Notes on green tea cake
This compressed tea is definitely of the "green," "raw," or "sheng" type, versus compressed tea that has undergone a secondary fermentation process (cooked or shou pu'er).
It might not actually be pu'er depending on origin; it is from China but maybe not from Yunan province. It is a hei cha, a compressed tea, but seemingly not very fermented by aging as the type implies.
The package label is only in Chinese and the vendor spoke only Thai so it was only sold as green tea ("cha keo"). With my limited Thai I could've still asked about the year produced but didn't.
The tea tastes a lot like a fresh green tea.
Normal profile of green tea varies with an unusual mustiness, but just a little, and not in a bad sense. It doesn't taste off, just unusual as fresh tea goes, perhaps not so unusual for compressed tea. There is relatively little astringency to the tea, and I would have expected some. The tea brews to a gold color, as the appearance suggests apparently not fermented by aging.
Other flavors are slightly vegetal, towards grassy, but generally nonspecific. There is one subtle underlying taste element like part of a clove flavor, complex, and nice, but not really spicy like clove.
Partial flavor aside:
The taste was cleaner after first infusion, less musty, but otherwise didn't change as far as adding or dropping taste components goes.
Tasting it raised more questions about pu'er standard flavors, aging, etc. I've tried some puers but definitely can't write the beginner's guide on all that. Tea flavors are said to change and improve over time, but I'm not really clear on how, so I'll have to do more reading and tasting and come back to that.
Summary of this tea: interesting
I liked it, even though there was really nothing noteworthy about it; it was just a basic green tea. It was a smaller and inexpensive cake (100 grams--I think--for around $6), and I won't keep it around to see how it ages, I'll just drink it. Given it didn't cost that much more than a Starbucks coffee I should buy another cake and stash it.
I saw a discussion post once comparing the appearance of a compressed tea to marijuana, and this did look a little like brick weed (not that I've ever seen that in person). Then again any leaf-type plant or the like might look similar when pressed into a cake.