Brewing Kombucha at home is a fun and easy process. However, to the newbie, the Kombucha brewing process can be fraught with uncertainty, mostly due to lack of information. For some, the mere sight of a healthy SCOBY alone is enough to inspire shudders of revulsion to the uninitiated.
Like most hobbies: the more you brew, the greater your skill set. With experience comes familiarity, but first you must learn to “speak Kombucha.” Heck – you might end up like us, singing to your cultures and calling them your Boochie Babies!
Since a healthy SCOBY can come in a variety of shapes, sizes and colors, it can be easy to mistake a healthy brew for a science experiment gone awry.
This quick guide covers the top signs your Kombucha is healthy — plus a few “looks weird but totally fine” notes to save you from unnecessary panic (and unnecessary SCOBY funerals).
A healthy Kombucha brew usually has:
The goal isn’t a perfectly sterile jar — it’s a stable, thriving fermentation.
Kombucha has its own special smell that longtime brewers will immediately recognize. The signature sweet-sour smell of Kombucha wafting from the brewer is a unique delight. It may take a couple of days for the smell to appear but it is unmistakable once you learn it.
Sometimes described as fermented or “beerlike,” it also has notes of vinegar and a slightly sour pungency that indicates a healthy SCOBY and KT. If you store your Kombucha in a smaller room, you may notice the smell is stronger than when stored in a more open space.
TRY THIS – Smell your batch everyday and taste it too. You will quickly learn how to detect how much sugar is present with just your nose.
Quick sniff test
If it smells like:
If it smells like:
One of the most obvious signs of a healthy Kombucha brew is the formation of a new, Healthy SCOBY (Symbiotic Culture of Bacteria and Yeast – often referred to as a “baby”). While SCOBY growth will vary with the seasons due to differences in temperature, air pressure and the like, the culture is hardy and is constantly reproducing as part of its survival strategy.
SCOBYs do not miraculously appear fully formed, but grow in gradually until the entire surface area of the brewing vessel is covered. This survival strategy creates a seal which slows down evaporation and allows for the anaerobic fermentation to occur.
Since Kombucha is of nature (as we are) it follows the seasons. In the summer, the Kombucha ferments very quickly and SCOBY growth is more rapid. In the winter when the temperature is cooler, SCOBY growth will still be present but may be much thinner. It can also take longer for the brewing cycle at this time of year.
What it can look like:
All normal.
The top culture forms because Kombucha is primarily aerobic during first fermentation. The surface is where oxygen meets liquid — prime real estate for new growth.
✅ Healthy sign: A new layer forms within 3–10 days (depending on temperature).
Kombucha fermentation is basically a transformation arc:
Sweet tea → slightly tangy tea → balanced Kombucha → tart Kombucha → Kombucha vinegar
Taste is the most reliable “health check” there is.
✅ Healthy sign: Each tasting shows progress.
If you taste at day 7 and it’s exactly as sweet as day 1, fermentation may be stalled (often temp-related).
This is the part that freaks people out — and it shouldn’t.
Since the culture is a symbiosis of both bacteria (the SCOBY itself) and yeast (the brown strands), it is important that both are in balance.
In the early stages, before the culture has fully formed, you may notice yeast congregating at the top of your brew. They look like brown strands or clumps (or a brain!) that eventually attach themselves to the underside of the culture or fall to the bottom of the vessel when they expire. Some confuse the yeast blooms for mold because beneath the newly forming culture they may look bluish or black.
Again, balance is key – so you want to have some yeast, but not too much. For that reason, it is important to always use starter liquid from the top of your brew where it is bacteria rich. Only using starter from the bottom of your vessel may result in “beery” Kombucha.
Check out this article on achieving carbonation in Kombucha if you suspect yours is out of balance.
A healthy Kombucha brew often contains:
That’s usually yeast doing its job.
Yeast helps break down sugar and produces compounds that bacteria then convert into acids. It’s a symbiotic relationship.
✅ Healthy sign: You see some yeast activity and normal sediment.
If your brew becomes extremely yeasty (thick sludge, harsh smell), that’s not necessarily unsafe — just unbalanced. It can usually be corrected.
One of the Kombucha culture’s most important defense mechanisms is its low pH. The average pH of properly fermented Kombucha tea is 3.2-2.5. The high acidity prevents other potentially harmful microorganisms from colonizing the culture. In fact, the bacteria and yeast work so well together, that they kill other harmful bacteria on contact. Although making Kombucha at home seems daunting, it is actually quite safe.
Pro Tip: Use a pH meter to monitor your brew’s progress. However, pH will not indicate that your brew is ready to drink as it will often reach the desired pH within the first 3 days of brewing. Therefore, you need to use your taste buds to tell you when your brew is ready. Remember, the longer it ferments, the more sugar is converted and the tarter the flavor. Bottle conditioning will mellow the flavor.
Let’s be very clear:
Mold is fuzzy.
It can be:
It typically appears as distinct fuzzy patches on the surface.
✅ Healthy SCOBY growth looks:
If you see fuzzy mold, discard the brew and do not taste.
👉 Head to our Kombucha Mold Gallery for the largest collection of examples on the web
Normal. A SCOBY can float, sink, tilt, or hover mid-jar. The new culture still forms on top.
Normal. Texture varies based on temperature, tea type, and microbial activity.
Usually yeast staining. Normal.
Often a sign of active fermentation and CO₂ production. Normal.
Often the start of a healthy new layer. Normal.
These aren’t automatically “bad,” but they warrant troubleshooting:
These are often fixable through:
Often 3–10 days depending on temperature and starter strength. Cooler environments take longer. Find more details on our How To Brew Kombucha page.
Usually yes. SCOBY position doesn’t determine health. A new layer will form at the surface either way. Learn more about SCOBYs here.
No. Brown strings are usually yeast. Mold is fuzzy and dry-looking on the surface.
Tangy, slightly vinegary, tea-like, sometimes lightly fruity or yeasty — but not rotten or putrid.
If it’s clean but too sour, it’s usually safe but may be more enjoyable diluted, used in recipes, or turned into Kombucha vinegar. Check out our page on Kombucha Vinegar to learn about what you can do with this versatile ingredient.
Healthy Kombucha doesn’t always look “pretty.” It looks alive.
If your brew:
…you’re on track.
And if you want to sprinkle in hopes, wishes, and a tiny bit of reverence for your culture while it works its magic?
We fully support that.
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