To answer the question “ What is green tea ”, we have to go back to the very start….
To tea in general that is!
What Makes Tea, TEA?
Tea is the popular name for the Camellia sinensis plant or green tea plant. Well, to be exact, it’s the name for the leaves of this plants.
You can’t make tea from any other plant.
Well, you can boil water with leaves from a plant or even fruit, herbs or flowers but officially you can’t call this mixture tea then.
These so-called “herbal teas” are infusions or tisanes that do not contain Camellia sinensis. A well-known example is the South African rooibos.
The Three Main Types of Tea
The real deal comes in three basic forms determined by the processing it has undergone:
- Black tea
- Green tea
- Oolong tea
Most tea produced and consumed worldwide is black tea, which makes up around 76 to 78% of all tea. Green tea represents around 20 to 22% of the tea produced worldwide and Oolong tea represents only about 2%.
That’s why you probably also remember
having a cup of black tea as a young boy or girl and
the terms Earl Grey, Ceylon or Darjeeling ring a bell!
What Causes the Variety in Tea?
The difference between the three main types of tea lies in the manufacturing processes, altering the chemical composition and properties of each of these teas.
The first step in the production of black tea is allowing tea leaves to wither or dry. During this first step the leaves’ moisture content is reduced and they lose nearly half of their original weight.
The second step is to roll and crush the withered leaves to remove all moisture, initiating fermentation. Fermentation is the oxidation process where the tea leaves break down certain unwanted chemicals and modify others to develop the dark color and the characteristic tea flavor.
Oolong tea is made in the same way as black tea, except that shortly after rolling the leaves they are fired to stop the oxidation process and dry the leaves. As a result, oolong tea is about half as fermented as black tea.
Yes, this is all nice, but what is green tea?
Well, contrary to black tea and oolong tea, green tea is made from freshly harvested leaves rapidly steamed or pan-fried before allowing them to dry. As a result, no fermentation takes place at all.
Important Green Tea Ingredients
What part exactly oxidizes? Well, that’s the substance we find in fresh tea leaves called polyphenols, a group of strong antioxidants. Antioxidants are our army of helpers to protect us against free radicals inside our body; these radicals are constantly trying to destroy our body! We don’t want that now do we?
One category of polyphenols are flavonoids (found in fruits and vegetables but also in red wine and chocolate). Within this category you can find the group of catechins of which the most important is EGCG.
This catechin is subject in many scientific studies as it’s supposed to be an inhibitor of certain types of cancer and contributes to many other health benefits.
Other Types of Tea
Looking closer at the types of tea you can say there are three additional types of tea. These are:
- White tea (withered and non-fermented)
- Yellow tea (non-withered and non-fermented, allowed to yellow)
- Post-fermented tea (green tea allowed to ferment, such as pu-her tea)
Green tea is very similar to the fresh leaves only the plucking makes it slightly different. Most of its beneficial effects are maintained though, if it’s organically grown that is.
So, what is green tea?
It’s the least processed type of tea
with the healthiest ingredients!
Sources “what is green tea”
Brannon C. Green Tea: new benefits from an old favorite? Nutrition Dimension, 2009.
McKay DL and Blumberg JB. The role of tea in human health: an update. Journal of the American College of Nutrition 21(1):1-13, 2002.
Mukhtar H and Ahmad N. Tea polyphenols: prevention of cancer and optimizing health. American Journal of Clinical Nutrition 71(suppl.): 1698S-1702S, 2000.