Big Leaf (大葉茶, Dà Yè Chá, "Big Leaf Tea") is essentially a Sheng Pu'er made from the long, older leaves of large tea trees. Too large to process in the conventional sense, these leaves are tied into bundles, similar to Broom Tea. Each bundle consists of 12 leaves, and five bundles are tied together to form a sheaf. Four sheaves together makes up a tong, which is wrapped in bamboo leaf.
The tea sourced for these big leaf bundles is necessarily from large, usually older, Pu'er tea trees. These are not the same tender buds and leaves that are used for normal Pu'er, but may be considered a giant example of Huáng Piàn, the fully-opened leaves enjoyed by farmers. These lower leaves have been on the tree sometimes for several seasons, allowing them to grow to an immense size.
There are several ways to prepare these leaves. The most suitable for gong fu cha is to break them up into pieces roughly the size of normal Pu'er leaves and to steep them in a gaiwan or teapot at full temperature. They may also be steeped one leaf at a time by placing the whole leaf in a tall glass or mug and pouring hot water over it. As the leaf softens, it can be squished down into the vessel. Lastly, the leaves can be boiled in a pot.
Using any method, these giant leaves yield a surprisingly clear, bright, and sweet liquor with almost no bitterness. The tea, being from old trees, has a deep, grounding Qi. The leaves are large and brittle, and some breakage is to be expected - at the tea house we like to use the most intact leaves whole, then use the broken pieces in a tea pot after all the whole leaves are used up.