What’s That White Waxy Layer Growing On My Kombucha Brew?
If it’s not fuzzy, your kombucha batch is probably healthy. Let’s find out.
Let’s talk pellicles.
A pellicle refers to the membrane or skin. During kombucha fermentation, a pellicle will form on the surface or air-liquid barrier. This little (or sometimes very big if left alone) membrane has become the face of kombucha, sometimes referred to as the mother, mushroom, baby, or simply SCOBY.
SCOBY stands for Symbiotic Culture Of Bacteria and Yeast and refers to the microbes in kombucha.
Culturally, though, it has become common for “SCOBY” to refer simply to the pellicle.
The pellicle is made up of bacterial cellulose. Fun fact: cellulose, typically associated with the cell walls of plants, is also produced by bacteria! Bacteria are so cool!
The synthesis of bacterial cellulose is a side effect of the fermentation processes, not the ultimate goal of tasty kombucha.
If no cellulose is produced, aka no pellicle forms, does this mean that the bacteria are dead or not fermenting? No. It just means they aren’t producing cellulose but are doing other microbial things, which is totally okay. This is good news if you are worried that your culture is not “making a baby.”
If your kombucha isn’t reproducing a pellicle, yet all other signs are pointing to fermentation (lowered pH, lightening of color, vinegary scent, signs of bubbles, no signs of mold, and tastes good) then continue on brewing. Over consecutive brews, you will most likely get pellicle production if it’s not happening right away. Even though it’s comforting to see a pellicle growing as a sign of a healthy fermentation, it isn’t all or nothing.
If you are trying to increase the production of cellulose, try aerating your brew early on by stirring vigorously. This extra oxygen can help boost pellicle production.
What should the pellicle look like? There’s no one answer. Kombucha pellicles can grow in all sorts of weird textures, and grow to the size of the container that they’re brewed in. The structure is comprised of cellulose sheets that bond together vertically, which results in a thickening appearance over time. At the beginning of the brew, it will be just super-thin microfilm. This is when most newbies start to get concerned if they’re doing things right or not. The film is translucent at this time, showing yeast globs forming underneath–alien looking stuff to an untrained eye. Once the film begins to thicken, it looks more familiar, gains a waxy, white or tan appearance, and sighs of relief start to reassure the new brewer that all is right in their microbial world.
There’s no one perfect way for a pellicle to look, so don’t worry if yours looks off-putting. Just love it anyway and tell it that it’s special.
Here are some examples of healthy new growth:
And here’s some healthy established growth:
Notice that on the first photo, the pellicle has sunk to the bottom–all good because a new one will form on the top, just like in the second photo where you can see the layering. In the third photo, you can see that the pellicle is raised off of the liquid almost an inch at parts–this happens when carbonation builds up and pushes the pellicle up to escape–you can either push it down or just let it be.
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informative and fascinating as always! thanks so much! it’s like you read my mind before creating these articles.
Thanks Keith! Great minds think alike!
Oh thank you! I know it continues to grow but wasn’t sure what it was.
Over several brews my jars accumulate a lot of STUFF floating around on the bottom. At some point should i filter that our of the jar, or just leave it? I
Love the info, keep out coming.
Hi Renee! That stuff floating around is just yeast and will build up over time. You can filter it out every now and then, maybe every few brews or so. Filtering it can help maintain the balance of your yeast and bacteria populations. It’s perfectly healthy to drink the sediment though so no worries if some of it get into your bottles. Thanks for reading :)
I was gifted a SCOBY for my first brew. While that SCOBY sank, a solid layer formed on top; I was told that was a pellicle. So, they are the same thing?? So, now I’m on my third batch using both the SCOBY and what I thought was a pellicle. The “pellicle” is getting very thick, but the initial SCOBY isn’t changing at all. What do I do with both of these things now? TIA!
Hello! The original pellicle will never change in size unless it happens to float because the growth occurs at the surface. The original will typically sink because of the weight of the liquid on top. I like to separate the term pellicle from the SCOBY because the SCOBY refers to the living organisms where as the pellicle is just a cellulose byproduct of the fermentation, so that’s where the confusion might arise. You can discard the original & thin out the pellicle as you wish because a new one will grow with each batch.
Thank you so much for the clarification!
Hi, thanks for the explanation. I have just brewed tea, let it ferment for 10 days, and now flavored it, fermenting it for anther 7 days. Can the Pellicle that formed be used exactly as my skoby? in other words, can I use it in place of the skoby I used to make the tea in which the pellicle formed?
Hi Mary,
Yes, you can use it just like you would the original, but be sure to use enough starter tea with it as well (1.5-2 cups per gallon).
Best,
Ruthie
Still a little confused… my SCOBY sank to the bottom and I have a thin layer of pellicile on top. When I go to make a new batch, which do I use? I though the instructions in the kit we got said reuse the SCOBY
Hi Ryan,
You can use either one or transfer both. Just be sure to use enough starter tea and you’ll have a great brew.
Cheers,
Ruthie
Hi! Why do I need to transfer the pellicile at all, as long as I transfer a starter tea to the next batch?
Hi Jorn,
You don’t have to, but it definitely doesn’t hurt.
This was very helpful, I got a new scoby (getting back into kombucha brewing) and the scoby wasn’t floating. I got worried since in the past this has always happened. However today I did see a thin pellicle at the top and the scent is getting more vinegary. I think I need to wait and see what happens, but I feeling like things are going well!
Thank you so much for the information. I am making Chaga Kombucha and was very sad that no pellicle was forming. I thought I was going to have to toss it. You’ve set my mind at ease. Thank you so much.