Is Oolong Tea Black Tea?
Black tea was the first type of tea that was introduced to the West hundreds of years ago. The Dutchman Jan Huygen van Linschoten was the first who successfully shipped tea to Portugal. In contrast, oolong tea is a relatively new tea that became popular in the recent years. It's therefore not surprising that many people don't really know the distinguish black and oolong tea. To understand this better, you need to first understand the difference in processing.
Oolong Tea versus Black Tea Production
A lot of people believe that oolong tea is a type of black tea. This isn't true. Like all teas, oolong is also made from the Camellia Sinenses tea plant. However, each tea type is processed in a different way. The processing methods used for black teas result in fully oxidised leaves. On the other hand, oolong teas are only partially oxidised. They're also known as 'semi oxidised' teas. The former term is more correct, because different oolongs can have different levels of oxidation. Take for example a Tie Guan Yin, which is very lightly oxidised, and thus maintaining a green colour. Therefore, it's not strange that many people wrongly think that Tieguanyin is a green tea.
Other oolong teas such as Dan Cong and Da Hong Pao have a darker colour. They're dark oolong teas that are sometimes also called black oolong teas. These teas have oxidation levels that are closer to black tea, though they still belong to the oolong category.
From a raw material point of view, black teas that consist of small buds are generally considered more premium. Teas like Lapsang Souchong or Keemun all consists of small leaves or buds (if they're good). Black teas even more expensive, if there's a lot of golden buds, which is the case for teas like Yunnan Gold or Jin Jun Mei.
In contrast, oolong teas are less about small buds and leaves. In fact, they often consists of larger leaves, which are more suitable for the intense processing. With oolongs, the edges of the leaves are brushed when the teas are rolled, resulting in complex aromas. This is especially the case with Tie Guan Yin.
While sometimes black and oolong teas have similar appearances at first, the taste is completely different. Black teas often have honey, caramel or smokey notes. In contrast, light oolongs often taste more like green tea with flowery notes. Dark oolongs have very distinguished mineral rock flavours that are significantly different from the taste of black tea.
To sum up, black tea and oolong teas are really different tea classes. There differences in processing methods result in different levels of oxidation. Good black teas often use small leaves, while this matters less for oolong tea. The difference in processing and raw material selection result in different flavours.
While we've attempted to try our best to explain the differences, we highly recommend you to experience the difference yourself. Several years ago, cheap oolong was at first introduced as a weight loss tea in the West. Today, there's a wide offering of excellent artisan oolongs in different online and local stores.