There are six categories of tea: black, oolong, green, yellow, white, and dark tea. Dark tea is an aged tea from China which has gone through a secondary fermentation process. Puer is a sub-category of dark tea.
What does it taste like?
The aroma of dark tea may be slightly earthy, but this typically does not carry over to the flavor. Dark tea can be light to full bodied. It is smooth, with a noticeable sweet, floral flavor.
Where does it come from?
The manufacture of dark tea dates back to the 1500s. Most dark teas come from three counties (Anhua, Yiqang, and Linxing) in Hunan Province of China.
How is it made?
Two processing steps distinguish dark tea: pile fermenting (oxidizing) and pine fire drying. Dark tea undergoes an aging process in which bacteria reacts with the leaves, changing the chemistry, flavor, aroma, and appearance of the leaf. The specifics of aging are closely guarded trade secrets.
Dark tea vs. Puer tea
Dark tea is not the same as puer tea. Puer is only made in Yunnan province and is known for its earthy aroma and flavor. Dark tea is from the Hunan province and tends to be lighter, sweeter, and less "in your face" than puer. While both teas are aged, dark tea is not aged for extended periods of time, as is puer. Dark tea is meant to be consumed at the time of purchase. Both puer and dark tea are probiotic, although the specifics differ.
Preparing Dark Tea
Dark tea is often made with a little more leaf per cup than other teas. Instead of using a rounded teaspoon(3 grams), use a heaping teaspoon (5 grams) per 8 oz. cup of water. Steep in 208-212 degree water for 4-6 minutes. The leaves may be re-steeped for multiple infusions. Some people rinse the leaves with hot water for a few seconds before steeping and many people let dark tea cool considerably before drinking.
* Dark tea was one of the first teas to travel the ancient trading routes of the Tea Road and the Silk Road into eastern Russia. Dark tea is known as a "tea of the people."