>All I know is, Hunan, Yunnnan and Sichuan all make various forms of tea
>bricks. So I guess any of them would be suitable for making buttered
>tea.

I think they usually just use black tea to make their "su you cha", but
it's mostly milk/butter. Someone from Tibet once told me that they
originally drank it without tea leaves (long while ago), and they only
started adding tea to improve the flavor. It's really freezing up
there, and they drink it for nutrition. It's one of those things they
use for survival.

I guess it wasn't supposed to become popular.