SCOBY Do’s and Don’ts: Your Kombucha Questions Answered

In 2014, I discovered that I absolutely love teaching fermentation (who knew?). My kombucha students have lots of questions during and after class so I thought I better write up an FAQ page. I’ll add more to this as more questions arise. If you have one that I haven’t addressed here, please ask away in the comments and I’ll do my best to answer. You can find my instructions for brewing kombucha here.

Which came first, the kombucha or the SCOBY?

You need a SCOBY to make kombucha but you need kombucha to make more SCOBYs. When I make scrap vinegar from apples peels and cores, usually SCOBYs spontaneously develop in my vinegar. I have used these to successfully brew kombucha. So I believe that some fruity or sweet liquid came first and then the SCOBY and then the kombucha. Then again, that liquid could have been sweetened tea, which, simply out of neglect, fermented into kombucha, which then formed a SCOBY. So, I don’t know. Sorry.

What’s the difference between a SCOBY, a mushroom and a mother?

These all refer to the same thing—the gelatinous blob that ferments your sweetened tea. I use them interchangeably, which confuses people. SCOBY stands for symbiotic culture of bacteria and yeast.

I can’t find a SCOBY. How can I make kombucha?

You may not have thought this question would lead to pondering the origins of life, but you have hit upon a bit of a chicken-and-egg problem. You need a SCOBY or kombucha to make kombucha. If you can’t find a SCOBY, buy some good-quality kombucha, pour a few inches into a wide-mouth jar, secure a cloth over the jar to keep out flies but promote air circulation and wait. In about a week, a thin film should form on top of the kombucha. You now have a small SCOBY.

Do I need a giant SCOBY to ferment my tea?

No. A small one will work. My first SCOBY fit into a tiny 1-ounce jar and soon proliferated and took over my kitchen.

My SCOBY died and I found a new one Craigslist. It has a larger (or smaller) circumference than my brewing jar. Will it work?

Yes. New layers will form that match the circumference of the jar. A cut-up SCOBY will also work.

Do I need fancy equipment to make kombucha?

No. You need a pot or kettle for boiling water, a wide-mouth vessel for brewing your kombucha, a measuring cup, a spoon and—if you want to go all out—a good funnel and some flip-top bottles.

I am a gluten-free kosher vegan with a peanut allergy. Can I drink this stuff?

Made with tea, sugar and water, kombucha contains no grains, dairy, animal products or CD jewel cases.

How many calories does kombucha contain?

The number of calories depends on the sugar content. If you let your kombucha brew for a long time, the sugar-loving SCOBY will consume all the sugar. But at that point, you’ll have vinegar, which has negligible calories but you may not want to drink it. GT brand kombucha claims to contain 30 calories per cup.

Can I brew with decaffeinated tea? How about herbal tea?

Decaffeinated tea will work. Avoid herbal or fragrant tea infused with oils, such as Earl Grey. Stick with tea from the camellia sinensis plant—black, green, oolong, white or puerh.

Sugar scares me.

It scares me too. But the sugar in your kombucha feeds the SCOBY, not you. If you let your kombucha brew for a couple of weeks (depending on your kitchen environment), the SCOBY will consume all the sugar, leaving you with vinegar. I prefer my kombucha with a little sweetness.

You have failed to convince me on the sugar. Can I use stevia instead?

No. You must use real sugar to brew your kombucha. I use organic evaporated cane sugar, sucanant, rapadura or coconut sugar. When starting out, I recommend students use something like one of these—basic, real sugar. If you want to experiment with honey, maple syrup, agave nectar or molasses, wait until you have some spare mothers. Don’t use your only mother. You may accidentally kill her.

Okay, fine. I’ll make some kombucha with sugar as you recommend. How do I know if it’s fermenting properly?

If your SCOBY floats to the top or it sinks to the bottom but a new thin layer forms on the top of your tea, it is fermenting properly. The tea will lighten in color over several days and will see some bubbling also. Finally, you can taste it. A developing vinegary flavor indicates all is well.

What is your sugar to kombucha ratio?

I use 8 parts tea to 1 part sugar. You may want to use a little less sugar or a little more.

Can I use tap water?

Yes. If your tap water smells highly chlorinated, fill a large vessel the day before you brew and leave it open to the air. The chlorine will dissipate. I have never had a problem with chlorine but it your water contains large amounts of it, it may kill the microbes in your kombucha. I boil ordinary tap water for my tea.

Does it matter if my SCOBY sinks or float sideways?

Generally, no. However, if your SCOBY sinks to the bottom and no new SCOBY forms on top of your tea, she has infertility problems and you must track down a new one.

What is that growing on top of my tea?

Congratulations! That thin, cloudy layer forming on top of your tea is a SCOBY baby. Think of a cute name.

I see brown strings and blobs under my SCOBY. Is this mold?

No. Mold needs air to form. It will develop on top of the tea or on top of the SCOBY and will look like, well, mold—black, white, green, furry. The brown blobs and strings are yeast. You want these in your kombucha.

I see black, white or green furry blobs on my SCOBY or the top of my tea. Is this mold?

Yes. Fortunately I have never had a mold problem but every time I peer into my tea, I brace myself for this horror. If you find mold, you must toss the entire batch of tea and your SCOBY and start over.

When do I know my kombucha is ready?

As with other fermented foods, your kombucha is ready when you like the taste. Generally, I taste mine on day five (although in the summer heat, it can ferment in as few as three days! I need a rest!). If you like the taste, you can either drink it all up or bottle it. Read more about bottling here.

OMG this tastes delicious! Can I drink the entire vat?

I do try to limit the amount of kombucha I drink. I don’t guzzle the stuff like a soda addict but rather drink about four ounces a day max—more if I teach a class. I’ll sample and choose my best flavors before class, taste during class, maybe polish off this little bottle over here after class…but I don’t have a problem!

I have tried to find guidelines on the recommended daily allowance of kombucha, but have found little information. Like other fermented foods, consume it in moderation.

OMG this tastes like pure vinegar. Should I throw it out?

No way! You need some kombucha to inoculate your next batch, so just use this, but only about half as much as usual. You can also cook, clean your house and rinse your hair with your vinegar. I no longer buy vinegar, which makes me just a bit less dependent on the grocery store. I either use my homemade scrap vinegar or my kombucha vinegar.

I want to flavor my kombucha. Do I do this during the initial fermentation?

No. I have read about people adding fruit to the initial fermentation but that is more of an advanced technique. Brew your tea as usual and then flavor it following these instructions.

How much flavoring do I add?

As a rule of thumb, add 10 to 20 percent fresh or frozen fruit to 90 to 80 percent kombucha. Read more about flavoring your kombucha here.

I am drunk.

All fermented foods contain trace amounts of alcohol. If I let my kombucha ferment for a long time (i.e., it tastes very vinegary), it contains more alcohol and I definitely feel its effects. But I am a complete lightweight with zero tolerance. You should see me after a glass of mead! Personally, I wouldn’t give my well-aged kombucha to anyone on the wagon.

I want this flavor to last forever.

Ah the permanence of impermanence. Although your strawberry flavored kombucha may taste perfect to you after completing the secondary fermentation, it will continue to slowly ferment in the refrigerator. Within only a couple of weeks, the honeymoon will have come to an end and your kombucha will taste more vinegary. But that doesn’t mean you should throw out the entire relationship…I mean bottle… When my kombucha tastes vinegary, I pour myself a glass with half older kombucha and half fresh kombucha from either a recently bottled batch or from my large jug brewing on the shelf.

Where do I find a SCOBY sitter while I vacation on the French Riviera with my Latin lover for two weeks?

Just leave your SCOBY in the tea. She will be fine. The kombucha will be quite vinegary but you can use it for cooking, cleaning, rinsing your hair…When you return, brew as usual. I have a SCOBY hotel for my spare SCOBYs. I leave them in a big jar of kombucha for up to 6 weeks. At that point, I transfer them to fresh tea. Bon voyage! (Does he have a brother?)

Will kombucha erase wrinkles, revert gray hair to its original color, cure cancer and improve my sex life?

No. But this probiotic, fermented food does confer health benefits. Read these 5 benefits of fermented food.

Just how much money will I save brewing my own kombucha?

This depends on the severity of your addiction. A student recently told me he drinks one 16-ounce bottle a day. That costs at least $25 a week for a ho-hum brand. I recently saw a bottle of kombucha at the store with a six-dollar price tag! It is tea! I use expensive, organic loose-leaf tea, organic sugar and organic farmer’s market fruit to flavor mine. At most, I spend 50 cents per bottle.

I am overrun with SCOBYs. Help!

Congratulations on your successful brewing adventures. You can try a few things to reduce your SCOBY population. Post an ad on Craigslist. People are always looking for SCOBYs and you can even charge money for them. I have never made kombucha candy, but here is a recipe for it. On Instagram, I once saw a video of a guy playing in a jazz band on the drum he made of spare SCOBYs. Coolest thing I ever saw in my life.

Spreading SCOBY love around the world

My SCOBY lives all over the world. If you ever travel to the Bay Area, let me know and you can have a piece of Ethedreda to take home.