Kombucha is a tasty and healthy drink that you can find at pretty much any grocery store. But some people worry about whether or not it's safe to drink when it’s homemade?
While homemade kombucha has a small risk of bacterial or mold contamination and high alcohol content that may make it unsafe to drink, these things can be avoided with proper brewing methods and techniques, making homemade kombucha generally safe to drink.
In this article, I’ll not only cover some of the safety concerns you may have about homemade kombucha, but also give you the solutions to be able to keep these things happening in your own home brews. Lets get started!
What is Kombucha?
Kombucha is a probiotic drink made from fermented tea that has become quite popular in recent years due to its great taste and many health benefits such as improved digestion and gut health, detoxification, and immune system strengthening.
While most people buy it in store, kombucha can be brewed at home at a much cheaper price, which is nice for those who drink it often.
What Can Make Homemade Kombucha Unsafe?
Risk of Bacterial or Mold Contamination
The first thing that may cause homemade kombucha to be unsafe to drink is its risk of contamination. By contamination I mean any bacteria or mold growth inside of the kombucha that if consumed would be dangerous to your health.
The risk of bad bacteria and mold growth is much higher in kombucha than it is in drinks like sodas or juices because kombucha already has a living culture of made good bacteria and yeast in it, and the process of feeding them and keeping them alive provides the perfect environment for bad bacteria to grow as well if they were to begin growing.
The danger of contamination is even higher in homemade kombucha than store bought because most people's kitchens at home are not as sterile as the commercial kitchens used by kombucha brands. Plus at home brewing processes arn't as precisely calculated or closely observed as a large company that’s brewing thousands of gallons of booch a day.
A kombucha that developed mold or unhealthy bacteria could make anyone sick, but would be especially dangerous for those with immune diseases or other similar pre-existing conditions.
Now the risk of homemade kombucha becoming infected with bad bacteria is real, but it’s far from inevitable. Lets talk about the simple steps you can take to ensure you’re homemade booch is doesn't get contaminated and is always safe to drink.
Preventing Bacterial Growth in Homemade Kombucha
The first thing that you should always do to mitigate the risk of contaminating a homemade batch of kombucha is keep everything around it as sanitary as possible.
That means washing equipment in between uses and making sure there’s no leftover soap residue on it that could harm the the living bacteria culture that ferments kombucha known as the SCOBY (Symbiotic Culture of Bacteria and Yeast)
It also means washing your hands well before every time you touch the SCOBY, and touching it as little as possible. She’s a sensitive creature.
Another important thing you need to do if you don’t want bacteria forming in your homemade kombucha is brew it in a safe, non corrosive material like glass, stainless steel, or wood.
Materials like plastic and metal have dangerous BPAs and chemicals that can dissolve off in the highly acidic kombucha and not only ruin or kill the SCOBY but also make the drink unsafe for you to drink.
On top of this, plastic can get scratched during the brewing process and bad bacteria can grow protected in the crevices that form.
You can get a 2 pack of 1 gallon glass jars for like 20 bucks on Amazon here. Just use these or another glass container instead of plastic and you’ll exponentially increase the safety of your homemade kombucha.
Also make sure the container is always covered with a rag or cheese cloth secured with a rubber band to keep any fruit flies or food from getting inside.
Preventing Mold Growth in Homemade Kombucha
If mold develops in your kombucha you not only risk getting sick by drinking it, but your entire brew, including the SCOBY is ruined and needs to be thrown out and replaced.
Below are a few rules that if you follow correctly will almost insure mold never grows in your booch.
One of the best ways to keep mold out of your kombucha is by brewing it within the correct range of temperatures. Kombucha is brewed ideally at a temperature of 75-78 F(24-26 C) but it can be made anywhere from 65-85 F (18-29 C).
If your brewing kombucha gets below 65 degrees, the living bacteria culture that ferments it becomes slow and lethargic. This oftentimes leads to mold growth because it’s these bacteria and their high production of acids at normal temperatures that fight off mold.
So if the kombucha is being brewed at too cold of temperatures, it will be less acidic and much more vulnerable to being contaminated and ruined by mold.
A similar way to keep mold away is to make sure you use enough sugar and starter tea.
Using the right amount of sugar (1 cup per gallon of booch) will ensure the SCOBY has enough food to be active and produce the acids that prevent mold.
And starter tea, which is just kombucha from a previous brew added at the beginning of a new one, gives the booch some acidity at the beginning of the brewing cycle when it’s most vulnerable to being ruined by mold.
If you want a more in depth look at mold and how to keep it out of your kombucha, you can check out my article “What SCOBY Mold Looks Like and How to Prevent it” here.
As long as you follow your kombucha recipe well, use the right amount of ingredients, and follow the tips above you shouldn’t have a problem with mold in your homemade kombucha. But if you want to be sure you’re kombucha is acidic enough to fight the mold, you can use pH strips like these to check its acidity
After 7 days of fermentation the kombucha should ideally be between 4.2 and 2.4pH. If it’s higher than this your booch may be at risk for mold.
The SCOBY and brewing kombucha are a weird looking thing, so it can be hard to tell what’s mold and what’s normal bacteria and yeast.
A few key characteristics of mold that you can look for in your kombucha are:
1. Mold always grows on the surface
2. Mold’s texture is dry and fuzzy
3. Mold develops in circles
4. Mold is an interesting bright color (white, green, blue black)
Risk of High Alcohol Content
Besides contaminants, the other thing that can lead to homemade kombucha being unsafe is a high alcohol content.
All kombucha has at least a small amount of alcohol in it as a natural result of the fermentation process. Kombucha you buy at the store, unless it’s specifically marketed as “hard kombucha” will have under a 0.5% alcohol content because this is the federal limit for a drink to be considered nonalcoholic and be sold to minors.
While this level of alcohol in store bought booch is pretty much insignificant (it’s about the same amount as a ripe banana or grape juice), home brewed kombucha’s alcohol level can be much higher.
Because home brewed booch is not as tightly regulated nor consistent batch to batch, the amount of alcohol in it can get up to 3.0%. For reference most beers are 4.5% and hard seltzers 5.0%
A homemade kombucha with a 3% alcohol level, almost that of a beer, could be dangerous for groups such as pregnant women, children, and recovering alcoholics.
How to Keep Your Homemade Kombucha Low in Alcohol
If you or someone you know who wants to drink homemade kombucha is in a group that can't drink alcohol, there is a way to ensure that your homemade kombucha stays below 0.5%: a hydrometer.
Now I know it doesn’t sound exciting, but hydrometers are actually a really cool tool you can use when making anything with booze in it.
Basically the longer your kombucha ferments, the more alcohol is produced and is in the final drink. A hydrometer gives you a reading of the amount of alcohol in your kombucha so you can stop the fermentation when it gets to 0.5%
I found a really affordable and high quality hydrometer kit that includes a hydrometer, test jar, protective case, cleaning brush, storage bag, cleaning bag, and instruction sheet. Plus it has free shipping! If you’d like to know the alcohol content of your home brewed kombucha you can find that kit on Amazon here.
Also, if you’re trying to avoid kombucha high in alcohol, make sure to refrigerate it when it’s finished brewing. If your kombucha is stored at room temperature the bacteria will continue to ferment the sugar into alcohol. Refrigeration slows down the activity of the bacteria culture, therefore slowing down fermentation and the production of alcohol.
So what’s the takeaway here? Is homemade kombucha safe?
Well I think we can see, after looking at the concerns of bacterial and mold contamination and high alcohol content, that while there are certain risks with home brewing kombucha, they can be mitigated or completely prevented when the drink is made correctly.
If you’d like to learn more about how to safely make kombucha at home be sure to check out the rest of my website! I have tons of guides, tips, and reviews that will help anyone, from beginner to advanced, get better at home brewing kombucha!