Kombucha

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Kombucha is the Western name for sweetened tea that has been fermented by a macroscopic solid mass of microorganisms called a "kombucha colony," usually consisting principally of Bacterium xylinum and yeast cultures.

The kombucha culture looks a bit like a large pancake. A healthy, new culture is light in color, and will generally darken with age.

1 Biology of kombucha
2 Medical properties
3 History and etymology
4 The Russian "tea mushroom"
5 Preparation
6 Trivia
7 References
8 External links

[edit] Biology of kombucha

See also: Tibicos

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.

[edit] Medical properties

Advocates believe kombucha 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 analysis 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 analysis of kombucha offer a different explanation, as outlined in the book in Analysis of Kombucha Ferments by Michael Roussin[1]. 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. [2]

No clinical studies have been performed that demonstrate any specific curative properties of kombucha, but anecdotal reports suggest protection against cancer and other ailments. A review of the published literature on the safety of kombucha suggests no specific oral toxicity in rats[3], although other reports suggest that care should be taken in humans when combined with medical drugs, hormone replacement therapy, etc[4]. Indeed, if kombucha contributes to increased drug clearance via beta-glucuronidase inhibition, then kombucha consumption would likely alter the effectiveness of medications. In addition, persons should be aware of potential allergic reactions or other complications, and should discontinue use or consult a medical professional if complications arise[5].

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 may be related to unsanitary fermentation conditions, leaching of compounds from the fermentation vessels[6], or "sickly" kombucha cultures that cannot acidify the brew.

[edit] History and etymology

The first confirmed evidence of the existence of Kombucha is Russian origin and dates from the Early Modern Age, when tea first became affordable in Eastern Europe.

The word kombucha (昆布茶) in Japanese refers to a different item: tea (cha) made from kelp (kombu), or a tea-like infusion made from brown kelp, in either powdered or finely cut form. It is not fermented and does not contain parts of the tea plant. It is not sweet, and usually salted. It tastes like a thin soup and it is a favorite food for convalescence of sick persons who cannot yet eat stronger food. The Japanese name for the drink made from the tea plant is kōcha-kinoko (紅茶キノコ), which means black tea mushroom.

Though many people refer to the actual Kombucha as a mushroom, it is in fact a Symbiotic Colony of Bacteria and Yeast, or SCOBY for short.[7]

[edit] The Russian "tea mushroom"

In Russia, Kombucha culture is used to make a popular fermented beverage. Since its introduction in the early 1900's, 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.

[edit] Preparation

During each fermentation cycle, the original culture settles, and a new layer of the kombucha culture grows just below the surface of the tea mixture.

There are many 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 but this is optional. Some people use apple-cider vinegar, about 1/4 cup, to prime the tea.

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 of green tea or black tea. Herbal teas are not suitable for this process. 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 one new "mushroom" layer which will form atop of the original, if used. After three or four layers have built up, the tea will become sour and taste somewhat like vinegar. It is not recommended to allow this to occur. When the new batch is ready, one may either use the second layer to start another batch, along with the original one for its own batch or it may be thrown away, (may be used for fertilizer). Each mushroom can be used over and over again but most people discard an older mushroom and use the newer mushroom to make their next batch of tea only because the newer mushroom looks younger and fresher to them. Older mushroom are not less effective in brewing a batch of tea than a newer mushroom.

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 dish soap clean so as not to contaminate the kombucha.

For safety reasons Kombucha should be brewed in food-grade glass containers only; a glass gallon size pickle jar works well. Kombucha should not be brewed in lead crystal, ceramic, plastic, painted, or metallic containers including stainless steel. (The acids formed during the fermentation process will react with the metal, ceramic glazes may contain trace metals, and plastic may leech by-products into the finished product.) You may, however, make the tea & sugar solution for your new batch in a metal cooking container. Then add your tea/sugar solution to a clean glass container along with the kombucha culture and starter liquid. Günther, Frank (1995). Kombucha - Healthy beverage and natural remedy from the Far East. Its correct preparation and use (in English). Ennsthaler Gesellschaft GmbH & Co. ISBN 978-3850683371. ^{[citation needed]}

Making kombucha is an easy way to provide the body with pro-biotics, organic acids, and other nutrients. It has been used for hundreds of years for it health promoting benefits and is consumed daily by thousands of people around the world.

[edit] 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."

Singer-songwriter and guitarist M. Ward listed Kombucha as his "best purchase of the past year" in 2006, stating that "It's an acquired taste, but they tell me it rejuvenates, restores, revitalizes and replenishes." [8]

On an episode of MTV Cribs featuring the home of surfer Laird Hamilton and volleyball player and model Gabrielle Reese, their refrigerator opened to reveal several bottles of "Kombucha Wonder Drink", a bottled tea drink containing Kombucha. Reese removed a bottle and displayed it to the camera, stating that Kombucha is "a very good healthy drink, it helps support mental health and gives energy."[9]

[edit] 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.
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.
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 978-3850683371
"How To Make Kombucha" http://users.bestweb.net/~om/kmi/manual.html Recipe by Beverly Ferguson. 2003.