Green Tea - varieties & preparation methods
What is green tea?
... and how is it different from black tea?
Green and black tea actually come from the same plant: Camellia sinensis. The difference is in the way they are processed.
- Green tea is heated (either by steam in Japan, or pan-frying in China) that destroys the naturally-occurring oxidizing enzymes in the leaf.
- Black tea is first rolled or cut, allowing those enzymes in the tea leaf to be released, and oxidize the many phytochemicals in the leaf.
The oxidation process changes the chemical character of the tea, so the flavor, color and chemical composition change. Oxidation reduces EGCG (a healthful antioxidant) and raises the level of caffeine, which is why green tea typically has about half the caffeine of black tea.
Note that herbal teas (or tisanes), such as chamomile, rooibos, and mint, are not from the Camellia sinensis plant. Yerba mate, an Argentinian tea not made from Camellia sinensis, has caffeine, but almost all other herbal teas are caffeine-free.
There are 3 major green tea producing regions:
China: Known for pan-frying tea leaves to prevent oxidation/fermentation, Chinese green teas have a characteristic rich smokiness with considerable depth of flavor. The island nation of Taiwan is well-known for its Oolongs (Wu lung), which are semi-oxidized teas, somewhere between green and black teas in flavor.
Japan: Using steam to halt the oxidation process, Japanese green teas are greener, with a more vegetal, grassy flavor. In my experience, they are much more sensitive to high water temperatures and oversteeping, so in order to enjoy Japanese green tea's natural sweetness, remember "less is more".
India: India's Assam, Darjeeling and Ceylon (Sri Lanka still part of the Indian cultural tradition) are traditionally known for black teas, although their green teas are worth trying, depending on your taste. Indian green tea has a sharper, peppery note, not quite as sweet as Chinese and Japanese green teas.
Popular types of green tea
Here are the types of green tea that I've tried:
Dragonwell (Lung Ching, in Chinese): a vibrantly green, flat-pressed leaf that yields a bright green, very sweet drink. It should *not* be prepared with water that is boiling hot, and should not be steeped for more than about 3 minutes.
Gyokuro: this is the finest Japanese green tea, and due to its different process from Chinese green tea (the leaf is steamed, instead of pan fried like Chinese green tea), it has a more vegetal, grassy flavor. Gyokuro is processed much like its more popular cousin, Sencha, except it is kept under the shade for the last couple of weeks before picking in order to build higher levels of chlorophyll in the leaf. Like Dragonwell, it should be prepared with water that's about 180F (not boiling), and shouldn't be steeped too long.
Gunpowder: This tea, while supposedly not the absolute highest quality (you can buy a decent-sized box for about $5 in Asian supermarkets), holds a special place in my heart since it was the first green tea that I really took to. The tea is rolled into tightly-wrapped balls, and when placed in hot water, they unfurl in a process the Chinese call "the agony of the tea". It makes for a nice visual effect, and the tea has a great smoky flavor.
Tung Ting: This is technically an oolong tea from Taiwan, although its process involves relatively little oxidation, so it tastes more like a green than other oolongs. This is one of my favorites for its vaguely peach-like flavor, and its tolerance for hot water. Even when I've oversteeped it, it has never turned mouth-puckering.
Sencha: This is the most popular type of green tea among the Japanese, and constitutes about 80% of Japanese domestic tea production. It's the type of green tea that you're served in sushi restaurants--a light green color, with a faint grassy, wheaty flavor. Much like Gyokuro, it should be steeped in water well below boiling (180F is ideal).
Matcha: This is a powder made from grinding gyokuro leaves. It's traditionally been used in Japanese tea ceremonies--the matcha is whipped into the hot water with a bamboo whisk until it has a pale green foam at the surface. Since the resulting liquid is not tasty (it's really bitter), matcha nowadays is much more commonly used in green tea flavored foods, including ice cream, noodles, and pastries.
The caffeine content of your cup of tea is highly dependent on the type of tea, how long it's been steeped, and naturally, the concentration of tea (how much tea per quantity of water). That said, if we look at type of tea only, here's what we find for a typical 6 oz cup:
- Green tea or white tea: 15 mg
- Oolong tea: 25 mg
- Black tea: 40 mg
For reference, a cup of drip coffee has about 80 mg per cup, and a typical 2 oz shot of espresso has about 90 mg. A 12 oz can of coke has about 45 mg of caffeine, and Red Bull? 80 oz in one of those little silver cans.
TIP: If you want to reduce the caffeine content of your tea....
Caffeine is highly soluble in hot water, while the complex of oils and polyphenols that give tea its characteristic flavor take a bit longer to come out in the tea. So, if you want to take out a substantial portion of tea's caffeine without impacting the flavor too much, steep your tea for about 20 seconds in the hot water, flush out that water, and then begin steeping again. The first "rinse" of water will have taken out much of the caffeine but relatively little of the flavor.