What Makes a Tea?
All
tea is produced from the Camellia
sinensis plant, a shrub native to China and India. The different types of tea vary based on the
region or country where it is grown, which parts of the Camelia sinensis are used and how they are treated before
brewing. Any brewed drink that doesn’t
include part of the Cameliia sinensis
plant is not tea; it is a “tisane.”
Types of Tea
There
are five different recognized types of tea:
- Green teas,
- White teas,
- Oolongs (called Blue teas in China),
- Black teas (called Red teas in Asia), and
- Post-fermented teas (called Dark teas in Asia).[1, 2]
The different
types of tea are distinguished by the degree to which the tea leaves and/or
buds are “fermented” or oxidized. Tea
does not undergo true chemical fermentation, although that term is used in the
tea industry to describe the process.
Instead, tea properly undergoes oxidation, the process by which atoms
lose electrons, resulting in chemical changes.[2] The oxidation process causes changes to the
flavor, aroma and overall appearance of the tea, resulting in different types
of brews.
Green Tea
“Green tea” has undergone the least
amount of oxidation/fermentation of all of the tea varieties. The leaf is briefly wilted to lose water,
then heated before it completely dries and before any enzyme activity can take
place. The heating can be done in a
variety of ways, including sun-drying, steaming, baking and pan-roasting. Sub-varieties of green tea are based on the
shape of the leaves and the method of drying.[2, 3]
White Teas
The category of tea is lightly
oxidized/fermented before being baked dry.
It is usually made from young leaves and new growth buds. Flavors can vary based on the size of the leaf
used.[2]
Oolong Teas
To create an oolong tea, the young Camellia sinensis leaf is grown to a
slightly larger size before picking. The
leaves are then wilted in the sun for a short period of time before being “bruised,”
usually by being placed into baskets and shaken. The leaves are then exposed to and allowed to
oxidize for a very brief time, in some cases less than 2 hours, before being
baked dry.[4]
Black Teas
The most commonly found type of tea,
black teas are fully oxidized or fermented.
After being picked and dried, black tea leaves are rolled, either by
hand or by machine, causing the leaves to undergo chemical processes. The leaves are allowed to oxidize until they
turn a dark reddish-brown, then fired.
If the tea is intended to be used in tea bags, after firing it is passed
through another machine to be cut into finer and smaller pieces.[5] The taste of black tea can vary based on the
place where plant is grown, the specific variety of plant and the exact methodology
of the tea-maker.
Post-Fermented
Teas
Post-fermented tea leaves have been
subjected to a microorganism-induced fermentation process, rather than the
enzyme oxidation process used for other teas.[1] Plucked tea leaves are briefly withered
and/or sun-baked, twisted, then subjected to microbe activities before they are
dried.[3] The resulting infusion is much
darker than other teas. Post-fermented
teas are sometimes known as “puer” teas.
Tisanes
Things
that are often called tea, but are actually tisanes, include:
- Rooibos or “Red Tea” or “Bush Tea”: Rooibos “tea” is made from the Aspalathus linearis plant, a member of the legume family, grown primarily in South Africa.
- Mate “teas” are brewed from the leaves and twigs of the yerba mate (Ilex paraguariensis) plant, a member of the holly family from South America. Yerba mate infusions are popular with coffee drinkers because they taste more like coffee than tea.
- Herbal “teas” are the most commonly found “tisanes.” They can be made from a vast variety of herbs, roots, bark, seeds, fruits, etc.
[1]
http://teaguardian.com/what-is-tea/tea-classification-1.html#.UqNllfRDuSp
[2] http://ratetea.com/topic/oxidation-of-tea/57/
[3] http://teaguardian.com/what-is-tea/green-tea-nature.html#.UqNnS_RDuSo,
[3]
http://teaguardian.com/what-is-tea/dark-tea-nature.html#.UqNq_fRDuSo
[4] http://www.teamuse.com/article_060601.html
[5] http://www.teamuse.com/article_060501.html
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