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 1d ago

r/Kombucha Weekly No Stupid Questions + Open Discussion (August 31, 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 2h ago

not fizzy Can’t get carbonation

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6 Upvotes

Hello all - I’m on f1 of batch three of my kombucha (just finished drinking the last bottle of 2nd batch f2) and cant seem to get my booch to carbonate. I’ve tried filling each bottle with a variety of different things - honey, ginger, mint, simple syrup, lemon juice, orange juice, blueberries, raspberries, straight up sugar etc. and some bottles with only one or two others with a combination of several of the above and none of my bottles has become carbonated. I’ve tried leaving them out for longer as well. Is there something wrong with my f1 or? Photos of third batches f1 attached.


r/Kombucha 11h ago

homebrew setup Best upgrade on kombucha

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15 Upvotes

Back in college I’ll used to make this stuff without the spigot. I would just scoop it out with a ladle and pour it in bottles using a funnel. I had lots of time back than. Things are different now I gotta thing faster pace

Another upgrade I wanna get because winter is coming is I dual heat mat and another 2 gallon jug to make another batch cuz a friend offered me some of his vegetables for a couple gallons of kombucha.

I definitely need to insulate the house better not just for the brew but for me as well. When the woodstove goes out it gets down below 62 sometimes even with the heat on. That’s what happens in below 0 degree weather in upstate NY In a poorly insulated house lol

If there’s any other upgrades you guys can tell me about lmk I’d love to hear


r/Kombucha 1h ago

Seeking Copycat Recipe

Upvotes

I’m looking for a copy cat recipe of Synergy Guava Goddess. I’m new to kombucha making. I tried making a copy cat myself but it was too sweet and could have been carbonated more.

If you have a complete recipe to include second ferment time for a good carbonation.

I have a one gallon brew jug. Any help appreciated.


r/Kombucha 22h ago

beautiful booch Look at these beauties 😍

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68 Upvotes

I just refreshed my jars and felt like sharing.

Left: Oolong

Middle: Hibiscus

Right: Red raspberry leaf + green tea


r/Kombucha 6h ago

Total Newbie - First Brew , F1 complete, started F2

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3 Upvotes

Using Pineapple Ginger & Pomegranate mint for F2 . Please suggest ways to improve 🙏


r/Kombucha 57m ago

Carbonation

Upvotes

Having carbo problems any help would be appreciated. I've only made 4 batches been at this about 6 weeks or so now!


r/Kombucha 15h ago

question New to kombucha, please explain this to me like I’m 5

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14 Upvotes

I got this scoby from my friend recently, and it’s just been standing around. I’ve looked online for what to do with it now, but I keep meeting words and terms I don’t understand (like f1 and stuff), and I’m just overwhelmed , especially since half the recipes are with ounces instead of liters😭would anyone be willing to explain to me what to do from here, like I’m incredibly dumb and 5 years old, because I think I need that. The pictures are of my scoby, I hope it’s healthy.


r/Kombucha 7h ago

Ever seen this?

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3 Upvotes

I have added sugar and a store bought juice before F2.

The juice was 100% natural and my guess is that something inside reacted with the kombucha.

Gas then brought towards the exit this weird looking scoby.

What's your guess?


r/Kombucha 2h ago

Day 11, Safe Still?

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1 Upvotes

Tasted at day 7, scoby sank, tea still tasted really sweet. Starting ph was 3.5. For some reason it’s taking a long time to ferment despite being held at 78-80° for 11 days.


r/Kombucha 5h ago

what's wrong!? Very first time

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1 Upvotes

I bought a scoby online and put in.

It's been about 4-5 days. It smells very acidic like vinegar. My scooby likes to.stay just below the surface underwater. But there's this white film forming. Nothing looks fuzzy. Does this look healthy?


r/Kombucha 5h ago

what's wrong!? What is the problem with my batches

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1 Upvotes

Hello!

I am new to kombucha world. I made some bathes with my starter liquid, and I managed to make some really nice Scobys.

My problem is that my F2-s have very acidic taste, and has really low carbonation. And I don’t know what do I do wrong.

Here is what have I done:

F1:
3 liters of black tea (from approximately 15g-s of tea)
180 gramms of cane sugar
300 ml of my starter liquid
Scobys

4-5 days at 26C

F2:

50 ml of elderflower syrup
Rest is F1 for 1 liters

Please help! Picture of my F1 (it’s not the full F1, I have already used some for some experiments)


r/Kombucha 6h ago

question Is my SCOBY forming properly?

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1 Upvotes

I recently bought a starter kit online. It came with a small amount of starter tea, a SCOBY, tea, and sugar. I followed the instructions in the manual. For the first three days, everything seemed normal, but I ended up pushing the SCOBY that had formed down into the tea, and now it looks like this. I'm a beginner at this, so is my SCOBY forming properly? I couldn't find anything about this kind of "bubbles" forming on it.


r/Kombucha 6h ago

question Kombucha-SCOBY als Reserve im Kühlschrank aufbewahren – wie macht ihr das?

1 Upvotes

Mein SCOBY ist nach mittlerweile 3–4 Ansätzen ziemlich stark gewachsen. Ich würde deshalb gerne einen Teil davon als Reserve aufbewahren, falls mir der aktuelle Ansatz irgendwann durch Schimmel, Fruchtfliegen o. Ä. kaputtgeht.
Mein Plan wäre, ungefähr die Hälfte des SCOBYs mit ca. 200 ml Ansatzflüssigkeit in ein sauberes Glas zu geben und im Kühlschrank aufzubewahren. Mit der anderen Hälfte würde ich direkt den nächsten Kombucha ansetzen.
Funktioniert das so oder sollte ich dabei etwas beachten? Muss der SCOBY im Kühlschrank komplett mit Ansatzflüssigkeit bedeckt sein? Sind 200 ml ausreichend?
Und wie lange kann man ihn auf diese Weise lagern? Muss man ihn zwischendurch mit neuem gesüßtem Tee versorgen oder kann er einfach im Kühlschrank bleiben, bis man ihn wieder braucht?
Wäre es außerdem sinnvoller, nur die Hälfte des SCOBYs als Reserve aufzubewahren und den Rest weiterzuverwenden, oder gibt es eine bessere Methode, eine Reserve zu halten?


r/Kombucha 10h ago

Checked the jars and tasted them

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2 Upvotes

The second jar was slightly over-fermented, but still drinkable, and formed its own thin SCOBY (pellicle). I poured off liquid for drinking purposes and added fresh tea.

The third jar got definitely way too sour, it tasted more like vinegar than kombucha. I used it as a starter for a big 3-liter jar to grow a large SCOBY (pellicle). Before this, at most I used 1-liter jars.

The first jar is still going well. I don't remember how many batches I've already made. I just change the tea periodically and drink the resulting liquid. The only issue is that the taste sometimes becomes a bit bitter, regardless of which type of tea I use: green tea bags, black tea bags, or loose-leaf black tea.

Previous post for context: https://www.reddit.com/r/Kombucha/s/sA8xLxyo2i


r/Kombucha 7h ago

At which ph is kombucha/jun done?

1 Upvotes

I‘m training a kombucha scoby to be more for Jun, so been using green tea and honey instead of black tea and sugar. This is my second batch with this scoby. I started F1 a week ago, used a tiny amount of pellicle that I had, and strong starter tea. The ph is only between 3-4 after a week but the pellicle has grown and looks great. I did taste it, and it’s definitely acidic. I struggle with F1 tasting and knowing when it’s ready for F2, so trying to use ph as a more concrete answer. Which ph do I need for a kombucha/jun F1 to be ready for F2? and how long should this process be?


r/Kombucha 1d ago

fizz Too much head.

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20 Upvotes

Hi,

So I force carbonate in the fridge after a short 24 hr F2. Initially I set my half-gallon keg at 25 psi and bleed/drop regulator down to 5 psi after 24 hrs.

Problem is it’s too GD foamy every pour. Happens every batch (this one happens to be grapefruit strawberry).

Ideas?


r/Kombucha 11h ago

jun Jun Kombucha

1 Upvotes

How do I make Jun? Since it's made with honey instead of sugar. Can I make it with Kombucha Scoby(starter liquid and pellicle)?


r/Kombucha 1d ago

question What's the deal?

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25 Upvotes

Very similar expiry, two different shades. Just wondering what in the process might cause this.


r/Kombucha 16h ago

pellicle What is this?

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1 Upvotes

I don't think it's mold based on the pictures on this reddit. I'm still curious about what exactly those circular patches of film are. Is it just the pellicle multiplying?

The Scoby has been fermenting for 5 days.


r/Kombucha 1d ago

question Berätta om din kombucha-rutin

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4 Upvotes

Jag har precis börjat göra egen kombucha och älskar det! Men - jag känner att jag har svårt att hitta en bra rutin för mina bryggningar. Ska jag slänga scoby efter varje jäsning, eller spara den? Hur länge ska den jäsa i de olika faserna? Vilka verktyg är bra att använda och hur gör jag för att hålla allt vid liv?

Skulle vara så kul att få höra om era rutiner och hur ni gör för att lyckas med er kombucha!


r/Kombucha 23h ago

question Trying to grow a scoby, it breaks and sinks.

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2 Upvotes

The kombucha tastes fine. Nice and tart. I used raw unflavoured kombucha with sweet tea. This is 3 weeks in. The top layer is very broken apart and thin with a lot of sediment on bottom. Is this ok ?


r/Kombucha 1d ago

Does my kombucha look ok?

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3 Upvotes

Hello, I’m a first time brewer and would like someone to check my kombucha:) it’s the fifth day of brewing, I’m using black tea with sugar. I’m unsure about the little dark stuff floating/settling around the surface/Scoby. Any advice would be appreciated. Thanks!


r/Kombucha 1d ago

what's wrong!? Is this mold?

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1 Upvotes

Hey, I'm anxious about my first batch, I'm still learning

The grey-blue color concerns me, it is not dry. Is this fine? Thanks for helping ♥️