Puerh cakes can be found in many sizes and shapes, especially now that a lot of U.S. based vendors are doing custom pressings. Tuocha, puerh balls, and smaller 100g cakes are a great option for tea drinkers that just getting started. Traditionally though, bings weigh an oddly precise 357 grams. I've often wondered what the reasons are for that and this post sets out to find the answer.
First, we should keep in mind that the metric system is a fairly recent invention (in relation to how long people have been drinking tea). Production of puerh cakes dates back to the Qing Dynasty. For most of the world's history, units of measure rarely crossed borders. Even today tea in China is more likely to be measured in liang or jin rather than grams or kilograms.
A single 357g cake is the equivalent of 7 liang. For storage and transport, the tea is packed into tongs. Each tong is a stack of 7 cakes wrapped together in bamboo. Tongs are referred to as Qi Zi Bing and weight 5 jin, or just a hair under 2.5kg. I've read in a few places that 7 is considered to be a lucky number in Chinese numerology so that may have played a role as well.
Tea was originally pressed into bings because compressed tea was easier to transport via horseback than loose leaf. The Ancient Tea Horse Road, or Cha Ma Gu Dao, was a trade route that first emerged during the Tang Dynasty. Teams of people, mules, and horses traveled precarious mountain passes in order to trade tea with Tibet. 12 tongs were packed into a large basket, totaling approximately 30kg. Each horse or donkey would be able to carry one basket on each side. It is believed that being carried on long routes through humid environments (and next to the body heat of the donkeys) may have caused natural fermentation to occur.
|Tea Horse Road memorial statue - Chengdu, China|
A number of readers have noticed the puerh-ish lean here on the blog recently. Most of that has to do with my own changing tastes and tea experiences. Please let me know in the comments if there are questions you have about puerh (or any other type of tea) like this one! I'll do my best to answer or at least find someone else who can.
Tea Horse Road statue image by Daderot (Own work) [CC0], via Wikimedia Commons