The Dangers Of Kombucha Tea (And How to Avoid Them)
Kombucha tea has been used for thousands of years to improve health (read how to make it yourself). Kombucha helps regulate your body’s digestive system, it promotes better immune system functioning, and it provides essential amino acids that help keep the very cells of your body in better repair. There are many very real benefits of drinking kombucha tea that have been documented in personal stories and scientific studies alike.
However, there are also risks associated with drinking kombucha that are related to the way it’s brewed and the way it’s consumed. To make sure that you get all of the good from kombucha without any problems, you need to:
- follow the proper techniques for brewing kombucha tea
- know how to safely prepare kombucha for short-term and long-term storage
- be aware of the effects of kombucha tea on your system
Yes, there’s a lot of nasty pathogens that can make you sick, but the good news is the organic acids produced by the action of the SCOBY (the Symbiotic Colony Of Bacteria and Yeast) create a low-pH environment that destroy and drive off many of the pathogenic bacteria and toxic molds that can contaminate foods and beverages. Properly-brewed kombucha has a pH of between 2.5 and 3.5 depending on the kombucha brewing time during the primary fermentation, as well as the types of ingredients and methods you use, especially during bottling and second fermentation. Research using kombucha tea shows that when the pH of a liquid is below 4 then many of the harmful bacteria found in foods will not survive. What’s more, the anti-microbial action of the compounds in fermented kombucha tea also fight off these invaders.
Here are just some of the food-borne pathogens that acidic kombucha can help destroy:
- Staphylococcus aureus (food poisoning, sinusitis, skin rashes)
- Escherichia coli (food poisoning, gastroenteritis)
- Campylobacter jejuni (gastroenteritis, food poisoning)
- Salmonella enteritidis (food poisoning, fever)
- Listeria monocytogenes (meningitis, food poisoning)
It takes several days for the SCOBY microorganisms to ferment enough of the sweetened black tea to produce the organic acids like acetic acid that help with this protection. That’s why it’s important that you add concentrated kombucha tea or distilled white vinegar as your starter liquid (i.e. ‘the Kombucha starter’), so that the tea in the brewing container has a lower starting pH. In general, it will take between 5 and 10 days to get a pH of 2.5, depending on the temperature of your brewing container and the health of your SCOBY.
NOTE: You can test the pH of your tea as it ferments using pH test strips or an electronic pH meter.
Mold and Airborne Yeasts Risks
Mold compromises the health of your SCOBY, even if it’s not a type of mold that will create a health risk for you. If you suspect that your SCOBY is moldy then you may need to throw that SCOBY away. That’s why it’s a good idea to always have back-up SCOBYs in your SCOBY hotel.
If you do have mold contaminating your SCOBY, it will be fairly easy to identify. Mold is fuzzy, grows in rings, and is usually pure white, or black, blue, or green.
It’s quite rare, provided your container is clean and you have covered your kombucha vessel with a breathable cover (papertowel, coffee filter, cloth), to get an infestation of mold. But, if there are any cracks or holes in the material covering the brewing kombucha or it’s not tightly woven enough (like cheesecloth), then it’s possible for mold or wild yeasts to penetrate it still.
There are many other microorganisms floating around your brewing space that can harm the SCOBY, like wild yeasts. A healthy SCOBY should be able to fight these off, but if your SCOBY has become out of balance, the native yeasts might be vulnerable. Some of these yeasts will cause the SCOBY to start drying and flaking on the top surface. Other yeasts will not make the SCOBY change in appearance, but you’ll notice a strange flavor in the fermenting tea.
The best way to keep airborne molds and yeasts from your brewing container and SCOBY is to make sure that the cover is made of a tightly-woven material that keeps them out. You can use an old t-shirt, a cotton handkerchief, a linen kitchen towel, or any other material that you can tie or secure tightly around the mouth of the container. Some people use unbleached coffee filters (basket, not cone) or even paper towels. Be sure that there are no gaps or holes where molds and insects can get in to the liquid.
The location WHERE you put your kombucha brew can make a difference. We’ve heard stories from fellow brewers they’ve experienced mold infestations when putting the brewing kombucha near fruit (especially rotting fruit) or garbage cans. These locations might have a lot of mold growing on and around them, which may spread to your kombucha.
The acidic fermented kombucha tea will wear away some types of material, like metal, paints, and ceramic glazes. This is why you need to only use stainless steel when brewing, fermenting, and storing kombucha. This includes lids as well as containers. If you are using glass canning jars to brew or store your kombucha tea, you need to replace the metal caps and rings with plastic screw-top lids. If you use recycled glass bottles, make sure they have plastic lids, not metal caps.
Brewing and storage containers that are painted or glazed should be avoided. Many containers are lined with lead-based glazes and the toxic lead will leach into the kombucha tea.
Be careful when adding extra flavoring ingredients to your kombucha. Fresh and dried fruit can contain or attract mold, and other ingredients like nuts and whole spices may be contaminated by bacteria and mold that you cannot see. Normally, if you have the right pH in your kombucha tea, you won’t have a problem with extra ingredients, but keep an eye on the tea to watch for possible mold developing on the surface of the liquid or the sides of the container.
Be sure to use filtered water when brewing kombucha. Unfiltered tap water may contain toxic bacteria (if it comes from from a spring or well) and municipal tap water generally contains chlorine, which will kill the SCOBY. If your SCOBY is harmed, it won’t produce the acids required during fermentation, and drinking the kombucha tea may present health risks.
Poor Sanitation Risks
Mold buildup often happens when equipment isn’t cleaned regularly. It’s a good idea to scrub all of the equipment you use for making the sweetened tea (pots, spoons), transferring the tea between containers (ladles, siphons, funnels), and preparing the extra ingredients (cutting boards, knives, measuring cups) with mild soap and hot water. Rinse them with filtered water, and do a final rinse with white distilled vinegar before letting them air-dry and storing them in a closed container to keep out dust and bacteria.
Keeping your jars and bottles clean is important because leaving residue from previous batches will attract the molds and bacteria into the containers, and when you pour your fresh brewed kombucha tea into the containers, it will be contaminated. Use a bottle brush to get to all of the corners and cracks in your equipment, and rinse well with distilled white vinegar.
Make sure your hands are always clean when you’re making kombucha tea, especially when you’re handling the SCOBY. Dirt and bacteria hide under your fingernails, and anything that you’ve touched which is contaminated (like a piece of cheese with mold on it) will leave traces on your skin. These bacteria often cluster underneath jewelry like rings, so remove your rings and scrub your hands well each time.
To avoid any cross-contamination, separate your kombucha equipment if you can. Don’t use the same spoons, cutting boards, and containers that you use for doing your regular cooking.
Pest Risks (Insects)
If you keep your brewing container tightly covered with closely-woven material, you generally will not have any problems with creatures invading your tea space. However, there are three types of bugs that can create a problem for kombucha brewers:
- fruit flies
- vinegar nematodes
While these bugs don’t generally create any health risks, you probably don’t want to drink kombucha tea that’s full of dead ants or fruit fly eggs, and the nematodes will colonize your SCOBY, making it unusable.
Ants can be persistent pests, and even if you have your container covered securely, they may still sense the sugars in the tea or on the counter. Even one grain of sugar can attract an ant, and where one is, hundreds will usually follow. Ants, especially small ones, can often find a way under your cloth mesh covering and into your Kombucha, so beware.
If you have a problem with ants in your brewing area, keep all surfaces clean and store your cleaned and dried equipment and utensils in a closed area if possible.
To protect your brewing container, you can place it in a shallow pan of water. The ants will not be able to cross the water to climb up on the container.
Like ants, these flying pests are frequently found in kitchens around the country, especially in the summer. You can reduce the chances that fruit flies will find your kombucha tea by keeping your kitchen clean, getting rid of any overripe or rotting fruits and vegetables, and cleaning your trash can and compost container regularly. The flies will lay eggs in the tea and on the SCOBY if they get a chance, and you’ll end up throwing both of them out.
A nearly invisible creature called Turbatrix aceti occasionally makes an appearance in home-brewed acidic liquids like kombucha and vinegar. It doesn’t mind the low pH of kombucha tea – in fact, it loves it. These small worm-like creatures aren’t harmful, but most people don’t enjoy drinking or using kombucha tea if there are little things swimming around in it. Because they will colonize the SCOBY, you’ll have to toss out the SCOBY as well as the kombucha tea to get rid of them.
Vinegar Nematodes are highly unlikely to infest your kombucha if you are home brewing on small scale. It’s only large, industrial-sized or commercial operations that are most at risk from these worms. Still, some kombucha homebrewers have reported finding a vinegar nematode infestation, so the risk is there, however small.
Overconsumption of Kombucha
Too much of a good thing is still too much, and if you’re new to kombucha, you need to make sure you’re not shocking your system by starting out with large amounts of kombucha tea. Most experts advise that you start with one ounce of kombucha per day to see how well your system tolerates it, before increasing your daily dose. Remember, kombucha is a powerful anti-oxidant that regulates your digestive system. If your immune system and/or your digestive system is out of balance, simply drinking kombucha will create a physical effect as your body works to flush out toxins.
Here are some of the symptoms people have reported experiencing while they have been slowly adjusting to regular use of kombucha tea:
- muscle cramps
- sinus problems
- skin rashes
Most of the time these are temporary. As your body uses the probiotics and nutrients in kombucha tea to reestablish a healthy balance and purge your system of toxins, these symptoms should clear up. It will help if you drink plenty of water to make it easier for your body to flush the toxins from your system. You should also get plenty of rest so that your body has the resources it needs to move you through what many professionals refer to as the “healing crisis” caused by kombucha tea.
NOTE: If any symptoms continue for more than a week or two, or if you have any other concerns about the effects of kombucha tea, you should consult a medical professional such as your doctor, a naturopath, or a dietician.
Drug Interaction Risks
If you are taking any prescription drugs, you should talk to your doctor before starting to drink kombucha tea regularly. Medication prescribed for blood pressure, high cholesterol, or other circulatory or heart conditions may be affected by the action of kombucha on your immune, circulatory, and digestive system.
Kombucha During Pregnancy and Nursing Risks
The probiotics in kombucha can help support mother and child during and after pregnancy. However, you need to be absolutely sure that there is no problem with invasive yeasts, molds, or bacteria that could pose a health problem.
Kombucha and Children Risks
Honey is one of the types of sugars for kombucha that many people use during both primary and secondary fermentation. If you use honey, especially raw honey, it’s a good idea to keep the fermented tea away from younger children, and to not drink it yourself if you’re nursing. A strain of bacteria called C. botulinum has been linked to botulism in infants and can cause constipation, weakness, and even death.
There is no scientific proof that kombucha itself is bad for children 5 years old and younger, but because it’s a fermented food that contains yeasts and bacteria, it should be treated with caution. In general, you can think of kombucha as being like home-made sauerkraut or pickles, or raw milk or raw milk yoghurt. Children do not have fully developed immune systems, and if the kombucha has even low levels of toxic bacteria, they will be more vulnerable.
If you are especially concerned for your children (or yourself) about potential pathogens in Kombucha, then you can kill all pathogens in kombucha by pasteurize it. Of course, this also kills off the yeasts and bacteria from the SCOBY colony, so you will lose some of the probiotics in the kombucha tea. However, most of the nutrients and organic acids are still in the tea, still making it a healthy beverage for people of all ages though without the probiotic effect.
How to Pasteurize Kombucha: To pasteurize kombucha, heat the kombucha tea to 145F and keep it at that temperature, stirring constantly, for 30 seconds. Carefully pour the kombucha into hot sterilized glass bottles, seal the bottles, and let cool.
NOTE: You can sterilize glass bottles by putting them in an oven and heating to 200F for 20 minutes, or by putting the bottles in a large pot of water, bringing the water to a boil, and boiling for 10 minutes. With either method, turn off the heat, and leave the bottles in the closed oven or hot water until ready to fill.