WHAT IS KOMBUCHA?
Simply put, it’s fermented tea. To ferment it, we use sugar and a culture known as a SCOBY (Symbiotic Community of Bacteria and Yeast). People drink kombucha because they like the taste, or because it makes them feel really good to drink it. Some people ascribe miracles to this tasty tonic. No need to buy the hype. Drink a bit and see how it makes you feel!
There are a variety of ways to make kombucha. The gist of it is you add a SCOBY to room temperature, sweetened tea with a little bit of finished kombucha in it. In a few days (or weeks, depending on your sour/sweet preferences), you have kombucha! Here are two basic recipes to get you started:
Single Batch Kombucha – Make one batch at a time. With this method, you drink the entire amount you’ve brewed (minus the bit you need to start your next batch). This option is great if you drink kombucha infrequently or if you like to experiment with different sugar and tea sources.
Continuous Brew – Have fresh kombucha every day. A continuous brew system needs to be fed on a regular schedule, but other than that it is extraordinarily hands-off. Clean your vessel every several months and remove excess SCOBY when you do. It can be bottled and flavored after you draw it off. This works well for people that drink kombucha in consistent amounts. (I mostly brew Continuous these days.)
STARTER (AKA STARTER TEA, AKA FINISHED KOMBUCHA)
Starter tea is simply finished kombucha. You can get finished kombucha from a friend who brews, use grocery store (preferably plain) kombucha, or substitute the starter tea with an equal amount of distilled white vinegar (ideally not “living” vinegar which may change the microbial make-up of your brew. That could be fine, but it could change the balance of your yeast and bacteria, so better to stick with plain stuff) . The point of the starter is to inoculate the drink with all of the microbes that make kombucha kombucha, but also to provide acidity at the start of fermentation. Acidity is what makes kombucha safe to consume, so don’t skip this. Distilled vinegar will not contain the needed microbes, but no worries—the SCOBY will do that job!
THE KOMBUCHA CULTURE (SCOBY, MOTHER, MUSHROOM, PELLICLE)
Let’s just get this out of the way: SCOBYs are crazy. I dig their funkiness, but I totally get how people are freaked out by them. They’re slimy. They’re blobs. And they seem to appear out of nowhere. If you weren’t familiar with kombucha, you would likely assume that something very horrible was growing on your liquid. Ease your minds. It’s just microbial creatures using nutrients from your sweetened tea to build a cellulose home and grow their own ranks!
There are a whole bunch of microbes involved in SCOBY (and kombucha) production. In fact, there is a lot of variation from SCOBY to SCOBY. If you look at all of the available literature on the microbes in SCOBYs, you’ll find a great deal of variation. These microbes work together. The yeast consumes the sugar and the bacteria eat the byproduct of the yeasts’ feast (alcohol, among other things) and turn it into a host of things (including vitamins, unique compounds and a few kinds of acid, and more).
True kombucha comes from tea, the Camellia sinensis plant. Look for unflavored white, green, oolong, pu-erh or black tea.
I have had success with brews from tisanes (what we in the US call tea, but which are actually drinks brewed from a variety of other plants, including chamomile and rooibos) and flavored teas (including Earl Grey). Over time, though, SCOBYs I’ve brewed in Camellia sinensis tea have, on the whole, remained stronger and produced a tastier brew. I’m sure there are culturally varied SCOBYs out there that have adapted to other plants and will do just fine, but to find out if your SCOBY is one of those, it’s always best to test with a spare SCOBY (believe me, you’ll have them) for a least 5 batches before switching all of your SCOBYs to a non-Camellia sinensis drink.
I enjoy adding tisanes and flavored teas to my kombucha for secondary fermentation, after the SCOBY has been removed.
I have had my best results using cane sugar. I use a high quality, organic, fair trade cane sugar, but it is cane sugar nonetheless. If you are concerned with sugar in your final brew, using a more processed sugar (rather than a less processed type like jaggery, honey, maple, succanat, etc) may actually be a better option. In my experience, the final brew is less sweet tasting (more quickly) when cane sugar is used. This may mean that the microbes have an easier time “digesting” the more processed sugar. As with tea, there are undoubtedly some SCOBYs that do just fine or prefer alternate sweetener types (Jun, for instance, is kombucha brewed with a SCOBY that likes honey as a food source, for instance). Experiment wildly. But maybe use a spare SCOBY.
Avoid artificial sweeteners and stevia which do not have any of the sugars necessary to sustain your microbes.
HOW TO CREATE THE RIGHT SELECTIVE ENVIRONMENT FOR KOMBUCHA
Temperature – Temperature is one of the most important aspects of just about all food fermentation. My favorite kombuchas are brewed at a warmer room temperature. Too cool, and fermentation might become sluggish or completely stop. Too warm and you end up with a rapid fermentation that can throw the balance of yeast and bacteria out of whack or even kill essential yeast or bacteria. Shoot for 70°F to 80°F. My booches tend to be happy clams at the higher end of that range but I’ve brewed as cool as 64°F and it was fine. It just takes longer to acidify at cooler temps. As with all things “culture,” individual SCOBYs may like warmer or cooler temperatures better and brew temperature can effect which microbes are dominant.
Air – Unlike other ferments you may have made some of the microbes in the SCOBY require air to do their fermentation jobs properly. You do want to cover your vessel to prevent dust and flying bugs from getting there, but covering with a clean cloth (coffee filter, paper towel, cloth napkin) and using a rubber band or string to secure it is your best bet to allow airflow.
FIZZ, SECONDARY FERMENTATION AND BOTTLING
- Secondary fermentation refers to the fermentation that occurs after the “finished” tea has been drained away from the SCOBY. During this time, sugars will continue to decrease and nutrients will continue to increase. This is also a great time during which to add flavors and fizz.
- Many store brands of kombucha add CO2 to make their kombucha fizzier than what you’ll naturally get at home, but there are ways to achieve a very fizzy brew without the aid of force carbonation. See a few of my favorite techniques below:
- Bottle It – See below for tips on this, but without bottling, you’ll be lucky to get serious effervescence.
- Sweetness – Make sure to bottle your brew when it’s sweeter than you would ultimately like it to be. Feeding the yeast while they’re sealed up in the bottle is the absolute most important component of final fizz. You may even add a pinch or two of sugar just before bottling.
- Secondary Fermentation – Since you’ll already be bottling, why not add some fun, fizz-friendly ingredients. Berries and juices work great and help with fizz, but get creative. Some of my favorite kombuchas have been decidedly wacky flavor combos. Herbs, spices, ginger, flavored teas, medicinals, vegetables—the sky is the limit. If I’m usuing savory ingredients, I often make a simple syrup from them to make sure some sugar is getting in there for added fizz.
Temperature – Warmer temperatures during primary fermentation will help with some fizziness.
- Space – Don’t overfill your bottle. With long-necked bottles, I leave the neck almost entirely empty. With something a bit shorter-necked, I leave 2 inches of space or more at the top of the vessel.
SECONDARY FERMENTATION OF KOMBUCHA
Secondary fermentation is your chance to add all the beverage flavors your heart desires. There are limitless ideas, from herbs and spices to vegetables and berries. Ginger is always an excellent option.
Here are a some of my favorites:
Bottles – A bottle that is intended to keep the fizz in (and, importantly, withstand the pressure that builds up during fermentation) is your best bet. Reuse store-bought komucha bottles, Grolsch bottles, growlers and old, plastic soda bottles. You can also find great containers at Fillmore Container and Midwest Homebrew Supply. Always remember that bottling carbonated beverages carries some risk of explosion, so be careful with how you store these bottles and be sure to regularly check them. Philly Homebrew stocks “Champagne-grade” flip cap bottles that are intended to withstand very high pressure. Ask them all about it. The bottles are not explicitly listed that way, but their helpful staff will direct and inform you.
Space – To bottle kombucha, use a fine mesh strainer and a funnel to keep any extra bits of SCOBY or yeast strands from going into the bottle. Add your juice or other flavorings. Don’t overfill your bottle. With long-necked bottles, I leave the neck almost entirely empty. With something a bit shorter-necked, I leave 2 inches of space or more at the top of the vessel AFTER any additions. NOTE: Letting those little slimy bits and bits of yeast into the bottle may help with carbonation, so if you’re really into fizz, try waiting to strain after secondary fermentation.
Seal the bottle, but keep very close tabs on it. The time that it will take to fully carbonate and infuse with the added flavors depends on multiple factors, including temperature, sugar in the added ingredients, the seal on the bottle and the age of the kombucha when bottled. Try bottling in a plastic bottle alongside your glass bottles. That way, you’ll feel the sides of the plastic bottle become rigid and you’ll know it’s time to put all of them in the fridge.
GENERAL KOMBUCHA INFORMATION
There are things chemicals in city water that are potentially bad for fermentation, but that doesn’t mean they aren’t there in bottled water, too. Chloramine is chlorine + ammonia and it is in most municipal water. You can’t boil it out and it can impact fermentation. I have used Philly water for virtually all of my ferments, much of it run through a charcoal water filter (Mavea) and some of it not. Over the course of several years and hundreds, if not thousands (I teach a lot of classes, y’all), of batches, I’ve never had one that failed to ferment, so I do not consider this a big problem.
Bottled water isn’t regulated nearly as stringently as tap water, so there is no benefit to purchasing it over tap water. You won’t know what’s in it.
I know this sounds weird, but don’t boil the water, just get it to almost boiling. Kombucha is an aerobic ferment (meaning it likes air), and it honestly does seem to taste better with water that has not had its O2 boiled out.
Yes, there is alcohol in kombucha. It is generally present in very small amounts (usually lower than the 0.5% that is legal to leave unlabeled). Even a beer strength kombucha would require a good amount of effort and planning (and possibly the addition of some commercial yeast after straining the liquid off of the SCOBY). Nonetheless, there are ways to lower alcohol. If you are extremely concerned about alcohol, stick to drinking it after primary fermentation (before bottling) and keep primary fermentation relatively brief. If you want to measure the alcohol, you’ll have to use a hydrometer, a device made for that express purpose.
Personally, I have absolutely no concerns about giving kombucha to children. There are many items on the grocery store shelf that contain small amounts of alcohol that are readily given to children and teetotalers, including yogurt and soda. The legal limit, without labeling, is 0.5% in the US (1% in most other countries I’ve found information on).
When your SCOBY is not in use store it in room temperature kombucha. Do not store it in the fridge. SCOBYs will keep almost indefinitely with monthly feedings of fresh, sweet tea. If you wait longer than that, it is unlikely to be an issue, but it’s best to keep them in liquid, even if its over-fermented liquid.
If there is mold on your SCOBY, it’s time to say goodbye. Unlike the molds that you might see in vegetable fermentation, you most likely do not want to brew kombucha with a moldy SCOBY. Err on the side of safety and toss it. I have never had a moldy SCOBY, despite some serious neglect. If you get mold, something really went wrong, so don’t play around.
When you have extra SCOBYs and nothing to do with them, try making a SCOBY hotel. Remove older (bottom) layers of SCOBY from your fermenting container, place them in a new vessel and cover with kombucha. Stick it in a cupboard and add new SCOBYs and kombucha any time you have extra. That way, if there’s an issue with your working SCOBY, or if all of your friends simultaneously discover the power of booch, you’ll have backups to plop into a fresh batch of sweet tea!
Even if you’re leaving them at room temperature for less than a day, be extremely vigilant. An exploding glass bottle is dangerous and even an exploding plastic bottle has potential for harm (not to mention extreme mess!). Also, open with care. Sealed bottles can become the ultimate squirt gun, which means wasting good booch and herculean clean up efforts!
Feel free to play around with alternative sweeteners during secondary fermentation (once the SCOBY has been removed). For primary fermentation, stick to cane sugar unless you’re using a spare SCOBY. Remember that the sugar isn’t for you, it’s for your microbes. The more “wholesome” the sugar is, the more your microbes will most likely need to work to break them down. More refined cane sugars are more readily consumed.
- Microbial Foods – Ben Wolfe breaks down the findings of a study of the microbial makeup of Kombucha SCOBYs, including debunking the newly (but somehow dearly) held belief that all kombucha is probiotic.
- Cultures for Health – A nice chart breakdown for different sizes and a variety of tips and tricks (I unfortunately cannot recommend their dried SCOBY, however. I have tried several and haven’t found them to live up to other SCOBYs in quality).
I have great admiration for the work done on Ben Wolfe’s website MicrobialFoods.org. I love his fermentation writing because it is based in rigorous science, but written to be clear for those of us who were bigger fans of Baudelaire than biology in college. I highly recommend bouncing around on there.
There are a lot of books on kombucha. There are not a lot of good books on kombucha. In ALL of your reading, I recommend extreme skepticism on health claims. Even some of the good books come saddled with some, eh hem, interesting health claims, so make sure to equip your personal experience meters and critical thinking while reading.
- The Big Book of Kombucha: Brewing, Flavoring, and Enjoying the Health Benefits of Fermented Tea by Hannah Krum
- True Brews: How to Craft Fermented Cider, Beer, Wine, Sake, Soda, Mead, Kefir, and Kombucha at Home by Emma Christensen
- The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from around the World
Some Other Stuff I’ve Written About Booth
You can find SCOBYs for purchase just about anywhere lately (from Etsy to Amazon), but remember that not all SCOBYs were not created equal. I’ve had more than one experience with a subpar SCOBY that made me think maybe kombucha wasn’t for me. I have not had the best tasting or fizziest booch from SCOBYs grown at home from commercial kombucha, nor from dehydrated SCOBYs.
Facebook Forums – Some forums, like Fermenter’s Kitchen and Wild Fermentation, have pages in the notes for those who are willing to ship SCOBYs. They generally do not allow people to charge for them, other than for the cost of shipping, so it’s a great place for those on a budget to find culture!
From a Friend – Culture and community go hand in hand, so for that reason, it’s always my number one choice to get SCOBYs from a buddy. Sometimes your friends may be overwhelmed with requests for SCOBYs, but they can spare plenty of freshly finished kombucha, you can grow your own, just by letting a jar of finished booch sit out for a week or so.
Too many SCOBYs! Cannot move.
Welcome to the club, my friend. SCOBYs readily reproduce themselves which initially seems like an awesome gift, but once you’ve given a SCOBY to all of your friends, neighbors and acquaintances, these blobs of fun can start to feel like your enemies. A few things to do with them:
- Try making a SCOBY version of the traditional nata de coco candy with them.
- Feed them to chickens. Word around town is that chicks love SCOBY flesh. (Unfortunately my dog does NOT)
- Add them to the compost pile. They make great, microbial contributions to the compost pile.
- Make a SCOBY Hotel (See SCOBY Care, above)
One thing not to do? Feel guilty about getting rid of them. One of the first years I brewed kombucha, I started to feel like I had to find a way to use each and every one of the SCOBYs that formed during booch fermentation. It quickly got overwhelming and gave me a feeling of associated dread about my kombucha. Over time, I learned to let go, and now boochie and I are both much happier.
How do I get these suckers apart?
Layers of SCOBY tend to merge together quite readily . Try pulling them apart with very clean hands. If that doesn’t work, cut off a chunk using kitchen shears. You can also cut with a knife, but (very clean!) scissors are easier.
There’s a hole in my SCOBY. Can I still use it!
Yup! You’ll even get to see a new layer of SCOBY form a cellulose cover the hole in future batches.
My SCOBY has mold on it
First, is it for sure mold? Fluffy? Green? Black? Pinkish? If it’s brown and stringy, it’s most likely just excess yeast which is of no concern. If it is mold, say bu-bye to your SCOBY and the kombucha liquid underneath it.
What are these brown stringy things?
They’re just excess yeast that forms during fermentation and nothing to worry about. I have found in my continuous brew, I almost never end up with these strings, so if they really freak you out, that’s an option!
Should I rinse my SCOBY?
Nope. No need. I’ve been running on babies from the same mama for over 3 years as of this writing, and she’s never been rinsed.
Should I refrigerate my SCOBY?
No, there is no benefit to refrigerating your SCOBY and the cooler temperatures could kill or weaken some of the less cold-tolerant yeast strains.
My kombucha is too sour.
Don’t brew it so long next time.
My kombucha is too sweet.
Give it more time to ferment. The longer it ferments, the more sour it will be. You can also experiment with lower sugar batches.
My kombucha isn’t very bubbly. How do I make it like the stuff from the store?
Fizz can be an issue. See above for the many tips I have on getting it to bubble town.
What’s the story with not letting the SCOBY touch metal?
If you’re not using restaurant grade stainless steel during fermentation, the acids in the kombucha could react with the metal and cause it to corrode. Corroded metal is probably not something you want to drink, so best to use only metal-free containers with metal-free fixtures or true stainless steel (stainless-plated does not cut it, so find out for sure). You don’t need to worry about this for straining or cutting SCOBYs. Momentary exposure isn’t going to hurt anything.
My SCOBY sunk to the bottom of my fermentation vessel. Should it be floating? Is it dead?
It is most likely fine. What sometimes happens is that a new SCOBY starts to form on the surface, and the CO2 produced during fermentation propels the older layers of SCOBY downward. If there hasn’t been a specific problem with your SCOBY, wait a couple days to see if it rises back up a bit. If it’s not laying on the bottom of the vessel, it’s fine, and even if it is, it is still probably fine. If a new SCOBY forms on the surface and the booch smells sour/vinegar-like, it’s fine. Feel free to toss a SCOBY that sits on the bottom, though, once you have a new one on the surface.