Did you know that green tea is black tea? They are from the same tea plant but they are prepared differently but green tea has very little of the same caffeine effect that black tea has. When you drink green tea you absorb the caffeine slower because of certain properties that green tea has... green tea also has other properites that calm you down.... so you don't feel the caffeine effects as much as you do with black tea but, believe it or not green and black tea have the same original amount of caffeine.... I have read in more than one place that the kombucha mushroom prefers black tea; but, you can use green tea if your stomach is sensitive or if you are making the tea for a person who is sensitive, it is then recommended that you use green tea. You can use a tea called oolong which is in between black and green tea in terms of the effects of caffeine, less than black tea but more than green tea.

Kombucha during its fermentation will digest as much as half of the caffeine from the tea... I now think it is good to mix you teas and use differnet ones for fermenting or mixing them all so the kombucha culture can get the different good qualities from each of the black,green and oolong teas... if you would like to use teas that are not from the tea plant... be very careful... some herbal or roots plants can be antimicrobal or have volatile oils that can hurt your culture... No Earl Grey etc... and don't use more than 15 percent of say oh... yerba mate or rooibos tea and make the rest of the brew from 85 percent of the original tea plant