Kombucha
Kombucha is a fermented, effervescent and sweetened black tea drink. Sometimes the beverage is called kombucha tea to distinguish it from the culture of bacteria and yeast. Juice, spices, fruit, or other flavorings are often added. Commercial kombucha contains small amounts of alcohol.
Kombucha is believed to have originated in China, where the drink is traditional. While it is named after the Japanese term for kelp tea in English, the two drinks have no relation. By the early 20th century kombucha spread to Russia, then other parts of Eastern Europe and Germany. Kombucha is now homebrewed globally, and also bottled and sold commercially. The global kombucha market was worth approximately billion as of 2019.
Kombucha is produced by symbiotic fermentation of sugared tea using a symbiotic culture of bacteria and yeast commonly called a "mother" or "mushroom". The microbial populations in a SCOBY vary. The yeast component generally includes Saccharomyces cerevisiae, along with other species; the bacterial component almost always includes Gluconacetobacter xylinus to oxidize yeast-produced alcohols to acetic acid. Although the SCOBY is commonly called "tea fungus" or "mushroom", it is actually "a symbiotic growth of acetic acid bacteria and osmophilic yeast species in a zoogleal mat ". The living bacteria are said to be probiotic, one of the reasons for the popularity of the drink.
Numerous health benefits have been claimed to correlate with drinking kombucha; there is little evidence to support any of these claims. The beverage has caused rare serious adverse effects, possibly arising from contamination during home preparation. It is not recommended for therapeutic purposes.
History
Kombucha likely originated in the Bohai Sea region of China. At least before the 20th century, some traditional Chinese medicine practitioners used it as a remedy for lung and stomach ailments, but the drink was not widely known across the country. It spread to Russia before reaching Europe and gained popularity in the United States in the early 21st century. In the intervening years, its popularity in the West eclipsed its popularity in China, where it remains less known, though consumption is increasing in many East Asian countries. With an alcohol content under 0.5%, it is not federally regulated in the U.S.There are numerous myths surrounding the history of kombucha, likely invented in the West as a marketing gimmick. There is no evidence that kombucha originated in Qin dynasty China and that it was served to Emperor Qin Shi Huang. Furthermore, there is no evidence that kombucha was ever present in Korea or Japan before the late 20th century, making claims that a Korean doctor named Kombu served the drink to Japanese Emperor Ingyo entirely apocryphal.
Kombucha was first introduced to Japan from Russia and became a health fad in the country following the publication of Sumako Nakamitsu's 1974 bestseller, Kōcha Kinoko Health Methods. Although kombucha had already been consumed in China before it became known in Japan, overseas interest in the beverage for its purported wellness benefits contributed to increased attention and consumption in China during the 1980s.
Prior to 2015, some commercially available kombucha brands were found to contain alcohol content exceeding this threshold, sparking the development of new testing methods. With rising popularity in developed countries in the early 21st century, kombucha sales increased after it was marketed as an alternative to beer and other alcoholic drinks in restaurants and pubs.
According to the market research firm Grand View Research, kombucha had a global market size of billion as of 2019, and this is expected to grow to billion by 2030.
Etymology and terminology
The etymology of kombucha is uncertain, but it is believed to be a misapplied loanword from Japanese. English speakers may have confused the Japanese word konbucha with, popularized around 1975. In Japanese, the term refers to a kelp tea made with konbu and is a completely different beverage from the fermented tea usually associated with kombucha elsewhere in the world.Merriam-Webster's Dictionary suggests kombucha in English arose from misapplication of Japanese words like, 'tea made from kelp',, from 'kelp', + 'tea'. The American Heritage Dictionary notes the term might have originated from the observation that the gelatinous film of kombucha resembled seaweed. The first known use in the English language of the word appeared in the British Chemical Abstracts in 1928.
In Chinese, kombucha was historically known as hǎibǎo, derived from the SCOBY's resemblance to a jellyfish, and wèibǎo, referring to its perceived medicinal benefits. Today, it is commonly called hóngchá jūn, a term based on the Japanese kōcha kinoko.
Composition and properties
Biological
A kombucha culture is a symbiotic culture of bacteria and yeast, similar to mother of vinegar, containing one or more species each of bacteria and yeasts, which form a zoogleal mat known as a "mother". There is a broad spectrum of yeast species spanning several genera reported to be present in kombucha cultures, including species of Zygosaccharomyces, Candida, Kloeckera/Hanseniaspora, Torulaspora, Pichia, Brettanomyces/Dekkera, Saccharomyces, Lachancea, Saccharomycoides, Schizosaccharomyces, Kluyveromyces, Starmera, Eremothecium, Merimbla, Sugiyamaella.The bacterial component of kombucha comprises several species, almost always including the acetic acid bacteria Komagataeibacter xylinus, which ferments alcohols produced by the yeasts into acetic and other acids, increasing the acidity and limiting ethanol content. The population of bacteria and yeasts found to produce acetic acid has been reported to increase for the first 4 days of fermentation, decreasing thereafter. K. xylinus produces bacterial cellulose, and is reportedly responsible for most or all of the physical structure of the "mother", which may have been selectively encouraged over time for firmer and more robust cultures by brewers. The highest diversity of kombucha bacteria was found to be on the 7th day of fermentation with the diversity being less in the SCOBY. Acetobacteraceae dominate 88 percent of the bacterial community of the SCOBY. The acetic acid bacteria in kombucha are aerobic, meaning that they require oxygen for their growth and activity. Hence, the bacteria initially migrate and assemble at the air interface, followed by the excretion of bacterial cellulose after about 2 days.
The mixed, presumably mutualistic culture has been further described as being lichenous, in accord with the reported presence of the known lichenous natural product usnic acid, though as of 2015, no report appears indicating the standard cyanobacterial species of lichens in association with kombucha fungal components.
Chemical composition
Kombucha is made by adding the kombucha culture into a broth of sugared tea. The sugar serves as a nutrient for the SCOBY that allows for bacterial growth in the tea. Sucrose is converted, biochemically, into fructose and glucose, and these into gluconic acid and acetic acid. In addition, kombucha contains enzymes and amino acids, polyphenols, and various other organic acids which vary between preparations.Other specific components include ethanol, glucuronic acid, glycerol, lactic acid, and usnic acid.
The alcohol content of kombucha is usually less than 0.5%, but increases with extended fermentation times. Some tests have found commercial kombuchas with a range of alcohol contents ranging from undetectable to 4%. The concentration of alcohol, specifically ethanol, increases initially but then begins to decrease when acetic acid bacteria use it to produce acetic acid. Over-fermentation generates high amounts of acids similar to vinegar. The pH of the drink is typically about 3.5.
Nutritional content
Kombucha tea is 95% water and contains 4% carbohydrates and several B vitamins, such as thiamin, riboflavin, niacin, and vitamin B6.Production
Kombucha can be prepared at home or commercially. It is made by dissolving sugar in non-chlorinated boiling water. Tea leaves are then steeped in the hot sugar water and discarded. The sweetened tea is cooled and the SCOBY culture is added. The mixture is then poured into a sterilized beaker along with previously fermented kombucha tea to lower the pH. This technique is known as "backslopping". The container is covered with a paper towel or breathable fabric to prevent insects, such as fruit flies, from contaminating the kombucha.The tea is left to ferment for a period of up to 10 to 14 days at room temperature. A new "daughter" SCOBY will form on the surface of the tea to the diameter of the container. After fermentation is completed, the SCOBY is removed and stored along with a small amount of the newly fermented tea. The remaining kombucha is strained and bottled for a secondary ferment for a few days or stored at a temperature of 4 °C.
Commercially bottled kombucha became available in the late 1990s. In 2010, elevated alcohol levels were found in many bottled kombucha products, leading retailers including Whole Foods to pull the drinks from store shelves temporarily. In response, kombucha suppliers reformulated their products to have lower alcohol levels.
By 2014, US sales of bottled kombucha were $400 million, $350 million of which was by Millennium Products, Inc. which sells GT's Kombucha. In 2014, several companies that make and sell kombucha formed a trade organization, Kombucha Brewers International. In 2016, PepsiCo purchased kombucha maker KeVita for approximately $200 million. In the US, sales of kombucha and other fermented drinks rose by 37 percent in 2017. Beer companies like Full Sail Brewing Company and Molson Coors Beverage Company produce kombucha by themselves or via subsidiaries.
As of 2021, the drink had some popularity in India's National Capital Region, partly due to its success in the west.