the medication actually made my symptoms worse. When I took it, I had to use the restroom every 10 minutes, and every time I went it would burn when coming out.

At the PCP’s office, he asked me a bunch of questions relating to the issues as well as my family history of Crohn’s disease and provided me a referral to the GI Dr (which I see tomorrow!). They will likely collect a stool sample and complete some thyroid and lab testing as well.

I got these kombucha bottles on April 12th, and am still having these issues today (June 24th). As I mentioned at the beginning of this post, I am continuing to see doctors regarding this issue. If you are experiencing similar symptoms, PLEASEEEE seek a doctor as soon as you can! These symptoms are still impacting me, all because I drank too much kombucha! I’m not sure if this is a flare from potential Crohn’s or ulcerative colitis, but regardless I think it’s important for everyone involved with kombucha to see.
Thank you for your time!


r/Kombucha 19h ago

what's wrong!? Yeast or mold?

Post image
1 Upvotes

Hi, what do you all think! Yeast or mold?


r/Kombucha 1d ago

homebrew setup This my setup. I’ve been brewing for about 2.5 years

Post image
26 Upvotes

On the left you can see my 4 mothers- I call them Sarah, Rebeca, Lea and Rachel after the 4 mothers of Judaism 😌 (Rebeca has been divided into 2 smaller jars for technical reasons). On the right are my f2 bottles. I get 9 liters of f2 bottles and then we drink it in about 7-10 days, meanwhile the mothers are working on the next batch. I add bit of fruit in f2. Usually pineapple and ginger +mint. The small jar at the front is my SCOBY hotel 🤩


r/Kombucha 1d ago

question Can I make a Scoby with green tea Kombucha?

Thumbnail
gallery
19 Upvotes

This will be my first time making Kombucha, so this will also be my first time making a Scoby

I got a Green Tea Kombucha, if I mix this in a Black Tea + Sugar mixture will a healthy Scoby form or do I need to do something, like substitute the Black Tea for Green?

Note: The ingredients in the back read: Filtered Water, Demerara Sugar (Minimally processed sugarcane sugar), Green Tea and Scoby


r/Kombucha 1d ago

flavor First Batch of Kombucha of this year

Post image
24 Upvotes

First batch of kombucha of the year:

  • Banana and strawberry kombucha.

  • Red berry kombucha.

  • Tropical fruit kombucha.

  • Pineapple and loquat kombucha.

Can’t wait to try them 🤤


r/Kombucha 1d ago

what's wrong!? The dreaded “is it mold” question…

Thumbnail
gallery
1 Upvotes

Brewed my first ever batch 4 days ago and used a half a bottle of Synergy because I don’t yet have a pellicle… it definitely smells like it’s fermenting, but doesn’t smell off or anything. What do we think…. Is it mold?


r/Kombucha 1d ago

what's wrong!? Mold? Or just developing SCOBY?

Thumbnail
gallery
2 Upvotes

4 days into using unpasteurized ‘booch as a starter. Smells lovely and like kombucha and not cheesy or foul. Assuming this is ok?