What Is Kombucha?

Kombucha is a fermented tea beverage that has gained popularity over the years. Fermentation occurs when microorganisms like yeast and bacteria break sugars down into other simpler substances. This process is used to create foods and beverages like beer, wine, bread, kimchi, yogurt, and, of course, kombucha.

You can purchase it by the bottle in countless flavors at most grocery stores or make your own at home. Beyond its delightfully tangy taste, kombucha offers health benefits and is a good source of probiotics and antioxidants. 

Kombucha is made with a symbiotic culture of bacteria and yeast (SCOBY) that is often referred to as the “mother,” similar to the “mother” found in vinegar. The SCOBY is added to brewed black or green tea along with sugar, fermentation takes place, and voila—kombucha tea is made! While homemade kombucha traditionally isn’t carbonated, many store-bought brands add carbonation for a fizzy soda pop-like experience. 

Kombucha’s History

Kombucha originated around 200 B.C. in Northeast China and was originally consumed for its healing properties. Kombucha gained popularity and spread to Russia and other parts of Eastern Europe and Germany before making its way to the United States in the early 21st century. Today you can find kombucha in almost any grocery store!

5 Health Benefits of Kombucha

Kombucha’s health benefits are largely due to fermentation, which produces a probiotic-rich beverage. Kombucha’s health benefits also stem from it being a tea-based beverage. While kombucha can be made with any caffeinated tea, including white, black, oolong, or green, research suggests kombucha made from green tea offers the most benefits.  

Below are the evidence-based health benefits of drinking kombucha. 

1. Packed With Probiotics

Kombucha, like many fermented foods, is a good source of probiotics.¹ Probiotics are bacteria and yeasts that offer health benefits when consumed. Consuming foods naturally rich in probiotics, such as kombucha, kimchi, sauerkraut, and sourdough, can support microbial diversity within your gut and overall gut health. Gut health matters because gut health impacts immune health—in fact, 70 to 80% of immune cells reside in the gut.² A healthy gut also supports bowel regularity, digestion, cognitive function, and immune health.

2. Antioxidant-rich

Kombucha made with green tea is rich in antioxidant compounds known as polyphenols, which are abundant in green tea. Drinking green tea may help reduce the risk of chronic disease.^{3, 4, 5} Regular consumption of green tea may also support cognitive function, help manage blood sugar levels, and help burn fat.^{6, 7} 

3. Supports Heart Health

Green tea drinks like kombucha have been shown to help lower the risk of heart disease.⁸ Researchers believe this may be due to the antioxidant compounds found in green tea. 

4. Supports Better Blood Sugar Levels

Green tea has also been shown to have a beneficial effect on blood sugar levels.⁹ However, since some kombuchas may be high in sugar, check the nutrition label and choose a kombucha with no sugar added after fermentation.

5. Supports Metabolic Function

Green tea contains epigallocatechin-3-gallate, also known as EGCG. EGCG acts as a powerful antioxidant that fights free radical damage. EGCG also has anti-inflammatory properties and may help to suppress the action of pro-inflammatory chemicals within the body.¹⁰ 

Kombucha Side Effects

Kombucha has become popular as a healthier beverage option. While Kombucha may be more nutritious than high-sugar sodas, it does contain caffeine, sugar, and limited amounts of alcohol as a result of fermentation. Keep these cautions in mind and consume kombucha in moderation.

High in Added Sugar

Depending on the brand, some store-bought kombuchas may be high in added sugar. Always read the ingredient list and nutrition facts panel to choose a kombucha with little added sugar. 

Mold and Bad Bacteria

Proper fermentation and cleanliness are essential for avoiding harmful bacterial growth, particularly in homemade kombucha. Sanitize all glassware properly, wash your hands frequently, and sterilize your workspace to reduce the risk of mold or other harmful bacteria growth.

Alcohol Content

Kombucha naturally contains alcohol as a byproduct of fermentation. Most store-bought kombucha contains .5% or less alcohol, so it can be sold as a non-alcoholic beverage. For reference, traditional beer contains approximately 4.5% alcohol. 

Always check the ingredient label for alcohol content to know exactly how much is in the kombucha you are drinking. And keep in mind that some brands purposely make a higher alcohol level kombucha as an alternative to beer. 

Homemade kombucha contains a small amount of alcohol as well—typically between 1% to 2.5% alcohol content. 

Carbonation

Those with IBS or other digestive symptoms may want to limit kombucha consumption since added fruit juice and carbonation can exacerbate digestive issues like gas and bloating in some people.

Ingredients to Make Kombucha

• SCOBY: The symbiotic culture of bacteria and yeast has an orange-yellow jelly-like consistency. If you have a friend who makes kombucha, peel a layer known as a “baby” from their SCOBY “mother.” You can also purchase a SCOBY from a health food store, online, or even make one at home from scratch. 
• Filtered Water: Filtered water or spring water works best. Avoid tap water when possible.
• Sugar: Cane sugar, turbinado, or brown sugar work best. Avoid artificial sweeteners, maple syrup, honey, or agave. 
• Caffeinated Tea: Black tea, white tea, or green tea work best. Avoid herbal teas or tea with essential oils, which may interfere with the fermentation process and lead to bacteria or mold growth. 
• Prepared Kombucha: Unflavored store-bought or homemade kombucha can be used as a starter for your own kombucha. Avoid flavored kombucha, which may introduce bad bacteria and increase the risk of mold growth. 

You can also look for starter kits online or kombucha powders if you’d rather not make your own kombucha at home!

Homemade Kombucha Tips

• Use glass containers: Metal can interact with the acidity in kombucha and harm your SCOBY. Plastic can be porous and introduce harmful bacteria. 
• Temperature matters: Fermentation thrives in warmer weather. If your home is chilly or it’s a cold season, fermentation may still occur but at a slower pace.
• Avoid mold: If you see green, white, or black spots growing on your SCOBY, toss the whole batch.  
• Keep it clean: One of the best ways to reduce the risk of mold growth is to keep all supplies and workspaces clean! 

How to Make Homemade Kombucha

This recipe makes one gallon or 32 half-cup servings:

Ingredients:

• 1 SCOBY
• 3 ½ quarts of filtered water
• 1 cup of cane sugar
• 8 caffeinated tea bags (green, white, or black tea all work)
• 2 cups of unflavored kombucha, store-bought or homemade

Directions:

1. Bring 1 quart of water to a boil.
2. Stir in sugar and let it dissolve.
3. Add tea bags and let steep for 10 minutes.
4. In a clean one-gallon jar, combine 1 quart of sugar-tea mix with the remaining 2 ½ quarts of filtered water along with the SCOBY.
5. Cover the jar lid with a cloth and rubber band to allow airflow but prevent bugs or bacteria from getting in.
6. Place in a cupboard or somewhere out of direct sunlight.
7. The ideal temperature for kombucha fermentation is between 70 to 75 degrees Fahrenheit.
8. Let the kombucha ferment on a counter or in a cabinet out of direct sunlight for 7 to 14 days. On day seven, start tasting the tea by pouring a small sample into a glass. It will taste sweet at first, but the longer it ferments, the more tart your kombucha will taste with a classic vinegar kombucha flavor profile.
9. When you’ve achieved the flavor you like, pour the kombucha into jars and refrigerate. 
10. With clean hands, place the SCOBY in a new clean jar and pour over with some of the recently made Kombucha. Keep stored in a cupboard or out of direct sunlight and use it for your next batch.  

How to Naturally Flavor Kombucha

Once kombucha has fermented and the SCOBY is safely removed, you can add fresh juice to naturally add flavor. Blueberry juice, tart cherry juice, pomegranate juice, ginger juice, orange juice, and other juices are all delicious additions that make for tasty kombucha! 

Why Drink Kombucha

Kombucha is a good source of probiotics and, when made with green tea, provides antioxidants like polyphenols that support cognitive function, help manage blood sugar, and support heart health. The EGCGs found in green tea also have anti-inflammatory properties. You can buy kombucha at most grocery stores, make your own at home, or enjoy a powder version mixed with water! 

If you’re considering adding kombucha to your wellness routine for its health benefits, talk with a Registered Dietitian Nutritionist who can review your health history, dietary intake, and provide individualized dietary feedback. 

References:

1. Chakravorty S, Bhattacharya S, Chatzinotas A, Chakraborty W, Bhattacharya D, Gachhui R. Kombucha tea fermentation: Microbial and biochemical dynamics. Int J Food Microbiol. 2016;220:63-72. 
2. Wiertsema SP, van Bergenhenegouwen J, Garssen J, Knippels LMJ. The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies. Nutrients. 2021 Mar 9;13(3):886. 
3. Kurahashi N, Sasazuki S, Iwasaki M, Inoue M, Tsugane S; JPHC Study Group. Green tea consumption and prostate cancer risk in Japanese men: a prospective study. Am J Epidemiol. 2008;167(1):71-77. 
4. Sun CL, Yuan JM, Koh WP, Yu MC. Green tea, black tea and breast cancer risk: a meta-analysis of epidemiological studies. Carcinogenesis. 2006;27(7):1310-1315. 
5. Yang G, Shu XO, Li H, et al. Prospective cohort study of green tea consumption and colorectal cancer risk in women. Cancer Epidemiol Biomarkers Prev. 2007;16(6):1219-1223. 
6. Liu K, Zhou R, Wang B, et al. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr. 2013;98(2):340-348. 
7. Nagao T, Hase T, Tokimitsu I. A green tea extract high in catechins reduces body fat and cardiovascular risks in humans. Obesity (Silver Spring). 2007;15(6):1473-1483. 
8. Kuriyama S. The relation between green tea consumption and cardiovascular disease as evidenced by epidemiological studies. J Nutr. 2008;138(8):1548S-1553S. 
9. Liu K, Zhou R, Wang B, et al. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr. 2013;98(2):340-348. 
10. Ohishi T, Goto S, Monira P, Isemura M, Nakamura Y. Anti-inflammatory Action of Green Tea. Antiinflamm Antiallergy Agents Med Chem. 2016;15(2):74-90.