Hi Michael,

roasting should stop oxidation, and lead to taste differences. *Exactly*
what they are eludes me sometimes. That's why I too need a bit of
clarification.

Me too. I have problems with English.
So far, I thought the term "roast" for tea was reserved to the roasting done
to certain teas (mostly green or oolong) after the whole first process is
done, after they are completely oxided/stopped/dried/fermented. The
operation to stop the oxidation is called anything but roasting (pan-firing,
steaming, heating, cooking....).
My understanding is the packages allude to that second-process roasting.

Not all oolongs are roasted. You can roast your tea yourself at home (it's a
good way to recycle greens that are getting a bit old) to see the effect.

It appears
to me that if a tea is more heavily roasted, but not very highly oxidized,
it will appear quite dark as dry leaf, but become much greener in the
water.

No, in my experience, they appear very dark brown/orange in the water, they
get closer to coffee. In taste too.

About the health point of view. I don't have the reference here, but
roasting tea make it lose some exciting substances like cafeine/theine, so
roasted teas can be better for children or to drink in the evening if you
fear to have problems to sleep. They also have properties for Chinese
medicine, and are given to people that are sick and recovering. But they
lose vitamins or I don't remember what.

Kuri