Kombucha



Kombucha is a drink made by fermenting black tea with a mish-mash of assorted fungus, mold, yeast, and bacteria that is allowed to float on top of the tea until the tea ferments. Yummy!

The kombucha mushroom people, sitting around all day…
This congealed clump of slimy little beasties that forms on top of the tea is called a "kombucha mushroom"; however, it is not in any meaningful sense a mushroom, but a polyculture of various microorganisms. What critters wind up in said clump of gunk varies from batch to batch and place to place, but acetobacteria (creating vinegar) and yeasts of various species seem to be a constant. Thus the fermented kombucha usually contains a mix of several vinegars, a small amount of alcohol, "live cultures", and who knows what else. It usually has a slight carbonation. The amount of alcohol is usually under 0.5% (roughly 1/8th as a much as a light beer), but is sometimes a bit higher. The cutoff of 0.5% is when the US Alcohol and Tobacco Tax and Trade Bureau takes notice, and some jurisdictions actually ban sale to minors.

Unsurprisingly, kombucha is Yet Another Untested Cancer Cure™ that also cures everything else. Specifically, it is falsely touted by its promoters as also being able to cure arthritis, AIDS, asthma, bronchitis, flu, warts, irritable bowel syndrome, and chronic fatigue syndrome.

Truth be told, polycultures can be very difficult to manage, and kombucha consumers always run the risk of the organisms within being knocked out of equilibrium or being contaminated. One of these days a batch of kombucha is going to wind up contaminated with E. coli or anthrax or something like that. It hasn't happened yet but if you don't want to take the chance of being the first to find out when it does, try this recipe for fake kombucha instead.

Kombucha has also been linked to two cases of metabolic acidosis by the CDC in 1995, one fatal and the other nearly so. Two women in northwestern Iowa had been consuming kombucha daily from the same mother culture for two months. No toxic organisms were present in the tea or the patients.

Kombucha, as a fermented beverage, can get a bit unstable when shaken. If you have any bottles of the stuff that you think might have been shaken, you should open them pointing away from your face.

Common mistake
In Japan, Konbucha (昆布茶, "kelp tea") stands for a different beverage made from dried and powdered kombu (an edible kelp from the Laminariaceae family). The Kombucha mentioned above is called "kōcha kinoko" in Japan, but is neither well known nor particularly popular there.

Better live cultured foods to play with
If you're into the whole live culture thing but don't feel like messing with squicky and potentially toxic polycultures of questionable provenance, RationalWiki offers the following list of better live cultured foods to have around:
 * Bottle-conditioned beer
 * Yogurt
 * Sourdough starter (see also )
 * Blue cheese
 * Kefir

Literature

 * Mayser P, Fromme S, Leitzmann C, Gründer K: The yeast spectrum of the 'tea fungus Kombucha'. Mycoses 38: 289-295, 1995
 * MMWR: Unexplained severe illness possibly associated with consumption of kombucha tea - Iowa 1995. J Am Med Assoc 275: 96-98, 1996
 * Perron AD, Patterson JA, Yanofsky NN: Kombucha 'mushroom' hepatotoxicity. Ann Emergency Med 26: 660-661, 1995
 * Phan TG, Estell J, Duggin G, Beer I, Smith D, Ferson MJ: Lead poisoning from drinking Kombucha tea brewed in a ceramic pot. Med J Aust 169: 644-646, 1998
 * Sadjadi J: Cutaneous Anthrax associated with the kombucha 'mushroom' in Iran. J Am Med Assoc 280: 1567-1568, 1998
 * Srinivasan R, Smolinske S, Greenbaum D: Probable gastrointestinal toxicity of kombucha tea. Is this beverage healthy or harmful? J Gen Internal Med 12: 643-645, 1997