Ultimate Guide to Kombucha

Guide to Kombucha

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About the Author

Kriben Govender

Kriben Govender, is a Food Scientist, Registered Nutritionist and Founder of Nourishme Organics, a company specialising in Gut Health and Mitochondrial health-focused products and Allele Microbiome – a provider of cutting edge Metagenomic Stool Testing and Deuterium Testing.

 

 

• What Is Kombucha?
• How to Make Kombucha
• The Science of Kombucha
• 4 Health Benefits of Kombucha
• Kombucha Safety, Caffeine, and Alcohol Content
• Final Thoughts

 

 

Kombucha is a delicious, tart probiotic beverage made from tea.

Researchers are only beginning to understand the living microorganisms within kombucha and their potential health benefits.

One thing is certain, though: if you’re buying sugary, commercial kombucha products, you’re not only wasting money, but also missing out on an authentic kombucha experience.

Fortunately, this guide explains everything you need to know about making kombucha, as well as useful scientific facts to help you become educated on the topic.

The estimated reading time is 25 minutes, but you can also browse these topics of interest:

• How to make your own kombucha using a starter culture or SCOBY mother (read more)
• How to make kombucha at home without a starter, using ingredients available at most grocery stores (read more)
• Troubleshooting kombucha and caring for the mother (read more)
• Safety, side effects, caffeine content, and alcohol content of kombucha (read more)
• Recent scientific findings on kombucha (read more)
• What peer-reviewed research says about kombucha’s health effects, and how its benefits compare to other probiotic foods (read more)

Otherwise, keep reading for an overview of kombucha: its appearance, taste, origin, and nutrition facts. 

What is Kombucha?

Kombucha is a probiotic beverage made by fermenting sweetened tea in a vessel with a large symbiotic colony of bacteria and yeast (SCOBY), also called a “mother” (and sometimes mistakenly called a “mushroom”).

Most kombucha ranges in color from light yellow to a deeper golden-brown or reddish brown, depending on the type of tea added to the fermentation vessel.

The flavor of kombucha is best described as tangy, tart, and sometimes slightly fruity or vinegary. The sweetness level can vary depending on the chosen sweetener as well as the length of fermentation (longer fermentation times reduce sugar content and increase tanginess).

When fermented in a sealed vessel, the liquid is also fizzy or effervescent due to natural carbonation.

The biggest noticeable difference between kombucha and other fermented beverages (such as milk kefir and water kefir) is the presence of the distinctive SCOBY mother during fermentation, which takes the form of a solid, floating mat. And unlike more fragile vinegar mothers, kombucha mothers are robust and rubbery.

Although SCOBY mothers are potentially edible (and some people even cut and dry them as a type of snack or candy), consuming them is not part of drinking kombucha–instead, the mother is preserved and used for producing future batches.

The Nourishme Organics Ultimate Kombucha Brewing Kit provides the ultimate home-brewed kombucha experience. There’s no simpler, safer, or easier way to make your own kombucha at home–it contains everything you need to get started, including vessels, a SCOBY mother, tea, and even sugar.

Learn more about the Ultimate Kombucha Brewing Kit, the best system for continuous kombucha brewing and second fermentation.

The extremely unusual appearance of SCOBY mothers is due to the tendency of kombucha cultures to form a thick, dense layer of cellulose [1] .

Unlike other probiotic culture colonies (such as kefir grains), the SCOBY sits atop the kombucha and gradually assumes the shape of the fermentation vessel, so it’s most often a large circle up to 1 cm thick.

Over time and with repeated fermentation cycles, large SCOBY “mothers” will grow more layers and produce smaller SCOBYs, sometimes called “daughters,” that can be separated and used to ferment more kombucha (or share with others).

The first SCOBY may have been created serendipitously by an insect or other organism transferring aceticacid-producing bacteria into a solution that already contained live yeast. While there are numerous legends, no one knows the exact origin with certainty.

It’s possible that all kombucha cultures today originated with one SCOBY that has since been shared and passed from generation to generation and culture to culture.

Researchers think that kombucha first originated in northeast China, then spread to Europe by way of Russia, but its exact origins and the length of time it’s been in use are unknown, at least in Western historical accounts [2] .

If you’re interested in exploring different strains of kombucha, try Jun Kombucha. Believed to originate in the colder climates of Tibet, it’s known as the Champagne of Kombucha. The raw, organic Jun Kombucha kit is fun and easy and can provide a lifetime supply of kombucha.

Shop Jun Kombucha now. 

Kombucha Nutrition Facts

The basic nutrition facts of kombucha vary depending on the type and amount of sweetener used, as well as the length of fermentation.

Longer fermentation times result in lower sugar levels as microorganisms consume sugar and convert it into lactic acid, acetic acid, and other delicious, healthy metabolites [3] .

In many countries, commercial kombucha is labeled as having carbohydrates or sugar, even though this may not be accurate.

For example, in the United States, nutrition labeling reflects the ingredients that were combined during initial production, but not the actual sugar content of the final product following fermentation.

As you can see from the below kombucha nutrition facts obtained from the USDA, that means commercial kombucha labels will indicate the product contains carbs and sugar.

Per 237 ml (8 oz.) [4] :

• 45.6 kcal
• 0 g protein
• 0 g fat
• 11 g carbohydrates
• 7.01 g sugar
• 0 mg sodium

However, it’s better to think of those nutrition facts as a maximum possible level of carbs and sugar.

For high-quality kombucha products that undergo real fermentation, the actual amounts should be 50% or lower of what’s listed on the label.

Unfortunately, many commercial producers of inauthentic kombucha add sugar or other carb sources (like juice) after fermentation and then refrigerate their products. Therefore, high levels of carbs and sugar on labels are likely to be accurate.

If you follow the ketogenic diet or another low-carb diet, or would simply prefer to avoid sugar, the simplest way to determine whether a batch of kombucha is suitable or not is to taste it. 7

Kombucha in which the sugar has not been converted through fermentation will taste much sweeter. The more tartness and sour notes, and the less sweetness you detect, the lower the sugar content.

If you make your own kombucha, as you’ll learn how to do in the next section, you can rest assured that kombucha that ferments for 10-14 days (and sometimes less, depending on ambient temperature) and tastes very tart and dry contains almost no sugar.

How To Make Kombucha

Kombucha is easy and fun to make. And aside from the mother or a starter culture, all of the ingredients you need are easy to find and very inexpensive household items.

You can experiment with many different details, but most formulas include a similar set of principles:

1. Make tea (Camellia sinensis), then remove the leaves or bags
2. Sweeten the hot tea with sugar , then allow it to cool
3. Add a kombucha culture
4. Ferment in a warm location, preferably above 21 degrees Celsius (70 degrees Fahrenheit), for 7-14 days (cooler or warmer environments can change fermentation times) 

The Simplest Kombucha Recipe

If you’ve never made kombucha before and don’t know anyone who makes kombucha, the simplest and easiest way is to use a kombucha starter.

Starters are liquids or powders with dormant kombucha cultures that are easily activated by adding tea and sugar.

Here’s how to use them:

1. Boil or heat non-chlorinated water (preferably spring water or well water).
2. Add and steep black tea leaves or bags for about 5 minutes (recommended: 4 teaspoons or 4-6 grams of tea leaves per liter of final volume, or 2-4 tea bags per liter of final volume).9
3. Remove tea bags or strain into a large vessel (preferably glass or ceramic) to remove tea leaves, then add sugar (recommended: a 5% solution, 50 grams or 1/4 cup of organic white sugar per liter of final volume) and mix.
4. Allow the mixture to cool to room temperature.
5. Add the proper amount of kombucha starter culture (for example, 100 ml starter per liter of tea) and cover with a breathable cloth or paper towel (secure on top with an elastic band or twine).
6. Allow the mixture to ferment in a warm location.
7. Once a thin SCOBY mother begins to form on top, taste the kombucha daily.
8. When the taste matches your preferences for tartness and sweetness, the kombucha is ready to drink or store in your refrigerator.
9. Remove the mother and up to a cup (250 ml) of mature kombucha to start another batch, now or in the future.

Unlike the method in the next section, you’ll want to delay drinking or storing the kombucha starter batch until the initial SCOBY mother forms.

If your mixture remains active (bubbling) without forming a mother on top, try adding more sugar in the form of simple syrup (combine equal parts sugar and hot or boiling water, then allow to cool first) every few days until a mother forms.

Once a SCOBY mother forms, you can drink or store the liquid, then use the next recipe listed below to make kombucha going forward. 

Kombucha from SCOBY Mother Recipe

If you’ve never made kombucha before and don’t know anyone who makes kombucha, the simplest and easiest way is to use a kombucha starter.

Starters are liquids or powders with dormant kombucha cultures that are easily activated by adding tea and sugar.

Here’s how to use them:

1. Boil or heat non-chlorinated water (preferably spring water or well water).
2. Add and steep black tea leaves or bags for about 5 minutes (recommended: 4 teaspoons or 4-6 grams of tea leaves per liter of final volume, or 2-4 tea bags per liter of final volume).10
3. Remove tea bags or strain into a large vessel (preferably glass) to remove tea leaves, then add sugar or another sweetener (try starting with a 6.25% solution: 62.5 grams of sweetener per liter of final volume, but adjust upward if needed based on preference and fermentation activity) and mix.
4. Add water to cool and achieve final volume, or otherwise allow the mixture to cool to room temperature.
5. Add the kombucha mother and up to a cup (250 ml) of mature kombucha liquid, then cover with a breathable cloth or paper towel (secure on top with an elastic band or twine).
6. Allow the mixture to ferment in a warm location for approximately 7-14 days.
7. Taste the kombucha regularly. When the taste matches your preferences for tartness and sweetness, the kombucha is ready to drink or store in your refrigerator.
8. Remove the mother and up to a cup (250 ml) of mature kombucha to start another batch, now or in the future.

Also, as your healthy SCOBY colony grows over time, you have two choices:

● Peel off new layers and give them to a friend, dehydrate (on unbleached parchment paper somewhere clean and warm, until dry) and store, or do something else (like add them to your compost pile)

● Increase the size of your fermentation vessel and produce more kombucha!

On the other hand, if you don’t have a SCOBY yet and don’t have access to a starter culture, there’s still a way to make your own kombucha, which we’ll cover in the next section. 

Kombucha from Commercial Kombucha Recipe

If for whatever reason you can’t order kombucha starter culture and don’t have a friend with a SCOBY mother to share, you can still make your own kombucha by using commercial kombucha as a starter.

This method is more difficult than the others, and may take multiple attempts, but it’s well worth it if you don’t have another option.

The basic idea is to use the highest-quality store-bought kombucha you can find as a starter to create your own SCOBY mother.

In this case, high quality means authentically fermented, raw (non-heated, non-pasteurized), tart- and sourtasting kombucha, free of preservatives and with relatively low sugar content (both on the nutrition label and in terms of tasting only faintly sweet).

Ideally, select an organic kombucha brand that’s unflavored or only contains natural ingredients, like ginger. The more sediment and fiber-like strands you can see settled or floating in the bottle, the better.

Unlike other methods, the only goal of your first batch is to produce a mother to make more kombucha. It’s unlikely that you’ll immediately get drinkable kombucha in the initial process, and it may require some adjusting to even create a mother.

The process starts off similarly to other methods:

1. Boil or heat 1/2 to 1 liter of non-chlorinated water (preferably spring water or well water).
2. Add and steep 4 teaspoons or 4-6 grams of black tea leaves, or 4-6 black tea bags, for about 5 minutes.
3. Remove bags or strain into a large vessel (preferably glass) to remove tea leaves, then add 62.5 grams of organic white sugar and mix well.
4. Add 1/2 liter of spring or well water to cool and bring to 1 liter total volume, or otherwise allow the 1 liter mixture to cool to room temperature.
5. Add 250-500 ml of high-quality store-bought kombucha and cover with a breathable cloth or paper towel (secure on top with an elastic band or twine).
6. Allow the mixture to ferment in a warm location and monitor daily for activity.

In the best case scenario, you’ll notice a SCOBY mother forming on top within 7-14 days. If that occurs, you can use the Kombucha from SCOBY Mother recipe above, and even drink the kombucha that was produced.

However, it’s also possible that you’ll run into one or more problems. If that happens, use the steps below.

Problem: Lack of activity (no bubbling or signs of fermentation after 2-3 days, or bubbling stops prematurely without a SCOBY mother forming on top).

Solution: Add an additional 250 ml of store-bought kombucha, 160 ml of simple syrup (made by mixing 100 g organic white sugar into 100 g very hot water), and 100 ml of black tea concentrate made by steeping 4-6 grams of black tea for 5 minutes. Allow all ingredients to cool before adding. Also move the entire mixture to a warmer location if possible.

After adding more active kombucha, sugar, and tea, the mixture should begin actively fermenting within 1-3 days.

If it doesn’t become active and didn’t activate from the start, it’s possible the brand of kombucha you chose is inactive (dead or pasteurized). You can either add a different brand of store-bought kombucha to your current mixture, or start the entire process over with a different brand.

Problem: Mixture is active, but no mother is forming after 7-14 days, or mother is very thin and mixture no longer appears active.

Solution: Add 160 ml of simple syrup (made by mixing 100 g organic white sugar into 100 g very hot water, then allowing to cool) every 3-5 days to maintain or restart activity.

If the mixture 12 still remains active but still doesn’t form a SCOBY mother, try adding 100 ml of black tea concentrate made by steeping 4-6 grams of black tea in 100 ml water for 5 minutes each time you add simple syrup. Allow tea concentrate to cool first.

If your mixture stays active long enough, a mother will eventually form on top, but added sugar may be required to sustain activity in the meantime. Some research suggests that adding more black tea can also help form a robust mother by increasing cellulose production, too [1] .

Problem: Mixture is moldy, very cloudy, or smells “off.”

Solution: Unfortunately, something went wrong and there’s no way to fix this batch. Start over, possibly with a different brand of store-bought kombucha.

Mold or “off” smells are clear signs that your batch isn’t going to turn out how you had hoped. A cloudy mixture can be all right (it may merely indicate high yeast levels), but is also a warning sign under certain conditions. 

Kombucha “Soda” (Secondary Fermentation) Recipe

Kombucha “soda” is the result of a secondary fermentation in a sealed vessel.

Along with carbonating kombucha liquid and making it fizzy, the secondary fermentation is also an opportune time to add juices or other flavoring ingredients, such as herbal extracts or infusions.

Safety note: Secondary fermentation involves high pressures, and is potentially dangerous when using sealed glass vessels. For safety reasons, consider using high quality BPA-free plastic bottles instead (which can’t shatter and also allow you to monitor pressure levels more easily). Alternatively you can use these gas rated glass .

The simplest way to make kombucha soda is to take “young” kombucha that’s only fermented for about 3-5 days and is still fairly sweet, then add it to a sealed vessel in a relatively warm area for approximately 24-48 hours. As the fermentation process continues, the gases will naturally carbonate the kombucha since they have nowhere to escape.

But if you want to use mature kombucha, which contains less sugar due to being further along in the fermentation process, you’ll need to add an additional source of sugar. To make kombucha soda from mature kombucha, add 2 cups (500 ml) of any fruit or vegetable juice (preferably freshly made), 25 grams of organic white sugar, another sweetener, or 40 ml of simple syrup per 1.5 liters of kombucha.

Troubleshooting and Caring for Your SCOBY

Keep in mind that SCOBY mothers are colonies of living microorganisms. Like all living organisms, SCOBYs require the proper conditions to remain healthy.

If your SCOBY is producing delicious kombucha and growing, there’s nothing to worry about.

But if your batches are slowing down, the fermentation seems less active than before, or the kombucha flavor is changing in a way you don’t enjoy, there are several potential causes:

• Your SCOBY mother may have grown too large for the current vessel, in which case you can divide it or use a larger vessel (scaling the recipe up accordingly).
• You may not be using enough sugar, so double-check your recipe (and remember that the sugar primarily converts into lactic acid and acetic acids during fermentation, so it’s not unhealthy to add sugar if needed).
• Particularly in warm environments, you may be allowing fermentation to go on for too long, and essentially starving your SCOBY. Try shortening the duration or moving to a cooler location.
• If you recently changed ingredients (such as a different sweetener or tea), you may have shocked your SCOBY, so try going back to the original formula and changing over gradually instead. Also, not every SCOBY will thrive with every possible combination of ingredients.
• If you’ve stored the SCOBY in the fridge for too long, or otherwise neglected it, you may need to nurse it back to health by replacing the mixture of tea and sugar (or adding tea and sugar) more often than usual, probably without drinking the liquid until the SCOBY shows signs of recovery (such as renewed activity).

Never use calorie-free or non-nutritive sweeteners, not even natural ones like stevia, during kombucha production. While you could add those types of ingredients just prior to drinking if you wanted more sweetness without sugar, they’re generally bad for SCOBY health (and don’t offer any benefit because they don’t provide energy for the microorganisms).

Also, along with only gradually introducing new ingredients so as to avoid shocking your scoby, another wise practice before adding new ingredients is to separate a portion of the mother with 100 ml of mature kombucha liquid and either preserve them separately (by continuing to make kombucha as before, or storing at room temperature like vinegar), so that if something goes wrong, you’ll have a “backup” SCOBY that isn’t affected.

In the upcoming sections, you’ll discover lots of fun variations on the basic kombucha recipe. 

The Best Kombucha “Sweeteners” and How Much to Use

Most SCOBY mothers are accustomed to white sugar, so organic white sugar is an excellent choice to begin with.

Bearing in mind the fact that most of the sugar in kombucha is no longer sugar by the time you drink it, there are very few drawbacks to staying with white sugar.

But there are potential benefits to other sweeteners, especially in terms of exploring flavor changes. Consider any of the options from this list if you want something different:

• Maple sugar or maple syrup
• Coconut sugar
• Brown sugar
• Raw sugar, turbinado sugar, evaporated cane juice, or other alternative forms of sugar
• Honey
• Molasses

Most bacteria and yeast require the simple sugar glucose for fuel, and the glucose content of a sweetener can change the rate of fermentation and the active kombucha species [3] .

The sweeteners above are listed from highest glucose content (maple syrup) to lowest glucose content (honey and molasses) [5] [6] [7] .

Sucrose (table sugar and other varieties of cane sugar) contains 50% glucose and 50% fructose bound together, which microorganisms must break apart to use for energy [3] . (Some types of bacteria or yeast within kombucha can also convert other sugars into glucose.)

High-glucose sweeteners tend to result in faster fermentation, while lower-glucose sweeteners are more likely to shock SCOBYs, slow fermentation, and dramatically change the flavor profile of kombucha.

 

The Best Teas for Making Kombucha

Black tea and green tea are the most common preparations of Camellia sinensis used to make kombucha, but you can also use other varieties, including:

• White tea
• Oolong tea
• Sheng or “raw” fermented pu’erh tea
• Shou or “ripe” fermented pu’erh tea

According to a study performed in 2020, the type of tea used can significantly affect the qualities of kombucha [8] .

Pu’erh and green teas appear to result in the highest levels of polyphenols and other antioxidants, but other teas are also worth a try, especially if you’re interested to explore new variations of kombucha [8] . 

Tea Alternatives for Making Kombucha

Other than “true teas” made from Camellia sinensis, people also use herbal teas or other ingredients in place of tea to make kombucha.

Examples include:

● Hibiscus tea (Agua de Jamaica)

● Coffee

● Lemon balm (Melissa officianalis) herbal tea [2]

● Rooibos herbal tea [9]

Studies have found that kombucha made from lemon balm and rooibos has different antioxidant content and other properties that may offer unique advantages compared to traditional kombucha [2] [9] .

Along with changing sweeteners, experimenting with tea alternatives is also likely to shock your SCOBY mother, so be sure to transition gradually or divide the mother up beforehand to keep a “backup” store of kombucha in case your experiment goes wrong.

If you want to get wildly experimental, a recent study also showed that kombucha cultures may even be used to create fermented milk drinks [10] .

The researchers added active SCOBY (10%) and mature kombucha (8%) to milk for 12-24 hours at 42 degrees Celsius (107 degrees Fahrenheit) to create an inoculation culture, then added that culture to milk in a concentration of 2.5-5% at the same temperature, until it coagulated into a yogurt-like product after 7-8 hours.

There’s no guarantee that dairy kombucha will be better than traditional kombucha, but it’s certainly worth a try if you’ve got an extra mother and don’t want to double your kombucha production yet again.

 

Ideas for Flavoring and Spicing Up Your Kombucha

There are two different ways to add spices, herbs, or other flavors to your kombucha:

• During the initial fermentation process, or
• as you make kombucha “soda” during secondary fermentation.

The possibilities for extra ingredients are as limitless as your imagination, but here are some ideas to get you started:

• Lemon or lime juice
• Other fresh-squeezed fruit or vegetable juices
• Ginger, fresh or powdered
• Turmeric, fresh or powdered
• Mint, lavender, thyme, rosemary, cinnamon, eucalyptus, nutmeg, or other herbs and spices (fresh or powdered)
• Cayenne peppers, fresh or powdered
• Fresh habanero or jalapeno peppers, diced

Adding extra ingredients for flavoring or other health benefits during the initial fermentation process (with the SCOBY mother) is more likely to result in interesting flavor transformations, and may also create new fermentation byproducts with added health benefits.

However, it’s also more likely to shock the SCOBY mother or cause other unpredictable changes. As in the other recipe sections, the advice of adding ingredients gradually or creating “backup” mothers in separate batches applies.

Mixing in juices, spices, herbs, or other ingredients during a secondary fermentation process is an easy way to achieve more predictable flavors with zero risk of affecting the health of your SCOBY mother.

You can also mix in higher quantities of unusual ingredients without risking compromising the quality of the kombucha or affecting future batches.

If you’re feeling extra creative, you can even experiment with adding some extra ingredients during the initial fermentation, and others during secondary fermentation!

The Science of Kombucha

With so many potential variations on the basic kombucha recipe, researchers could easily conduct hundreds of studies on different starter ingredients and sweeteners, SCOBY composition, and their effects on the resulting kombucha liquid.

Although scientific interest in kombucha has grown five- to tenfold in the past decade as interest in probiotics and the microbiome have also increased, there were still only 34 studies published involving kombucha in 2020, and most of them focused on kombucha’s composition and its basic properties [11] .

In other words, there’s a lot left to learn about kombucha, and the science is relatively new. Below you’ll find summaries of recent scientific findings on kombucha, followed by possible health benefits of kombucha according to peer-reviewed research.

 

Kombucha Contains Other Microorganisms, Not Just Bacteria and Yeast

The technical name for the colony of microorganisms in kombucha, “SCOBY,” refers to the presence of symbiotic species of bacteria and yeast.

While this name is partially accurate, kombucha contains more than those two types of microorganisms.

In fact, another common name for kombucha SCOBYs, “mushroom,” also contains a kernel of truth. While kombucha doesn’t actually contain mushrooms, it can contain non-yeast fungal species [12] .

Recent research also shows that fermented foods are rich in viruses [3] .

But don’t worry–these viruses aren’t harmful, and may well be good for your health.

In particular, viruses known as bacteriophages (literally “bacteria eaters”) play essential roles in bacterial succession and stabilization in many probiotic foods, likely including kombucha [3] .

They may also have gut health benefits.

Known microbial species commonly found in kombucha include [13] [14] [15] [16] [17] [18] [19] :

• Komagataeibacter spp. (bacteria)
• Gluconacetobacter spp. (bacteria)
• Gluconobacter spp. (bacteria)
• Rhodospirillales cluster (Acetobacter xylinum bacteria and Gluconobacter sp.)
• Acetobacter pasteurianus (bacteria)
• Acetobacter xylinum (bacteria)
• Gluconobacter oxydans (bacteria)
• Brettanomyces spp. (yeast)
• Schizosaccharomyces spp. (yeast)
• Saccharomyces ludwigii (yeast)
• Pichia spp. (yeast)
• Torulopsis sp. (yeast)
• Zygosaccharomyces bailii (yeast)
• Zygosaccharomyces kombuchaensis (yeast)
• Ascomycetes spp. (fungus)
• Leucosporidiella spp. (fungus)
• Wallemia spp. (fungus)
• Gluconacetobacter bacterial strain RG3T
• Candida famata (yeast)
• Candida guilliermondii (yeast)
• Candida obtusa (yeast)
• Kloeckera apiculata (yeast)
• Pichia burtonii (yeast)
• Pichia fermentans (yeast)
• Pichia membranaefaciens (yeast)
• Saccharomyces cerevisiae (yeast)
• Saccharomyces exiguus (yeast)
• Saccharomyces uvarum (yeast)
• Saccharomyces spp. (yeast)
• Schizosaccharomyces pombe (yeast)
• Zygosaccharomyces spp. (yeast)
• Gluconacetobacter saccharivorans (bacteria)
• Gluconacetobacter xylinus (bacteria)
• Tanticharoenia sakaeratensis (bacteria)
• Acetobacter lovaniensis (bacteria)
• Acetobacter peroxydans (bacteria)
• Acetobacter syzygii (bacteria)
• Acetobacter okinawensis (bacteria)
• Acetobacter tropicalis (bacteria)
• Gluconobacter cerinus (bacteria) 21
• Gluconacetobacter liquefaciens (bacteria)
• Gluconacetobacter oboedins (bacteria)
• Gluconacetobacter intermedius (bacteria)
• Gluconacetobacter europaeus (bacteria)
• Gluconacetobacter rhaeticus (bacteria)
• Gluconacetobacter hansenii (bacteria)
• Oenococcus oeni (bacteria)
• Lactobacillus satsumensis (bacteria)
• Lactobacillus nagelii (bacteria)
• Torulaspora microellipsoides (yeast)
• Candida boidinii (yeast)
• Pichia anomala (yeast)
• Zygotorulaspora florentina (yeast)
• Hanseniaspora valbyensis (yeast)
• Dekkera anomala (yeast)
• Dekkera bruxellensis (yeast)

The overall microbial composition of kombucha also varies depending on the tea, sweetener, other ingredients, and environmental conditions [12] [20] .

Researchers have also noted that kombucha species can vary based on their geographical origins [12] . 

People May Have Selectively Bred Kombucha for Hundreds of Years or Longer

One reason for geographical differences in kombucha strains could be that people have intentionally “bred” kombucha for specific purposes.

According to a 2019 peer-reviewed paper in Europe PMC, the long process of domesticating kombucha may have made kombucha species resistant to harmful or pathogenic species [21] . As a result, kombucha possesses properties that include activity against human pathogens and other “invaders” that could disrupt the fermentation process.

Equally fascinatingly, the authors speculate that “citizen scientists” may be able to continue to selectively breed kombucha for other special properties, like further antimicrobial properties or the production of special materials with medical uses.

By the same token, by testing different recipes and techniques and continuing to produce the ones you prefer, you can also breed and refine your own kombucha strains for optimal flavor, consistency, ease of production, and other properties.

 

4 Health Benefits of Kombucha

The science of kombucha is still in its infancy, and it doesn’t provide many definitive answers.

Along with the complex properties of kombucha cultures and kombucha, researchers are just beginning to investigate the potential health effects of drinking kombucha.

In most cases, scientists use cell studies (in vitro studies) or animal models rather than humans to investigate potential benefits of kombucha, when they do so at all.

Unfortunately, due to a lack of double-blind, placebo-controlled human clinical trials, kombucha isn’t yet supported by as much evidence as probiotic staples like yogurt and kefir.

The lack of evidence at this time certainly doesn’t mean there are no benefits, but it would be premature to say that the benefits of kombucha are fully demonstrated in studies so far. For best results, it’s recommended that you eat other probiotic foods and take probiotic supplements along with drinking kombucha.

Nonetheless, you’ll find some potential kombucha benefits according to peer-reviewed evidence below. 

#1: Kombucha has probiotic benefits.

Even though it hasn’t been studied as much as some probiotic foods, because kombucha contains many of the same probiotic Lactobacillus bacteria strains found in other probiotic foods, it stands to reason that kombucha offers similar probiotic benefits [15] .

Kombucha also contains Saccharomyces boulardii, a probiotic yeast that is shown in clinical trials to be beneficial for people with inflammatory gut disorders [22] .

Probiotic foods support gut health in a variety of ways, resulting in better digestion, lower inflammation levels in the digestive tract, enhanced immune function, and decreased side effects from antibiotic therapy such as antibiotic-associated diarrhea (AAD) [23] [24] . 

#2: Kombucha is rich in tea polyphenols and anti-inflammatory antioxidants.

Polyphenols are plant-based antioxidants found in green tea and other types of tea. Evidence suggests that polyphenols are responsible for many of the health benefits associated with drinking tea, such as a faster metabolism, less belly fat, lower cholesterol levels, and lower blood sugar [25] [26] [27] .

Because kombucha is made from tea, it also contains similar polyphenols, and likely offers similar health benefits. However, some research indicates that the detectable levels of polyphenols in kombucha actually increase over time relative to tea, possibly due to enzymatic changes that increase their availability [21] .

The microbial changes in kombucha may also create entirely new forms of antioxidants different from those found in regular tea, potentially with additional health benefits [21] . 

#3: Kombucha may have antimicrobial properties.

The microbial colonies in kombucha appear to have antimicrobial properties that can prevent bacteria that are potentially harmful to humans from growing [21] .

While it’s still not clear what this means for human health, some researchers think that kombucha could support a healthy balance of bacteria and other microorganisms in the body by preventing the growth of harmful bacteria [21] . 

#4: Kombucha Is Rich in B Vitamins and Ascorbic Acid

According to an analysis published in the International Journal of Food Science and Technology, kombucha made from black tea contains [28] :

• 0.74 milligrams per milliliter of vitamin B1
• 0.52 milligrams per milliliter of vitamin B6
• 0.84 milligrams per milliliter of vitamin B12
• and 1.51 milligrams per milliliter of vitamin C.

In other words, if you consume a 250 ml serving of kombucha, you’ll receive 185 mg of B1, 130 mg of B6, 210 mg of B12, and 380 mg of vitamin C–all of which would well exceed the recommended daily allowances of those vitamins for adults. 

Kombucha Safety, Caffeine, and Alcohol Content

When made correctly, kombucha is very likely safe for the vast majority of people.

However, like any food, especially fermented foods, it’s important to follow basic safety procedures.

Monitor your kombucha during and after production, always looking for any signs that could indicate a problem with the fermentation process.

If you notice mold, the safest thing to do is to throw your kombucha (including the affected SCOBY mother) away and start over.

Very rarely, serious adverse events have been reported after kombucha consumption, but the exact cause was never determined in each case, even after extensive investigation and testing by the FDA [29] [30] [31] .

Even though it’s unproven that kombucha was actually responsible for these rare events, some people remain wary.

According to one popular medical website, “Kombucha tea is often brewed in homes under non-sterile conditions, making contamination likely. When improperly manufactured ceramic pots have been used for brewing, lead poisoning has occurred — the acids in the tea can leach lead from the ceramic glaze.”

Based on peer-reviewed research, non-sterile conditions are unlikely to be a concern, due to the fact that healthy kombucha can prevent contamination under normal circumstances [21] .

And while such documented cases of lead poisoning have occurred, the improper fermentation vessels, not the kombucha, were the cause [32] .

Drinking kombucha is a personal decision, but it’s quite likely just as safe as any food, and safer than many due to its antimicrobial properties.

If you’re still not sure whether kombucha would be a good idea or not, consider asking your doctor for advice, especially if you have a medical condition or take prescription drugs. 

Caffeine Content

Traditional kombucha does contain low levels of caffeine, but unless you’re highly sensitive to caffeine, it’s unlikely to be a problem.

While many online sources claim that kombucha contains one-third the caffeine of tea, this number does not appear to be based on peer-reviewed evidence.

According to studies, the maximum caffeine degradation rate observed in kombucha was around 40% after 21 days [33] .

But after a more realistic 14-day period, one analysis found that the caffeine content was 33% lower than the starting levels (which were equivalent to black tea) [33] .

If you’re sensitive to caffeine, you can drink smaller servings of kombucha, ferment it with lower concentrations of tea, try making it with decaffeinated tea, or use herbal tea or another caffeine-free tea alternative. 

Alcohol Content

In the United States, kombucha with alcohol by volume (ABV) at or above 0.5% is taxed and regulated as an alcoholic beverage, so manufacturers do their best to stay under the limit [34] .

This means that in the US, drinking a 250 ml serving of commercial kombucha would be equivalent to slightly under one tenth of one standard alcohol beverage (a serving of beer, for example) at most.

However, in Australia, there is a voluntary compliance limit of 0.5% ABV for kombucha, and some commercial kombucha beverages exceed 1% [35] .

One study also found that with traditional methods (such as those used by kombucha brewers at home), kombucha ABV levels could get as high as 3.5% around day 7, then dipped slightly by day 14 to around 3% [8] .

While most study findings are lower than that, it’s clear that people who are sober or wish to avoid alcohol to the greatest extent possible should exercise caution with kombucha.

Yeast, sugar, temperature, and oxygen levels can all influence the alcohol content of kombucha. Try these suggestions if you prefer to minimize alcohol production as much as possible:

• Rinse your SCOBY mother between each batch to wash off yeast that may have accumulated.
• If your starter liquid appears cloudy or has filaments, run it through a clean coffee filter to filter out excess yeast.
• Try reducing total sugar content to 5% or less of recipes.
• Keep the ambient temperature as close as possible to 21 degrees Celsius (70 degrees Fahrenheit).
• Use a highly breathable cover and gently stir your kombucha mixture once or twice per day to ensure oxygenation [36] .
• Consider skipping the secondary fermentation step, as it may increase alcohol production.

Lastly, using tea alternatives may also help lower alcohol production while making kombucha. In particular, one study found that kombucha made with rooibos tea resulted in just 0.13% ABV, compared to 0.53% for green tea and 0.74% for black tea) [20] .

Final Thoughts Kombucha

is delicious, fascinating, fun, and easy to make at home–and very likely just as safe as any probiotic food.

Although the health benefits of kombucha aren’t as well-studied as those of many other probiotic foods, the chances are high that future studies will validate similar benefits as well as unique advantages to drinking kombucha.

In the meantime, the wisest strategy is to consider kombucha one part of your probiotic strategy, combining it with other proven sources of beneficial microbes such as kefir, water kefir, lacto-fermented vegetables, and probiotic supplements.

Either way, the endless variations of kombucha you can invent by combining different teas, sweeteners, and other ingredients are worthwhile in and of themselves and can provide a lifetime of experimentation and enjoyment.

If you’ve never made kombucha at home before, it’s one of the easiest ferments to make.

Instead of wasting money buying low-quality kombucha from the store, or spending time trying to track down someone willing to share a SCOBY daughter, start your own kombucha now with a high-quality Organic Kombucha Scoby or our Complete Kombucha Brewing Kit. 

 

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