I've thought of using teas to flavor my beer before. But one thing lead me not to do it. Tannins. Tea ussually contains a lot of tannins.
I did make a mead out of Rooibos tea once, it turned out pretty good since Rooibos is a low tannin tea, just like any red tea. Black teas have the highest tannin levels of teas, except for certain herbal teas.
I would of used peach flavoring
in the finished beer and used freshly grated small ginger root in the secondary.
Do let us know if the teabrew turns out.