Dark Tea or Pu-Erh

This type of tea, also known as Pu Erh or dark tea, is produced using a steaming process that causes non-enzymatic fermentation, different from that of black teas.

Before being rolled, the leaves undergo a specific type of roasting which kills most of their enzymes. This is done in iron pans heated to 535°F-610°F / 280°C-320°C into which the leaves are placed and then covered with straw. The straw stops the steam from escaping and allows the leaves to be steam cooked. This is essential as the leaves are old and therefore lacking in moisture. During this operation, the caffeine content of the leaves is reduced.

After a first rolling, the leaves are arranged in piles of about 3.3 ft / 1m high and covered with a damp cloth that will keep the humidity level at 85%. This is known as the sweating process. It lasts about 24 hours and can be repeated several times. The size of the piles and the duration of the sweating process have important consequences for the tea produced, with the aroma being more - or less - enhanced.

Dark teas can often be found in the form of compressed briquettes or bird's nests. They are also the only teas that improve with age and for which age can sometimes carry enormous weight when selling at auction.