In 220 BC, Tsin Dynasty China created and cherished a homemade beverage, prized for its detoxifying and energizing properties (Roche 1998). What they termed the Divine Che, is also known as kombucha, the product of the fermentation of tea and sugar by a symbiotic association of bacteria and yeast, forming a tea fungus. Black tea and white sugar are the best substrates for the preparation of kombucha, however green tea can also be used (Reiss 1994). Tea leaves are infused in boiling water for 10 minutes and then removed, followed by the addition of 50 g/l of sugar (Dufresne and Farnworth 2000). Once the tea is cooled, it is poured into a clean glass container where it is acidified by the addition of vinegar or previously prepared kombucha. The tea fungus is laid on the tea surface, and the jar is then covered, sealed, and allowed to incubate at room temperature for 1-8 weeks. Flavor is dependent upon the amount of time allowed for fermentation, with a pleasant, lightly sparkling, sourish fruity taste developing after a few days which turns to mild vinegar taste with prolonged incubation (Dufresne and Farnworth 2000). During this fermentation process, a daughter tea fungus is formed at the tea surface, which is removed and stored in a small amount of fermented tea for later fermenting processes. The liquid is passed through cheesecloth where it is then bottled and securely capped. 

The main metabolites identified in kombucha are acetic acid, lactic acid, gluconic acid, and glucuronic acid, along with ethanol and glycerol (Blanc 1996). The composition and concentration of these metabolites is dependent upon the source of the tea fungus, sugar concentration, and the amount of time allowed for fermentation. Yeast and bacteria within the tea fungus utilize the substrates in different yet complimentary ways. Sucrose is hydrolyzed by yeast cells to yield glucose and fructose, producing ethanol as a byproduct (Sievers et al. 1995). Acetic bacteria convert glucose to gluconic acid and ethanol to acetic acid. The overall fermentation process stimulates the synthesis of the B complex of vitamins and folic acid, as well as causes a decrease in pH as a result of increased concentrations of organic acids (Roche 1998, Blanc 1996).

The wide range of health benefits associated with kombucha have been reported for centuries all throughout the world. Documentation of Russian use of kombucha during World War I called the beverage the “Russian secret home remedy” and a “Wonderdrink,” reporting its use for headaches, gastric illnesses, and regulation of intestinal activities that were often disturbed by lifestyles in the army (Allen 1998). By 1925, medical studies began reporting additional beneficial effects as aided by kombucha, including antibiotic properties, regulation of gastric, intestinal and glandular activities, relief of joint rheumatism, gout and hemorrhoids, positive influence on cholesterol levels, arteriosclerosis, toxin excretion and blood cleansing, diabetes, nervousness, and aging problems (Dufresne and Farnworth 2000). A population study conducted in Russia in 1951 even found daily consumption of kombucha to be correlated with an extremely high resistance to cancer. Later research reaffirmed claims of such cancer healing properties, reporting the detoxifying effects of kombucha as well as its stimulation of the immune system and increased productions of interferon. Typically, cancer patients have abnormal blood pH levels and concentrations of lactic acid, and kombucha has been observed to re-equilibrate these parameters (Roche 1998). More recent studies have reported the production of acetic acid during the fermentation process to be responsible for the antibiotic activity against bacteria such as Helicobacter pylori, Esherichia coli, Staphylococcus aureus and Agrobacterium tumefaciens, as the acetic acid has been shown to inhibit fungal growth and can present mild activity at low pH against lactic acid bacteria (Steinkraus et al. 1996, Matsuda et al. 1994).

The acidic composition of kombucha is said to be responsible for the majority of its medicinal properties. Its detoxifying properties are due to the ability of glucuronic acid to bind to toxin molecules and increase their excretion by the kidneys or the intestines (Dufresne and Farnworth 2000). It is in this way that disorders caused by the accumulation of toxins, such as gout, rheumatism, arthritis and kidney stones, are relieved. Concentrations of lactic acid are also said to be responsible for kombucha’s laxative and immunostimulatory effects (Reiss 1994). Additional medicinal properties of kombucha include stimulation of digestion, improvement of liver function, and enhancement of general metabolism. The beneficial impacts produced by this probiotic miracle elixir are even accompanied by slightly more outrageous claims made by avid enthusiasts, which include elimination of gray hair, increased sex drive, and improvement of eyesight as well as reports of its use as a household cleaner, underarm deodorant and soothing foot soak (Ferguson and Estelle 1998).

Literature Cited

Allen C. M. 1998. Past research on kombucha tea. The Kombucha FAQ Part 6. Research and tests results. <http://persweb.direct.ca/chaugen/kombucha_faq_part06.html.>

Blanc P. J. 1996. Characterization of the tea fungus metabolites. Biotechnology Letters 18: 139-142.

Dufresne C. and E. Farnworth. 2000. Tea, kombucha, and health: a review. Food Research International 33: 409-421.

Ferguson B. and A. Estelle. 1998. Benefits of kombucha. <http://bawue.de/~kombucha/benefits.htm>

Matsuda T., T. Yano, A. Maruyama, and H. Kumagai. 1994. Antimicrobial activities of organic acids determined by minimum inhibitory concentrations at different pH ranged from 4.0 to 7.0. Journal of the Japanese Society of Food Science Technology 41: 687-702.

Reiss J. 1994. Influence of different sugars on the metabolism of the tea fungus. Zeitschrift fur Lebensmittel-Untersuchung und-Forschung 198: 258-261.

Roche J. 1998. The history and spread of kombucha. <http://w3.trib.com~kombu/roche.html.>

Sievers M., C. Lanini, A. Weber, U. Schuler-Schmid, and M. Teuber. 1995. Microbiology and fermentation balance in kombucha beverage obtained from a tea fungus fermentation. Systematic and Applied Microbiology 18: 590-594.

Steinkraus K. H., K. B. Shapiro, J. H. Hotchkiss, and R. P. Mortlock. 1996. Investigations into the antibiotic activity of tea fungus/kombucha beverage. Acta Biotechnologica 16: 199-205.