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Kombucha is a lightly effervescent, cider-like beverage, made by fermenting sweetened tea. It is produced using a starter culture of bacteria and yeasts called a SCOBY (Symbiotic Colony of Bacteria and Yeast). A mature SCOBY resembles a flat, jelly-like pancake, often referred to as a 'mushroom' or 'tea fungus' due its unique appearance, although it is not a mushroom.
Kombucha contains live beneficial bacteria and yeasts, organic acids, B vitamins, antioxidants, and trace minerals. Added juice or flavorings may contribute nutrients as well. With only about 30 calories and 2-3 grams of sugar per 8 ounces of unflavored kombucha, kombucha can be a refreshing, low calorie beverage.
Health impacts attributed to kombucha vary widely, from claims of multiple therapeutic effects, such as improved digestion, gut health, and immune function, to adverse reactions if acid levels become unusually high. Only limited scientific research is available to help answer questions about the benefits and safety of kombucha.
Maintain safe and hygienic practices, such as following proper steps and keeping a clean environment, to minimize risk of contaminants such as molds or harmful bacteria which could cause illness. Always wash hands well and rinse with kombucha or vinegar before handling the SCOBY. First, obtain a SCOBY and starter liquid, either from a friend's mature starter or purchased fresh online. The SCOBY and liquid are added to a food-grade vessel of brewed, cooled, sugar-sweetened tea, then lightly covered and allowed to ferment at room temperature, typically for 7-10 days but possibly up to one month. The liquid acidifies the tea to assure a safe pH level and minimize contamination, while the sugar feeds the bacteria and yeast, producing an acidic end product which tastes a bit like cider vinegar, typically with slight carbonation and trace amounts of alcohol. Fruit juice or other flavorings may then be added as desired.
When consuming any new food or beverage, start small (up to 4 ounces per day with plenty of water) and observe your own body's results. Under some conditions, the alcohol level may exceed 0.5 percent alcohol by volume, which surpasses the limit for non-alcoholic beverages. If any signs of spoilage are noted, such as fuzzy blue, gray, green, brown, or black mold, discard the SCOBY and kombucha, and thoroughly wash vessel.
Ingredients for 1 gallon:
Repeat batches using continuous brew technique:
To minimize handling the SCOBY and reduce introduction of contaminants, it is better to leave the SCOBY and starter liquid in the vessel and not wash the vessel between uses, but only if it becomes built up with yeast. Gently pour in new sweetened, cooled tea along the inside of the jar to limit disturbing the SCOBY. SCOBY growth can be peeled and shared with others or stored for several weeks in a similar cloth covered vessel, covered by kombucha.
Kombucha brewing under the food and drug administration model food code: Risk analysis and processing guidance. Nummer(2013). J Environ Health 76(4):8-11.