I had a discussion with WhiteTeaWizard and a couple of other board members regarding jasmine tea recently. Specifically, the fact that Adagio classifies its jasmine teas as oolongs, while many other companies classify their jasmine teas as greens.
As it turns out, the extra step of adding jasmine to tea partially oxidizes it. Basically, the jasmine flowers are combined with the tea before firing and left with the tea for some time. This allows the tea to oxidize slightly, resulting in a lightly-oxidized tea. So it is no longer really a "green" tea. Instead, it is a scented pouchong tea.
Pouchong is often referred to as "chinese green." The nickname may be the reason why so many companies classify it as a green tea. However, it is not technically a green tea, because it is partially oxidized.
On the other hand, pouchong is not really an oolong, either. Pouchongs are about 10-20% oxidized, whereas oolongs are 30-80% oxidized.
-------- TEA TYPES --------
Really, the source of confusion seems to be confusion over the types of tea in general.
There are only three major sub-types that everyone can agree on:
But confusion already exists at this point in classification. Some people refer to these categories by other names. For example, non-oxidized teas may be called "non-fermented" or "GREEN
". And the other two categories have the exact same problem (with partially-oxidized teas being called oolong, and completely oxidized teas being called black or red). No wonder there is so much confusion!
After that, each of the three major types is usually further divided into sub-types.
• Non-oxidized is divided into three types: green, yellow, and white
• Partially-oxidized is divided into two types: light or pouchong (lightly oxidized) and heavy or oolong (heavily oxidized). - * See Note
• Fully-oxidized is divided into three types: black/red, green pu-erh, and black/cooked pu-erh.
What differentiates all of these sub-types is the processing methods involved. All of these teas are first picked, then sorted/screened. After that, any number of things may occur to differentiate one tea from another.
For non-oxidized teas:
• White tea is withered, then dried/baked.
• Yellow tea is steamed, smothered (covered with cloth), then rolled, then dried/baked.
• Green tea is steamed or pan fired, then rolled, then dried/baked.
For partially-oxidized teas:
• Pouchong tea is withered/steamed, shaken or rolled, spread out for an extremely short time (to 10-20% oxidation), and then fried or dried.
• Oolong tea is withered, shaken or rolled, spread out for a short time (to 30-80% oxidation), and then fried or dried.
For fully-oxidized teas:
• Black tea is withered, rolled, spread out under high humidity until they have fully oxidized, and then fired.
• Green pu-erh tea is heated, rolled (sometimes), withered until 90% moisture has been removed, sorted by grade, steamed & compressed, and then stored in a dry environment to encourage slow oxidation (this is why green, or uncooked, pu-erhs benefit from aging).
• Black pu-erh tea is heated, rolled (sometimes), withered until 90% moisture has been removed, sorted by grade, oxidized for anywhere from several days to a month, and then either stored in cloth bags (loose leaf) or steamed and compressed.
-------- CLASSIFICATION OF TEAS BY TEA SHOPS --------
Many tea companies carry pouchong, but do not have a pouchong category. Therefore, they feel the need to either categorize it as green or oolong. It appears that many companies choose green, while Adagio chooses oolong. Neither is really correct, however. Unless you only recognize three types of tea. In which case, you can't have a white category (white would be classified as a "green" or "non-oxidized" tea).
The same problem, incidentally, occurs with pu-erh and yellow teas: many tea companies don't have a category for them, so they choose to place them (incorrectly) into a different category.
Perhaps the answer to this dillemma, rather than incorrectly classifying teas, is to create a category called "miscellaneous" and place all pouchong, yellow, and pu-erh teas into that category.
-------- NOTE AND SOURCES --------
Some go a step farther in dividing partially-oxidized teas to include a medium (medium oxidized) category. In this case, the light category contains pouchong, the medium category contains most oolongs, and the heavy category contains champagne oolongs and ti kuan yin.
Hope that helps clarify things a little bit. Sorry for the length.