When producing the kombucha drink, the sugar that
is added to the tea ferments during the process and it produces alcohol. The amount of alcohol depends at the same time on the
temperature and also on the amount of sugar present in the fermentation jar.
With a minimum of 50 grams of sugar, the kombucha drink draws about 0.1% alcohol after 14 days, and about 0.3% after 21 days. If larger amounts of sugar are used (for e.g. 200 grams) the drink will reach 2% alcohol after 14 days, but its taste will be very sour and almost undrinkable. An ideal amount of sugar and a fermentation time of six to ten days produces a very low percentage of alcohol (Source: "Kombucha, The Miraculous Fungus", Harald W. Tietze, Amrita Editions, 2010). The drink can therefore be safely consumed by children and adolescents.
For comparison cider, obtained by the fermentation of apple juice, contains between 2% and 8% alcohol (source: http://fr.wikipedia.org/wiki/Cidre).