[nostromo]

I'm surprised 6-13 year olds are drinking several cups of tea a day in Japan. Isn't that a fair amount of caffeine for a kid?

[hinkley]

Green tea is about on a par with Mountain Dew for caffeine per ounce, but closer to Coke for caffeine per serving.

The fermentation process for black tea is longer than green tea, and more of the caffeine becomes solluble, but it's still less that coffee.

[hinkley]

correction: it's not fermentation, it's an enzymatic process referred to as "oxydation", as I was reminded while fact-checking for another reply.

There is fermented tea, but the tea you drink is probably not.

[Mikeb85]

Nah. Tea has a small amount of the caffeine as coffee and coffee is very safe (takes like 20 cups to OD).