Kombucha is the Western name for a fermentation of sweetened tea using lactobacilli and yeast cultures.

Biology of Kombucha

The tea contains a symbiosis of yeast species and acetic acid bacteria, mostly Bacterium xylinum. Species of yeast found in the tea can vary, and may include: Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe, Torulaspora delbrueckii and Zygosaccharomyces bailii. The culture itself looks somewhat like a large pancake, and is often mistakenly referred to as a mushroom.

Medical properties

No clinical studies have shown that Kombucha has any curative properties. Nonetheless, some people think Kombucha protects against cancer and other ailments. A review of the published science on Kombucha found that it may cause liver damage and one Kombucha drinker has died. ^*

Kombucha boasters believe it works by assisting in the phase II liver detoxification pathway, leading to efficient elimination of endogenous and exogenous bodily wastes. This hypothesis is due to the observation of increased glucuronic acid conjugates in the urine after kombucha consumption.

Early chemical analyses of kombucha brew suggested that glucuronic acid was a key component of the brew, perhaps assisting the liver by supplying more of the substance during detoxification. However, more recent analyses of kombucha offer a different explanation, as outlined in the book in Analysis of Kombucha Ferments by Michael Roussin. The author reports on an extensive chemical analysis of a variety of commercial and homebrew versions of kombucha, and finds no evidence of glucuronic acid at any concentration.

This author suggests, however, that another compound in Kombucha may have health benefits: D- glucaro- 1,4 lactone, otherwise known as glucaric acid. This compound serves as an inhibitor of the beta- glucuronidase enzyme, a bacterial product from the gut microbiota that can cleave the glucuronic acid conjugates. The activity of this bacterial enzyme has the effect of cleaving the glucuronic acid conjugates and sending bodily wastes back into circulation, thus increasing the exposure time before the waste is ultimately excreted. Therefore, the active component of kombucha likely exerts its effect by preventing bacterial disruption of glucuronic acid conjugates and increasing the detoxification efficiency of the liver.

Interestingly, glucaric acid is being explored independently as a cancer preventive agent. ^*

As a side note, persons at risk for increased intestinal permeability (and therefore, increased bacterial translocation from the gut), may be advised to avoid home-brewed versions of kombucha and other fermentation products with undefined microbial communities. This is simply a precautionary measure, since one or more undefined microorganisms from an otherwise innocuous drink could lead to opportunistic infection. In this case, other defined and well-studied probiotics (such as Lactobacilli) may be a better route for correcting problems related to increased intestinal permeability.

And as with all foods, care must be taken during preparation and storage to prevent contamination. Cleanliness is important during preparation of the tea, and in most cases, the acidity of the fermented drink will prevent growth of unwanted contaminants. In the event that mold does grow on the surface of the kombucha pellicle, or "mushroom," it's best to throw out the batch and start over. Reports of adverse reactions (although rare) may be related to unsanitary fermentation conditions, leaching of compounds from the fermentation vessels, or "sickly" kombucha cultures that cannot acidify the tea.

History and etymology

Its first recorded use is said to have been during the Qin Dynasty of China (221 BC), though the first confirmed evidence of its existence is of Russian origin and dates from the Early Modern Age, when tea first became affordable in Eastern Europe.

The name Kombucha is derived from the name of a Korean physician, Kom-bu, who introduced the drink to the Japanese Emperor Ingyō in the year 414 AD as a healing drink. The drink became known as Tsche of Kom-bu (Kombu cha).

To add confusion, Kombucha is a Japanese word denoting a tea-like infusion (cha) made from brown kelp (kombu). This Japanese Kombucha is not fermented and does not contain parts of the tea plant. It is not sweet, but sometimes it is salted. It tastes like a thin soup and it is a favourite food for convalescense of sick persons who cannot yet eat stronger food. The Japanese name for the drink made from the tea plant is koucha-kinoko, which means black tea mushroom.

The Russian "tea mushroom"

In Russia, Kombucha culture is used to make a popular fermented beverage. Since its introduction in the early 1900's after the Russo-Japanese War, Kombucha culture (called chayniy grib, чайный гриб - tea mushroom) became widely popular with Russians. The resulting drink is referred to as grib (гриб - mushroom) or "tea kvass" or simply "kvass", although it differs from regular kvass.

Preparation

There are (at least) two ways to prepare kombucha.

In one method, the beverage is made by placing the culture in a jar, usually a 3 liter glass container, then pouring in cold black tea with sugar. In about 8-12 days, the first portion of the beverage is ready; part of it is removed for consumption, and more tea with sugar is added to fill the jar. A mature kombucha is several centimeters thick and produces a portion of beverage every day. Once a month or two, the liquid needs filtering. If it becomes too sour, remove it, wash the kombucha in water and leave it for a night in clear water, then replace it with its usual sugared tea environment. As the kombucha slowly grows, from time to time slices are taken off it, which can be used to start new kombuchas in separate containers. Approximately ten percent of the liquid from each batch is typically kept as a "starter" liquid for the next preparation.

Another method allows for the bottling and saving of kombucha for later consumption. As in the previous method, the culture is placed into a large glass jar (gallon-sized pickle jars work very well). Boil 12 cups (about 3 liters) of water, then add one cup of white sugar and let the mixture boil for about five minutes. Next, remove from heat and add five tea bags (black or green only; do not use herbal teas). Let the tea steep (covered) until it reaches room temperature, and then pour it into the jar containing the kombucha culture. Cover the jar with a towel and let it sit for seven or eight days (may be slightly longer in colder environments). After this time, pour the kombucha drink into air-tight glass bottles (re-used sauce jars work well also), leaving enough tea with the culture so that it floats a couple of inches off the bottom (this is called the starter tea). Put the filled bottles in the refrigerator for a few days before consumption. This allows the flavor to deepen, and the natural carbonation to build up. Repeat the process as desired, but do not leave the kombucha culture in only the starter tea for longer than two weeks, as it will start to dry out.

Each time the kombucha culture goes through the fermentation process, it creates another layer. After three or four layers have built up, the tea will become sour and taste somewhat like vinegar. At this time, it is important to remove one or two of the layers, which are then either discarded or used to start a new batch.

In every step of the preparation process, it is important that hands and utensils (anything that is going to come into contact with the culture) are kept extremely clean so as not to contaminate the kombucha. As noted above, the only adverse reactions that have been observed in conjunction with kombucha use or preparation were connected to improper storage or contamination of the culture.

Trivia

Chef Josef Desimone of Google makes Kombucha for Google employees. Almost 100 glasses of Kombucha are served every day at Google cafeterias.

The popular alternative metal band System of a Down references Kombucha in the song "Sugar" on their self-titled album. Lead vocalist Serj Tankian screams, "The Kombucha Mushroom people sitting around all day."

References

• Dipti, et al. Lead induced oxidative stress: beneficial effects of Kombucha tea. Biomed Environ Sci. 2003 Sep;16(3):276-82.
• Ernst, et al. Kombucha: a systematic review of the clinical evidence. Forsch Komplementarmed Klass Naturheilkd / Research in Complementary and Classical Natural Medicine 2003;10:85-87.
• Pauline, et al. Studies on toxicity, anti-stress and hepato-protective properties of Kombucha tea. Biomed Environ Sci. 2001 Sep;14(3):207-13.
• Phan, et al. Lead poisoning from drinking Kombucha tea brewed in a ceramic pot. Med J Aust. 1998 Dec 7-21;169(11-12):644-6.
• Roussin, M., Analyses of Kombucha Ferments. 2003 http://www.kombucha-research.com/
• Teoh, et al. Yeast ecology of Kombucha fermentation. Int J Food Microbiol. 2004 Sep 1;95(2):119-26.
• Cutaneous anthrax associated with the Kombucha 'mushroom' in Iran. JAMA. 1998 Nov 11;280(18):1567-8.
• Frank, Günther W.: Kombucha - Healthy beverage and natural remedy from the Far East. Its correct preparation and use, Ennsthaler Gesellschaft GmbH & Co KG: 1995, ISBN 3-85068-337-0
• Frank, Günther W.: Kombucha - Mythos, Wahrheit, Faszination, Das biologisch aktive Naturgetränk. Was es für Sie persönlich tun kann (German language), Ennsthaler Gesellschaft GmbH & Co KG: 1991, ISBN 3-85068-555-1
• Frank, Günther W. How to make your own Kombucha Tea.
• "How To Make Kombucha" http://users.bestweb.net/~om/kmi/manual.html Recipe by Beverly Ferguson. 2003.
• "Kombucha Drops-Kombucha Extract" Article http://users.bestweb.net/~om/kmi/kombuchadrops.html

External links

• The Kombucha Journal in 29 languages
• The International Kombucha Exchange Here you will find helpful people, who give away Kombucha Babies, mostly for free or at low costs.
• kombucha.org, Worldwide distributors of Kombucha Cultures & ready made Kombucha Tea Note: This is a commercial site.
• FDA Fact Sheet
• Kombucha Center and FAQ
• Paper about the science, history and cultivation of Kombucha by mycologist, Paul Stamets
• Kombucha Manna Drops Note: This is a commercial site selling Organic Kombucha Manna Drops
• Kombucha and Waterkefir Note: This is a commercial site in Germany.
• Morbidity and Mortality Weekly Report December 08, 1995 / 44(48);892-893,899-900
• A good history of Kombucha by Dr. F.J. Perron
• Kombucha german niews

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