A healthy and active SCOBY is one of the most important parts of making a good home brew of kombucha. But what if you’re SCOBY hasn’t been doing what it’s supposed to and you think it might be inactive or dead? How can you tell if a SCOBY has died, and what kinds of things can cause a SCOBY’s death?
If a SCOBY is not producing a vinegary odor, bubbles, and/or not creating new strains of yeast and baby SOBYs on the surface of the kombucha, it may not be fermenting properly and could be dead. SCOBYs are tough creatures that don’t die often, but if they are in temperatures below 65 degrees F, are shocked by a quick temperature change, get moldy, or don’t have enough food, they could die.
As a kombucha home brewer myself I understand that it can be tough to understand the condition of your SCOBY simply because of how weird and unique they look. In this article I’ll attempt to clear up any confusion about the status of your SCOBY and get you the information you need to determine whether or not it’s dead.
What Exactly is a SCOBY?
If you’re reading this article, you probably already know that SCOBY stands for Symbiotic Culture of Bacteria and Yeast and is a living culture of bacteria and yeast that ferments sweet tea into kombucha.
What you may or may not already know, is that the SCOBY isn’t just that jelly like disk that sits on top of the brewing kombucha, it actually includes all the bacteria and yeast floating throughout the entire kombucha brew.
The disk or “mother” that floats on top of the kombucha is actually known as the “pellicle” and is just a mat of cellulose (a bunch of sugar strung together) produced by the SCOBY floating in the kombucha.
So SCOBY technically = the floating jelly disk known as the pellicle + all the small pieces of bacteria and yeast floating throughout the kombucha.
How to Tell if Your SCOBY has Died
The thing about SCOBYs is that because they are living, each one looks and grows differently. You may have a SCOBY that looks white and smooth while your friend may have a SCOBY that looks dark and rough. And both are healthy and make great kombucha.
So if your SCOBY hasn’t been moving much lately and you think it could be dead, here are some universal identifiers that you can look for to determine its health.
Signs that a SCOBY is Living
Fermentation with a Vinegary Odor
First, the most obvious one. If your SCOBY is producing kombucha, it’s still alive.
Although this seems obvious, some people are quick to assume that their SCOBY is dead when it’s actually just fermenting slower than normal. A slower fermentation is common especially when you brew in colder environments (less than 70 degrees F) and during the SCOBYs first fermentation right after you bought it.
To confirm that your SCOBY is alive and just fermenting slowly rather than dead, check the taste of your brew every day. If the SCOBY is working the sweet tea will taste more and more bitter as time goes on, even if the transition is slow.
You can also tell that your SCOBY is fermenting properly if the kombucha brew is giving off a vinegary odor.
One of the products of the SCOBY’s fermentation of kombucha is carbon dioxide (CO2). CO2 is a gas in drinks like soda, sparkling water, and kombucha that produces bubbles and gives them carbonation.
This means that seeing CO2 or bubbles in kombucha can be a sign that the SCOBY is alive and fermenting properly.
Baby SCOBY and Strings of Yeast Growth
Just like every other living thing, if your SCOBY is alive it’s gonna grow. Active SCOBY’s will begin to create thinner baby SCOBYs that will take the shape of the opening of the container. These new SCOBYs will increase in thickness over time, but even seeing a really small and thin one beginning to appear is a good sign that your SCOBY is working.
Active SCOBYs will also grow strings of yeast so keep an eye out for those too.
Just Because the SCOBY Sank Doesn’t Mean It’s Dead
Many times when people worry about whether or not their SCOBYs are dead, it’s because it sank to the bottom of the brewing vessel and they think a sunk SCOBY means it’s dead.
But the truth is: SCOBY LOCATION DOESN’T MATTER
One more time: SCOBY LOCATION DOESN’T MATTER
Remember, the disk shaped pellicle is only part of the SCOBY, so it doesn’t really matter whether it floats or sinks, because little pieces of bacteria and yeast should be all throughout the kombucha anyway.
What determines whether a SCOBY floats or not isn’t whether or not it’s alive, it’s the density of the collagen layers and how many CO2 bubbles are being produced by the yeast to lift it up.
Things that can kill a SCOBY
Now that you know what to look for to determine if your SCOBY is dead or alive, let’s talk about a few things you can be aware of when making your kombucha to keep from putting the health of your SCOBY at risk.
Too cold of temperatures
SCOBYs have an optimal range of temperatures in which they can survive, stay healthy, and ferment your kombucha. This range is around 65 degrees F (18 C) to 85 degrees F (29 C).
If your SCOBY is in an environment below 65 F, it could become slow, inactive, and even die. So if you live somewhere that gets cold like it does here in Michigan, be aware of the temperature of the room you're brewing kombucha in.
And if you’d like to learn a few ways to keep your SCOBY warm in a colder environment, you can check out the article I wrote on kombucha temperature here.
Too hot of a Temperature Shock
On a similar note, if you’re SCOBY gets too hot, it can get damaged or possibly die. While it’s not likely that the room your fermenting kombucha in will ever reach above 85 degrees F (29 C), it is possible to heat shock your SCOBY by adding it to brewed tea before it’s cooled off to room temperature.
If you want to learn about what causes a SCOBY to become moldy and how to best prevent your kombucha from getting contaminated, I recommend checking out the article I already wrote on it, “What SCOBY Mold Looks Like and How to Prevent it,” here.
A quick synopsis is that if you don’t brew your kombucha at the right temperatures, with clean equipment, and at a high acidity, it could become moldy. And once even a little bit of mold gets into a kombucha ferment, you have to throw the entire SCOBY away. Which is a very sad thing to do.
Not Enough Food
The last thing that can kill a SCOBY, and one of the most obvious, is malnutrition, or not having enough food.
Just like you and me, the SCOBY needs food to eat for energy so that it can turn sweet tea into fizzy and tasty kombucha.
The “food” that the SCOBY eats is the sugar in the sweet tea. Which means that if you don’t use enough sugar in your kombucha recipe, or leave the SCOBY alone without supplying it any sugar for an extended period of time, it will eventually die.
To avoid starving your SCOBY make sure to use 1 cup of sugar per gallon of kombucha when brewing and if you’re storing a SCOBY on the side be sure to give it some sugar at least once every 8 weeks.
SCOBYs are tough and resilient creatures that don’t die easily. However, if you fail to take care of a SCOBY by not storing it within 65-85 degrees F, shocking it with temperature changes, not protecting it from mold, or not feeding it enough sugar, you could kill it.
No one wants to kill their SCOBY, especially if you’ve been growing it for an extended period of time. So take care of her by following some of the tips in this article and she’ll continue to make you great tasting and healthy kombucha!
If you’d like to learn more about SCOBYs and kombucha, be sure to check out the rest of my website!
Have a great day!