Popping an old thread because I've been experimenting with oxydizing black current leaves, and I'm getting fairly satisfying results in terms of a tannic tea substitute. The fresh leaves have a very nice currant taste, but I've found that they lose most of their interest when just dehydrated. So I figured I'd experiment with traditional tea making techniques.
Oxydized black current leaf tea is apparently a staple in Russia, and if I recall well, I got the initial idea from a Google translated Russian website. I've combined that with my experience making hand-rolled green tea this summer, and I'm still working on perfecting my recipe. (I've had quite a few batches turn out tasteless or moldy before my most recent one)
But the gist of it is that I'm going to roll and bruise the fresh leaves in my hands for a fairly long time in order to get the flavors to develop.
When you do it the correct japanese way with tea leaves, it's about 45 minutes of rolling over a warmed pot, so you dry it and roll it at the same time (see photo). But this produces green tea, not black tea like I wanted.
For black current tea at home, I do about ten minutes of rolling because there are limits to my dedication
I then packed them tightly in a glass jar and waited three days. Every day, I mix it up, roll a bit and pack again, checking for mold and making sure it oxydizes evently. When the leaves turn dark, I dehydrate them.
The result is a fairly tannic drink, with more depth than the fresh leaves and a lot more taste than without the process. It needs to steep longer than regular tea though, so I recommend a tea cozy.
(Next summer, I hope to find a good fireweed patch to try the same process with fireweed).
)