Green and Black Teas for Health
Green Teas
Differentiation between green and black teas occurs during the processing of leaves. To make green teas leaves are processed to minimize oxidation and prevent fermentation of oils in the tea leaves. Immediately upon picking, leaves are steamed at about 200 degrees farenheit for 30-45 seconds to deactivate the polyphenol oxidase and other enzymes that cause oxidation and fermentation. The leaves are then rolled and dried to stabilize the tea's natural oils.
Bancha is the lowest grade. Bancha produces a brew that is harsh with a bitter edge and very little of the fragrance that gives good green teas their charm. The cost of bancha is a small fraction of choicer grades, making it economical to provide free of charge in working-class restaurants.
Sencha is made exclusively with the top two or three leaves closest to the bud. It's the grade ordinarily served with meals in Japanese homes and fine restaurants. It accounts for the vast majority of green teas found in retail markets. Sencha itself is divided into high, medium and low grades, depending on precisely which leaves are used. In the U.S. a 100 gram (about 0.22 pounds) package of sencha sells for around $3-$12.
Gyokuro is the sweet, fragrant whole-leaf premium tea used mostly for giftgiving or to impress special guests. This grade is made exclusively with exceptionally tender buds and small top leaves that were carefully shaded from the opening of the bud. Premium-grade green tea doesn't turn bitter no matter how long the leaves are left to steep. A 100 gram package sells for upwards of $40 and some go as high as $150.
Macha is the powdered tea used mainly in tea ceremonies and for some types of fine cooking. It is usually made from high-grade sencha but is more expensive due to the special care used in its preparation.
Black Teas
Unlike green tea, black tea is processed to maximize oxidation and fermentation of oils. Immediately upon picking, the leaves are allowed to wither in direct sunlight for 12-16 hours, then rolled to break the membrances and allow oils to seep to the surface. The leaves are spread out in four-inch deep layers for many days until the oils become fully oxidized and have attained the desired degree of fermentation. This process turns the leaves black and produces the deep, sometimes pungent flavor associated with black teas. The process also destroys the majority of the powerful antioxidants and vitamins (C, B-complex, E) found in tea leaves.
Black teas account for over 90% of the tea sold in the United States and Europe. Well-known varieties of black teas include Darjeeling, Ceylon, Assam, China Black, Java, Nepal, Nilgiri, Sikkim and Pu-Erh. They are named after the region in which they are grown. Some of the most popular black teas are a blend of two or more teas. Among them are Earl Grey (Darjeeling, Ceylon, infused with bergamot), English Breakfast (Ceylon, Assam, Nilgiri), Irish Breakfast (Assam, Nilgiri) and chai (various Indian black teas flavored with cinnamon, vanilla, ginger and sometimes lemongrass). Becoming more popular are black teas flavored with herbs and fruits, including apple, orange, blackberry, cranberry, ginseng and the like.
