liu'an and liubao production

Summarized some information from a couple of AoT articles about liu'an in this Teachat thread:
http://www.teachat.com/viewtopic.php?t=16991

Thought I'd post it here, for everyone's edification, as well as to spark some discussion. I'd love to hear more information about the liubao production process.

They [liu'an and liubao] are made in different areas, and I believe, made with different raw materials and different production methods. However, they are fairly similar; people with a lot of experience can probably usually tell them apart, though I've heard that, while liu'an had a gap in production, liubao in liu'an size baskets was sometimes sold as liu'an. Both can have some medicinal / herbal tastes, and both are said to aid in digestion and help with constipation. From what I can gather, liu'an basket tea may be considered "cooling" [information based on article mentioned below], however, whereas liubao may be "warming" [numerous internet sources, but nothing super reliable].

The liu'an that I've experienced is usually in a 500g basket. Liubao baskets are often, but not always, much, much larger (up to 20 kilos for a single basket). Liubao is also more recently sometimes pressed into cakes which resemble pu'er cakes.

According to the article described here in issue 5 of Art of Tea [pp10-15], liu'an has two production techniques. Both start with kill-green, like green tea or pu'er. For the first method (I guess you would say more like sheng pu'er), the tea is put into bamboo leaves and then baskets, and roasted in the basket to dry them. For the second method, the tea leaves are withered in the sun, kill-greened, and then rested for about half a year. Then, water is added, and the tea is wrapped / packed in the bamboo leaves and basket. The tea "ferments" like this, and then the baskets are dried.

The article also says that the tea is made in Qimen (祁门) in the south part of Anhui；same Qimen as Qimen (Keemun) red tea), but doesn't have a conclusive explanation as to why it's not produced in Liu'an (六安), which is in the west. My understanding from the article is that it likely does not use the same type of tea leaf as liuan guapian, and that further, that liu'an basket tea has been produced for a longer time than liuan guapian.

The inside is bamboo leaf, not bamboo bark (of the sort used for pu'er tongs). It's customary to brew a small piece of the bamboo leaf along with the tea. In my experience, the "raw" variety can be pretty bitter when young.

There is also liuan guapian, which is a famous green tea, also from Anhui.

Liubao is made in Guangxi. I don't know much about the manufacturing process; I believe it is similar in a lot of ways to liu'an.  I don't know how accurate this description is, but this article claims that liubao is partially oxidized after kill-green. I can believe that it's partly oxidized, but not sure whether bruising will work after kill-green.
See also:
http://www.teachat.com/viewtopic.php?t=2675
http://teadrunk.org/post/141/#p141

Two other articles in the same issue [pp 4-9, pp 16-26] are a bit more specific on the dates where there was a gap in production of Liu'an basket tea. The gap seems to have been from about 1943, until demand from HK and SE Asia caused production to be re-started in the mid-80s. So, be skeptical of any Liu'an that's supposed to have been produced in between those times.

This other article also mentions a couple of other interesting teas sold by HK tea merchants which might be confused with Liu'an basket tea [let me know if I've got any of the information, characters, or translations wrong]:

"Nice [read fragrant] Liu-an" (香六安): The article says that this is loose-leaf pu'er [so, not liu'an at all] blended with Aglaia odorata (米仔兰, I believe) flowers, and, in some cases, black or green tea leaves [I don't know whether they mean "red" or "black" in Chinese terms, but assume red]. Cloud's article [pp 16-26] suggests that this actually originated from a practice used to improve the taste of Liu'an green tea that had to travel a great distance.

Liu-an Stems (六安骨): [骨 is literally "bone", I believe, but correct me if I'm wrong] Apparently oolong stems, which are then roasted. No relation to actual liu'an teas. These are not on the market anymore for the most part, because oolongs now have the stems removed before being sent to HK, rather than being shipped there with the stems on, to have them removed before sale.

Also some mention of these last two at
http://www.discuss.com.hk/viewthread.php?tid=12878484 [in Chinese only]