Hi Charles - I hope I'm doing this right and it's the right forum...
I've had a discussion with some friends about the pH of tea. I say it's acidic... others say alkaline. (By "tea" I mean just tea itself, camellia sinensis - not herbs, fruit additives, etc.)
I googled around the web and as far as I can tell the pH range varies with the tea and brewing parameters, but all are in the acidic range, below 7 (<7). It seems tea is commonly used to acidify soil for plants in gardening. Also there are extensive tests on the effects of tea on dental enamel -- which tends to be viewed as a better beverage than even more acidic drinks which might contain citric acid and sugar, but the tea still has an acidic pH level. Also, I'm under the impression that the acidic quality of tea causes it to be antimicrobial.
Anyway - I thought maybe you'd have an answer. I figured Adagio has all kinds of lab equipment and regularly tests this sort of thing