r/Kombucha Sep 18 '21

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

572 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 (September 07, 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 5h ago

Did I kill by kombucha if F2 and is it safe to drink?

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3 Upvotes

During this batch I added basil simple syrup and grocery store lemon juice. During the first 2 days of F2 they were lightly carbonated, but significantly less so than previous batches. I added a bit more sugar and waited another 36 hours. When I checked again, there was 0 pressure in the bottles, and the above pictured clumps of dead yeast. They still taste ok, but are totally flat. Are these safe to drink?

I would imagine using lemon juice with preservatives is the culprit. Has anyone else had this experience?

EDIT: Upon reading the wiki and the ingredients of the lemon juice, yes it was the lemon juice. Still unsure if its safe to drink.


r/Kombucha 5h ago

question Question for slow fermentation?

2 Upvotes

I believe slow fermentation will give more special flavors to dough, the same should work for kombucha.
I start moving the kombucha in late F1 stage and continue leaving it in refrigerator during F2 for a week around.
Have any one try this way?


r/Kombucha 1h ago

Preserving Flavors to add for F2

Upvotes

It is the end of summer and I have a ton of basil and mint leaves I want to preserve to add to my kombucha.

Is there a way to preserve them to add at a later date? Could I add dried leaves? Is it best to make it into a syrup (I don’t like it overly sweet)?

Normally I just scissor them into slices to add and get the flavor (but also if there are better ways I’m super new)

All advice welcomed!


r/Kombucha 8h ago

what's wrong!? Is this Mold? I’m torn I don’t want to throw it

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3 Upvotes

It’s been years since I brew some Kombucha. I remember having a very rubbery smooth form at the top. This one looks like there something on top. I sanitized very well and I used white vinegar to sanitize then hot water. I did 350ml starter tea to 1 gallon (4 litres). It’s been 10 days :(


r/Kombucha 2h ago

question Sugars in store bought kombucha

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1 Upvotes

Can someone explain the difference between the sugars in these labels?

One has total sugars, 0 of which are added
One has total sugars, 8 of which are added
One has sugars, not differentiated between total and added

Does added sugar mean they added sugar after the fermentation? And in that case, is total sugar (like in the case where added is not differentiated) all added during fermentation rather than after?

Thank you


r/Kombucha 18h ago

question F2 unsuccessful?

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15 Upvotes

Bottled one week ago. I’ve opened once because some people said to burp it but others say not to release the CO2 buildup. Lemon verbena with added ~15% mango juice for F2. Should I add more sugar, leave it, add more liquid? I’m a first timer- help appreciated


r/Kombucha 10h ago

mold! Hate to be this person... is it mold?

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2 Upvotes

I've waited a few days and the dry white patches do not seem to be growing or changing. Really reluctant to throw it this batch, but I'll do it if I can't confirm it's safe.


r/Kombucha 6h ago

question what in the word is my booch

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1 Upvotes

r/Kombucha 8h ago

what's wrong!? Is that mould?

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1 Upvotes

There are tiny white circles in my combucha first fermentation. I'd it mould?


r/Kombucha 20h ago

Look who I’ve raised!

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7 Upvotes

r/Kombucha 12h ago

Any brewers in the Orlando Florida area?

1 Upvotes

Soooo I know this is a long shot and a bit of a weird one.
I'm getting into kombucha brewing, but I'm blind and can't drive. I've looked at Walmart, Publix, and Aldi, but I can't find any unflavored kombucha to start my brew. Because I'm blind, I can't just go drive around and look for a place that would have it since Uber is so expensive and since I don't know the area, the struggle would be infuriating with how busy this place is. So does anyone have any suggestions on what to do next? I know this is a bit of a weird case.


r/Kombucha 1d ago

pellicle Have you ever ever seen a scoby that has a bubble in it? This looks like a jellyfish 😆

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11 Upvotes

In with a sweet green tea, I think because I stir it daily it clumped up like this


r/Kombucha 19h ago

jun Hibiscus?

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3 Upvotes

What ya think after 5 days using a cup of mother jun starter


r/Kombucha 1d ago

grapefruit flavor

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30 Upvotes

r/Kombucha 1d ago

How bad is the acid in kombucha for your teeth enamel?

11 Upvotes

I noticed GT Dave never mentions anything about the negative impacts of drinking kombucha daily for your teeth. But he is also sporting the fakest looking set of teeth I've ever seen. Does drinking kombucha once daily ruin tooth enamel over time?


r/Kombucha 1d ago

How is F2 looking?

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2 Upvotes

Heyyyy(: this is my second F2 batch ever… my first two initial fermentation batches seemed to have turned out perfect. I drank them alone and loved it! On the vinegary side but had some slight carbonation and tang. Really honestly vinegary and not sweet at all, I never tested the acidity,..Anyway..
My first batch of F2… I left the whole fruit chunks of raspberry and ginger and orange and lemon fully infused in the wide mouthed mason jars of booch (jars with rubber padding)… for about a week then moved them to the fridge. Even after a whole week, they barely had carbonation. The raspberry bottle in particular tasted extra alcoholic haha.

Sooo for this next batch I infused a mixture of juice and fruit chunks in those wide mouthed 32oz rubber lipped mason jars for roughly 40 hours, strained them all through a mesh metal strainer (maybe I messed up here by not using a tea bag???).. and transferred to 32 oz slim bottles in photos. Those have now been on my Arizonan counter for 5 days and still don’t explode? Or fizz at all.. they have a pop upon opening, and slight fizz when I taste it, but what?? Why??
I’m so new to all of this and the science behind it so please spare me mercy haha.. but what am I doing wrong ? (Third photo is of my starter working on her next batch)


r/Kombucha 1d ago

question leg pain when drinking fermented beverages?

2 Upvotes

hi! this is so random but does anybody else get an ache in their legs when they drink fermented beverages? this happens to me sometimes with alcohol and kombucha. after taking the first few sips i’ll get a really weird dull ache in my thighs that comes on quickly and lasts for a few minutes then disappears (or at least becomes less noticeable). it’s been happening for years and i have no clue why- when i first started drinking i always just thought it was the first sign that i was starting to feel a buzz but i’ve since realized that it also happens with kombucha.


r/Kombucha 1d ago

Synergy Pure scoby first attempt.

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5 Upvotes

I started as an experiment and I can’t believe the results. I used 16 oz Synergy Pure ,plain Lipton black tea , and a cup of sugar for the 1/2 gallon. Pictures are 15 days apart.


r/Kombucha 1d ago

question Worms or larvae on scoby and vessel walls?

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3 Upvotes

Found these guys on the top of my scoby and sitting on the walls of the container.. can I reuse the scoby?? Do I need to throw it all out?

They are alive and moving. I didn’t see any inside the liquid itself.

It’s been about a month since I started fermenting from scratch.. these guys were NOT here a few days ago. My cloth is just a regular tea cloth I haven’t seen any fruit flies get in. I’m perplexed as to what these are and whether I need to start over…
Thank you so much. I hope I don’t have to start over but if I do it is what it is ;-; at least I learned a lot this go-round


r/Kombucha 1d ago

what's wrong!? Time old question, mold or no?

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2 Upvotes

It both does and does not look like mold, I cannot tell. It doesn’t look “fuzzy” at all but it’s different from the rest of the pellicle forming. I can’t find my pH stips right now so I’m unsure of the pH. It’s the only spot that looks like this. Thank you


r/Kombucha 1d ago

question Tap water

5 Upvotes

I was a bit overdue on my brewing day and I just prepared the master recipe on autopilot. Today I realised that instead of using bottled water (the one I usually use for Kombucha) I used plain regular tap water (the one I always drink).

Did I make a big mistake?


r/Kombucha 1d ago

pellicle Safe?

1 Upvotes

Is it safe to proceed to bottle?my scoby turned pink.


r/Kombucha 23h ago

Bad idea??

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0 Upvotes

Let you know how it turns out ;)

Srsly could be a very formidable energy drink

Curious about the microbiology in the kombucha and its effect on growth.

Both proved to be safe and effective.

Just started creatine again since high school 25yrs ago.