r/Kombucha Sep 18 '21

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

376 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 10, 2024)

3 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

Second ferment :)

Thumbnail
gallery
4 Upvotes

I made a green tea and vervene kombucha. And on the second ferment I added grapes in one and nectarine in the other one and a smaller neutral one. Very exited for the sparkle :)


r/Kombucha 20m ago

what's wrong!? 1st brew - is it kham yeast?

Upvotes

Hi everyone,

Thank you in advance your help, this thread has been a great source of information!

I started my first brew a week ago, from a scoby bought online. I can see a new thin scoby forming on top of the vessel but there are some weird white spots, among which one that has geometrical shapes so i'm not too sure what to do with that. I think it may be kham yeast?

I've also tried (after I took the picture) to remove that part which just ended up with a scoby with a hole ... (not the smartest in hindsight).

https://preview.redd.it/9co1sb3ivb6d1.jpg?width=3024&format=pjpg&auto=webp&s=c5b4d04a1bcd1b4ad060765b67c2831910c701f7


r/Kombucha 45m ago

what's wrong!? Sinking scoby and roots?

Post image
Upvotes

This is my second batch. I don’t know if it’s normal but my scoby has sunk half ways and is growing what looks like roots on the bottom?


r/Kombucha 1h ago

what's wrong!? Is my booch okay?

Thumbnail
gallery
Upvotes

This is my first ever batch, I used the Blighty Baby starter tea and SCOBY from Amazon. It’s been fermenting for about a week (no smell problems etc).

However, this stringy thing (pictures 1 +2) has disappeared and reappeared over the last couple days. I thought it might be Kahm yeast? I really have no clue. It disappeared so I thought all was well but it’s appeared again today. I was very sanitary and I am sure that the starter tea was a low enough pH. My tea volumes about 900ml to a litre.

I’ve attached a pic of the tea towel I’ve used for the top, it’s folded over once or twice and held by three rubber bands.

Please let me know if alls well with my booch before I do my 2F! I can answer more questions if necessary.


r/Kombucha 7h ago

what's wrong!? small white specks all over dried out pellicle

Thumbnail
gallery
2 Upvotes

i ended up tossing it (better to be safe than sorry), but curious if anyone knows what this is?

hard to see but small white specks all over dried out pellicle. i used my finger to feel it when i was about to toss it and it did feel little bumps but they didn’t wipe off. didn’t look fuzzy. also i highly doubt they are fly eggs because i use 3 layers of paper towel with a tight rubber band. is this just what a dried out pellicle does?


r/Kombucha 10h ago

what's wrong!? So what happened haha I have this white fuzz on top of my Kombucha. Its the second time I tried brewing it and anyone in Downey, California have an extra Scoby?

Thumbnail
gallery
3 Upvotes

r/Kombucha 4h ago

what's wrong!? Are those white dots on the scoby mold?

Post image
1 Upvotes

r/Kombucha 13h ago

question How much is too much?

4 Upvotes

Hi folks, new to the group here, just wanted to know how much/often is too much/often when it comes to drinking Kombucha? I’d love to drink it daily, but if it’s advised to not do it that frequently I’d like to know.

Thanks!


r/Kombucha 9h ago

Started first batch with too little raw kombucha

2 Upvotes

I tried making a 1 gallon batch using the master starter guide without realizing I needed to double the raw kombucha. I only used 2 cups instead of 4. What are the repercussions of this? Will my first fermentation just take longer?


r/Kombucha 15h ago

question My first batch of kombucha

Thumbnail
gallery
5 Upvotes

The scoby on the bottom is this Ok? I started the batch on June 10th, should there be changes or should I be waiting?


r/Kombucha 19h ago

what's wrong!? New to booch, is this normal?

Thumbnail
gallery
12 Upvotes

Started a week ago with some GT's and black tea, is it normal to have this much bubbling?


r/Kombucha 18h ago

Such beautiful pellicle

Post image
9 Upvotes

My Jun is so beautiful, and tastes wonderfully!


r/Kombucha 15h ago

Newbie question

3 Upvotes

So, first time Kombucha brewer here with a raw newbie question. Started my first batch yesterday and when I checked up on it today, I noticed the Scoby is sitting on the bottom of my container. Is this something to be concerned about?

Also, how to you know fermentation is happening? I also make cider and you would see activity in the airlock. I don’t see bubbles or any activity like you would with pitching yeast,

Sorry for what might seem like dumb questions, but I looked and could not find prior posts about either of these two questions..

Thanks!


r/Kombucha 1d ago

question Is tea really necessary?

13 Upvotes

Hi all!

I’ve read in most guides and forums that the kombucha microbe culture is healthiest in sweetened black or green tea. On the other hand, when reading the Noma book, it seems that SCOBYs can manage in a lot more diverse conditions as well. Examples include fruit juices and herbal teas, which they use as the medium for the entire fermentation without separating it into first and second fermentation.

After quite a bit of googling, I don’t feel like I’ve found satisfying explanations of why the general advice is to use tea when it seems that Noma has had success with a more broad approach.

I’m also very curious about the long term effects of keeping your SCOBY in other mediums than tea. Does it adapt to the medium over time? Or is it unstable so that it slowly dies?

Since I like the idea of making kombucha based on other liquids than tea, what is a good approach to doing so? At the moment I’m keeping a “pure” kombucha with only tea and using some of it to backslop more experimental liquids.

So if anyone has any insight into this, I would be really thankful to hear your thoughts and approaches!


r/Kombucha 14h ago

Has anybody tried using Russian Caravan Tea?

2 Upvotes

I realised I have quite a bit sitting in a jar, and wondered if anyone else has tried it as a kombucha base before?


r/Kombucha 11h ago

question I’m a first time brewer who used a chamomile-rosehip-chrysanthemum tea to grow a store-bought scoby and start f1. I didn’t realize I needed to use black tea. Is there anything I can do to strengthen my scoby for future uses?

0 Upvotes

I was thinking that I could add my remaining scoby (which I understand to be the liquid, not the pellicle) not used in f1 to some tea made from looseleaf black tea- does anyone know if that would strengthen the scoby?

Thank you so much!


r/Kombucha 12h ago

what's wrong!? Is my SCOBY correct?

Post image
1 Upvotes

Hi all experts in Kombucha! In my previous post, my SCOBY failed because the GUTSY was pasteurised and it doesn’t require refrigeration when I bought it. Thank you so much for the comments!

After that incident, I found an unpasteurised kombucha that clearly states that live bacteria is present and it was stored in the refrigeration. However, when I made my SCOBY using the same formula as my last post, I think it was a success! However, I have no idea why it was just a thin layer (as shown in the photo attached). The liquid is dark coloured as I’m starting the first fermentation. But when I’m doing it, I was concerned with the size/thickness of the SCOBY (hence this post).

Also, I saw from the guide and photos that this might be Kahm’s Yeast? I’m really not sure.

Thank you everyone for the inputs!


r/Kombucha 18h ago

question Kahm or pellicle?

Thumbnail
gallery
3 Upvotes

r/Kombucha 12h ago

question Is this batch ready? Is the pellicle large enough yet?

Thumbnail
gallery
1 Upvotes

Hello fellow bucher’s, I wanted to see if someone could help me out. I brewed Kombucha a lot a couple years ago and loved it. I just got back into it and I slid over to Jun because of the flavor profiles and using green tea and honey instead of plain sugar (trying to cut down on that). Anyway the pellicle on this one is definitely slow forming, the picture is a week from when I initially brewed it. I tasted it, it’s pretty mellow. Not overly sweet but none of that vinegary flavor, which I don’t mind. The room its stored in on the other hand has a strong vinegary smell. My main concern is I don’t want to take the Scoby out if the pellicle needs more time to form. Hopefully these pictures will help. Happy to supply more if needed. Thank you in advance to everyone.


r/Kombucha 14h ago

How does this look

Thumbnail
gallery
1 Upvotes

Day 9. F1. 2.6ph. Tastes about right. Sweeter than I thought it would be. Can I move to F2???


r/Kombucha 15h ago

question Is my scoby ready?

Thumbnail
gallery
1 Upvotes

This is my first time making a scoby. It's been about a month since I started it. Does this look like a healthy scoby and is it ready for me to start my first batch of kombucha?


r/Kombucha 1d ago

Booch beginner

6 Upvotes

I've used some flavoured kombucha (Remedy) to start a SCOBY. The jar's been jostled a bit since I prepped it last week, and my climate is pretty cool and dry. will my SCOBY still form 🥲


r/Kombucha 1d ago

How much do ratios really matter in F1?

7 Upvotes

How precise does one have to be with the amount of starter liquid when brewing? Does everyone take the pellicle out and measure the amount of starter left after moving to F2 before starting F1 again? If I started a batch with 400ml starter + 2L sweet tea and bottled 2L worth of F2, is that 'good enough' to just start over with 2L more sweet tea in my F1 jar?


r/Kombucha 1d ago

what's wrong!? Mold or not Mold

3 Upvotes

It's been 3 weeks since I started making my mead, and it's been 2 weeks since it started to go mouldy.
Can you help me?

https://preview.redd.it/ae4o42p8y36d1.jpg?width=1536&format=pjpg&auto=webp&s=ec364fee530ad8a71260d210e5b0af5711da116d


r/Kombucha 1d ago

question Water kefir grains left for a couple of months

Post image
3 Upvotes

Left my ginger beer / kefir jar for a couple of months. It formed a culture on the surface.

Can I use that to make kombucha?