Originally from Ancient Asia, kombucha is now a modern beverage. While many cite a variety of health claims, the clinical science to back those claims is lacking. Excess consumption can lead to chemical acidosis.
Kombucha is a fizzy, cider-like beverage made from fermented sweet tea. A starter culture, called SCOBY (Symbiotic Colony of Bacteria and Yeast), is the key to fermentation and looks like a jelly pancake in the kombucha liquid. The SCOBY is affected by climate, geography, culture, and wild microorganisms making each batch of kombucha unique.
When making kombucha at home, care must be taken to use safe, hygienic practices to keep a clean environment and minimize contamination. In general, kombucha is considered non-alcoholic. But if the alcohol level exceeds 0.5 percent alcohol by volume, then the sugar or yeast concentration is too high or it was fermented too long. In general, home fermentation is around three days.
Pregnant women or those with immune-compromised health conditions should not consume kombucha. Improperly made kombucha can contain pathogens or have unsafe concentrations of organic acids.
Sources: https://bit.ly/2uW7gTF; Food Technology, March 2019; Food Protection Trends, Sept/Oct 2018