What Does A Healthy Kombucha SCOBY Look Like?
The kombucha SCOBY (the Symbiotic Colony Of Bacteria and Yeast) is a collection of living organisms that work together to process the nutrients in sweetened tea and create a fermented liquid full of probiotics and vitamins. Because the colony is alive, the appearance of the colony will change slightly over time. In addition, every colony is different, and there are variations in texture, shape, and color depending on where the SCOBY came from, what type of kombucha tea you’re brewing, and even the environment you’re living in and the seasonal changes that alter the temperature and humidity in your kitchen.
If you think about it, a kombucha colony is like a person, and the way it looks is determined by its genetics as much as its upbringing. For example, whether a person has blue eyes or brown eyes doesn’t really change how well they see, so the fact that people in Japan tend to have brown eyes and people in Scandinavia tend to have blue eyes doesn’t say anything about average eyesight in those two regions. However, when a person with brown eyes develops cataracts, their eyes can appear to turn blue. When you’re brewing kombucha at home you need to learn to tell the difference between healthy blue eyes and unhealthy blue eyes. (Metaphorically speaking, that is. The SCOBY may look like a creature from outer space, but it doesn’t have eyes. And if it does develop eyes, you’ve either got the makings for a horror movie in your kitchen or a chance to win the Nobel Prize.)
Once a SCOBY has reached the edges of its container, it will start getting thicker. As long as there’s enough food for the SCOBY in the liquid it’s in, it will keep growing.
When the SCOBY is colder, the action of the yeast and bacteria slows down and may even stop. That’s why most people recommend keeping your storage and brewing containers at room temperature, to keep the SCOBY active. However, if you need to take a break from brewing kombucha you can use a lower temperature to put the SCOBY on hold for a while.
If you’re growing a SCOBY from scratch remember that it takes time for a SCOBY to develop. Depending on your environment and the temperature, this could take up to a month, and maybe even longer. The best temperature for the SCOBY is between 70-80F and if the container is cooler, the SCOBY will take longer to thicken up. There are some easy ways to keep a SCOBY warm enough but be sure you don’t overheat the container, because this will also cause problems that will affect the quality of the kombucha and the health of the SCOBY.
You will usually get the best results from a SCOBY that is at least 1/8 to 1/4 inch thick, though thinner SCOBYs can also produce a good brew.
SCOBYs generally stay resting fairly flat at the top of the liquid in the container, but they might tilt into the liquid at one edge, sink below the surface of the liquid, or even sink down to the bottom of the container. Depending on how saturated the liquid is (the amount of nutrients, minerals, and other compounds in the water) the SCOBY will sink or float, according to whether the colony is denser than the liquid or lighter. A SCOBY that has drifted to the bottom of a container will usually make its way back up to the top, as the colony consumes the nutrients from the liquid it’s in.
A healthy SCOBY has a texture like soft rubber. It’s flexible but firm, and holds together well. If your SCOBY is brittle and falls apart when you try to lift it out of the liquid, it’s probably a good idea to throw it away.
Healthy SCOBYs are slightly damp, and need to stay damp to stay in good shape. If your kitchen is very dry, you might see dry or scaly patches on the top of a SCOBY, but if you make sure to keep enough sweet tea and kombucha mixture in the container, the SCOBY should be fine.
A kombucha SCOBY will naturally take the shape of the container it’s in. The colony will expand across the top of the liquid until it reaches the edges, and then will start growing horizontally (making it thicker) instead of vertically (because it can’t get any wider). Since most people use round containers for brewing kombucha most SCOBYs end up being round.
However, even round SCOBYs vary in shape. The edges might be a little ragged, or smooth and clean. Ragged edges are often caused by bubbles of carbon dioxide (CO2), a natural byproduct of fermentation, that seep up along the edge of the SCOBY. Sometimes the bubbles will go right through a thin baby SCOBY, leaving holes in the middle. This is nothing to worry about – the SCOBY will grow back together.
SCOBYs are generally smooth on top, but there might be lumps where the colony is growing unevenly. There might be larger clusters of growth on one edge or the other. Sometimes these clusters separate from the main SCOBY and then join up again.
Underneath the SCOBY you’ll probably see strings and strands of brownish material. These are yeast clusters, and they’re perfectly normal.
SCOBYs come in many colors, though generally they’re a light white, yellow, or cream color. Sometimes they’ll be more tan or orange, or even brown. The color of the SCOBY can be affected by the type of tea you use, so don’t be surprised if you end up with a blushing SCOBY after experimenting with adding hibiscus flowers to your tea!
The colors to watch out for are dark brown and black. When the SCOBY is not healthy, it will often get very dark, and a dead SCOBY will turn black. If you’re not sure about the overall age and health of your SCOBY, it’s a good idea to throw it away and start using a new one from your SCOBY hotel.
A few dark patches aren’t anything to worry about, if they’re light to medium brown – essentially the same color as the yeast strands underneath the colony. This is likely due to strands of yeast that have gotten caught between the layers of the SCOBY as it thickens.
Some color changes are due to invasive mold developing on the SCOBY, but these are easy to tell from normal color variation.
Is Your SCOBY Moldy?
The biggest danger to your SCOBY is mold — but mold is quite rare if you brew your kombucha in sanitary conditions. Still, it’s always best to know what a moldy SCOBY looks like so you can stop the process if it ever happens. This is the one condition where you could make Kombucha that is toxic and dangerous to your health.
How to Tell Mold on Your SCOBY
If you see fuzzy or “hairy” spots that form circles or rings on top of the SCOBY, it’s very possible (indeed, very LIKELY) that this is mold.
I’ve written a 2000 word article just to help you figure out if your Scoby has mold or not. Read it.
Mold will form these fuzzy clumps, while at the same time drying out the surface of the SCOBY beneath. Mold can be any color, but is usually green, black, white, or blue. Mold will only grow at the top of a SCOBY, because the particular microorganisms that make up invasive mold require oxygen to grow.
In general, mold will only form if your SCOBY is not healthy. If you see mold on your SCOBY, throw it out and start over with a new one. You’ll need to dump out the liquid in the container as well, because it may have gotten infected.
Make sure to read the following articles we’ve written about Mold and Kombucha
- How to Figure Out if Your Scoby Has Mold
- What to Do if Your Scoby has Mold on It
- How to Prevent Mold from Growing in Your Kombucha