A glass of kombucha made from high mountain Taiwanese oolong tea (courtesy of my aunt's tea shop). This particular batch had a fragrant honey flavor, light fizz, and champagne-like color.

Four batches of kombucha in, I'm ready to give a full report on kombucha brewing. Please let me know if anything is unclear so I can edit my instructions. I plan to send this to people who ask me how to make kombucha in the future, so I want it to be very precise.
Reminder: you can click on any of the photos to enlarge them and get a good look at what's going on.
First, a quick lesson: kombucha (translation: kombu tea) is usually considered a new age Japanese health product, but it's been used all over Asia for hundreds of years. In a nutshell, it's fermented tea. Some people call it mushroom juice, others tea wine. You'll understand why these names were chosen if you decide to keep reading.
To make kombucha, one needs the following:
- kombucha culture (parent culture)
- 1 cup kombucha
- 1 gallon clean water
- pot big enough to boil a gallon of water
- enough tea for 8 strong cups of tea
- 1 cup granulated sugar (brown sugar works too)
- clean glass container able to hold a gallon of water, no lid necessary
- paper towel or clean hand towel
- rubber band
- Enough glass bottles with lids to hold all the liquid. The lids need to be plastic.
If you're brewing for one and/or only have smaller cooking vessels, cut the amounts in half (half a gallon of water, half a cup of sugar, half gallon sized glass jar, etc.). I've tried this and it still works well. In fact, the first time it worked so well I decided a little extra sugar and old kombucha in the new brew was a good idea. Extra food for what might be a slightly week culture.
I got my kombucha culture from a friend. Kombucha owners are happy to share, both because it's really fun to pass on knowledge and because if you make kombucha regularly you create more cultures than you can possibly use. The culture, which is a symbiotic living mass of yeast and bacteria, is about a third of an inch thick and rubbery. To me, it feels sort of like a large raw squid. The color is slightly off white like a very clean, thick layer of lard. However, the culture will darken depending on what kind of tea it's soaked in and darkens with age. Kombucha culture is also sold on line, and I've heard some health food stores sell frozen cultures. The one in this picture is floating in some fairly sour kombucha, which smelled almost like pure vinegar.
Before you begin, clean everything including your hands and forearms with hot soapy water. Cleanliness really counts for this kitchen project.
To start, boil a gallon of water and brew your tea in it until the tea is nice and strong. Alternatively, you can boil a few cups of water, make extra strong tea in it, add the cup of sugar, make sure the sugar melts completely, and dilute the liquid with clean bottled water. Since the water needs to be sterile, however, you don't want to brew a small amount and then add tap water. And since I don't spend money on bottled water, I find it easier to just boil a whole gallon of water and let it cool down to body temperature before I start.
When the tea is warm, strain out the tea. Put in the kombucha culture and a cup of old kombucha. I haven't measured the temperature exactly, but the tea needs to be cool enough to comfortably put your hand in for at least twenty seconds. It's important not to kill the culture by burning it, but the culture won't like cold tea either. Anything between room temperature (70) and body temperature (98) should be fine.
At this point, your culture might sink, float, or stand up vertically like the one in this photo. Don't worry about it. Cover with a clean towel and wrap with a rubber band. This will keep stuff from falling in. Keep the kombucha in a cool dark place with plenty of air. I keep mine in an ajar cabinet, but any dark corner is fine. You want to avoid places with a lot of fumes (garage) or too much grease (open area of kitchen).
Leave the brew alone for at least five days. Since my apartment is relatively cool, every batch of kombucha I've made has taken at least seven days. It will be faster in hot weather and slower in cold weather. I've heard it can take between one and three weeks, so that's your window. Things that can slow down kombucha maturation include but are not limited to:
- cold weather
- a very young parent culture
- a very old parent culture
- a weakly formed parent culture (thin, uneven)
- oil in your tea (such as bergamot in Earl Grey)
- oil on any of your cooking utensils
- fruit in your tea (again, with the oil)
- you used brown sugar
- you didn't use real tea (chamomile, mint, apple, etc.)--this won't work at all
- you didn't add enough old kombucha
- your old kombucha was a little weak
As your brew ages, the culture will create a "baby" culture on the surface of the tea. The culture, which is alive, begins to process the sugar and caffeine in the tea. That's why you need to use real sugar and real tea. No Splenda, no decaf. Don't worry, your final product will be both sugar and caffeine free. The sugar and caffeine is there for the culture to eat. Not you. What you will be ingesting is the "waste product" of the culture. These waste products include a myriad of acids, B vitamins, vitamin C, various forms of yeast, and some bacteria. Just as the flavors of wild yeast caught for bread or beer will differ depending on environment, your kombucha's flavor will differ depending on what's floating around in your home.
The appearance of the "baby" is an indicator of the health of your "parent." The first few days it will seem like nothing is happening. Then, a white ring will begin to form around the edges of the tea, clinging to the glass jar. Then, usually overnight, a thin layer will develop on the surface of the tea, like in this photo. This layer will thicken and become quite solid by the one week mark. Weak baby formation is caused by one of the causes I mentioned above.
I've also noticed that if you haven't strained your tea through a fine mesh, sometimes little tea bits will float to the surface and get caught in the baby. Sometimes this makes ugly bubbles, or dark blotches on the baby. It's really ugly and undesirable, so strain your tea well. Even better, use loose leaf tea. Tea bags are made with broken up, sometimes powdery tea that is too low quality to sell as loose leaf. If you use loose leaf tea the large leaves will stay intact during brewing and there won't be residue to get caught in the baby.
Kombucha is one funky looking creature. As it brews, different things start going on. My first brew started bubbling furiously after about five days. I could see bubbles rising from the baby culture up to the surface. I also accidentally knocked the jar, displacing the layer that had formed on the surface. What happened was that a new layer formed, so my new baby was two thin cultures instead of one thick one. Lesson: don't jostle the kombucha! Another time, I noticed cloudy webs floating in the tea, linking the old culture to the baby culture. Kind of like a Creation of Adam thing going on in my cabinet. You can see shadowy strands in this photo. The color of the tea will also change. It might get a little cloudy from the yeast, and it will lighten from the acid in the kombucha.
After day 5, use a spoon or straw to taste a little of your kombucha. It should no longer be sweet. Instead, it should smell and taste a lot like apple cider vinegar. You want there to be a faint tang, and if you're lucky the kombucha will be fizzy as well. If it's pretty tangy, it's time to decant. Otherwise, leave it and taste it every day until it's what you want.
It's hard to know what's right for you the first time around. Just keep in mind that the kombucha should not taste sweet. If it's still sugary, the brew's not ready. And it will mellow out after decanting, so remember that if it tastes a little tangy it will lose some of that quality before you drink it.
To decant, you need some clean glass bottles with plastic lids. I use old alcohol and juice bottles. Glass is best, plastic is fine. Metal will kill kombucha. Before you start, set aside the old culture and baby culture in a few cups of the kombucha. Keep the tupperware in a cool dark place, slightly ajar so the cultures can breath. I was going to start a new brew right away so I put the baby culture and a cup of tea back in the glass container. This bottle looks a little darker than it actually is because of the dark wood table, but it's kombucha made from oolong so it's actually lighter than apple juice.
Using the rest of the kombucha, fill the bottles to the very top, leaving no room for air. This will help the kombucha develop fizziness, and keep the bottle from exploding from the built up pressure. Leave the bottles in a cool dark place for five days, then transfer to your refridgerator. I've been pretty good about finishing my kombucha, so I'm not sure how long it lasts if you don't open it. Some people say a few months in the fridge. I notice that opened bottles start tasting pretty sour after two weeks, so I wouldn't keep opened bottles around for too long.
You can start a new brew right away with one of the cultures. It's up to you whether you want to use the new baby (which will now become a parent) or the old parent. Here is a picture of a brand new baby culture with a cup of just-made tea. You can see that some fizz formed when I poured the tea back into the container. I don't know if it's luck or what, but I've always had very fizzy results. This combination of tea and culture is what you need to start a new brew. Just add a gallon of lukewarm strong tea that has a cup of sugar melted into it.
Parent cultures are good for about a dozen brews. The performance of a parent takes on the shape of a bell curve. The first few babies it makes will be a little on the thin side, then it will make a few great babies before it starts getting old and is ready to be buried in the back yard or thrown in the garbage. If you find yourself with two very thin parents, use them both in the same container to make your next brew. Hopefully you'll end up with one great baby. Like I keep saying, everything's trial and error with kombucha, so go with your gut. Ideally I want to keep two or three healthy cultures going at all times in case I kill one.
What tea is best? You can use any black, green, or oolong tea to make kombucha. As you can tell from my photos, I've used tea that's almost black as well as tea that's a pale honey color. The important thing is to use caffeinated tea and tea without a lot of oil or fruit in it. I tried using passionfruit black tea once. It eventually worked, but the fruit oils in the tea made the baby very thin and uneven. The kombucha itself was mild and not very fizzy. If I use passionfruit tea again I would cut the amount in half and use a good black tea as well.
I've had the best luck with high quality Taiwanese high mountain oolong (It's the one in the glass in the first photo). Great flavor, beautiful pale color, and an extremely thick, white baby (it's the perfectly round one in photos above). The best cheaper alternative has been Stassen jasmine green tea bags, available at most Chinese markets.
A closer look at an especially well-formed kombucha baby. Because it was made in a jar of oolong tea, the culture wasn't darkened by dark tea. It's the color of lard, and smooth and shiny all over. I was really proud of this one.
I've heard that people flavor their tea when they bottle it. Some people put in a few pieces of dried fruit or fresh ginger. I'll report back if I do a ginger infused kombucha. I'm hoping it will be like homemade ginger ale. So far, I've noticed that extremely dark black tea makes a hoppy brew sort of like beer. A lighter tea makes a tea that tastes more like an unsweetened wine cooler. I notice that the bubbles in kombucha are smaller than bubbles in soda. Best of all, kombucha will create a little carbon dioxide even after being opened, so it stays bubbly for over a week instead of going flat like soda.