Matcha (抹茶, Japanese pronunciation pronounced [mat.tɕa], English /ˈmætʃə/[i]) is finely ground powder of specially grown and processed green tea leaves. It is special in two aspects of farming and processing: the green tea plants for matcha are shade-grown for about three weeks before harvest and the stems and veins are removed in processing. During shaded growth, the plant Camellia sinensis produces more theanine and caffeine. The powdered form of matcha is consumed differently from tea leaves or tea bags, and is dissolved in a liquid, typically water or milk.
There are also several harmful effects of green tea over-consumption that are possible. These include consuming tainted supplements marked as green tea extract, high caffeine consumption, consuming aluminum, and the effects of tea polyphenols on iron bioavailability. Green tea extracts should not be taken by patients suffering from renal failure, liver disease, heart conditions or major cardiovascular problems without supervision from a doctor. People sensitive to caffeine should be careful of their intake. Pregnant and breast-feeding women should drink no more than one or two cups per day, as some research shows that more caffeine than this amount may interfere with normal heart rhythms.
Loose leaf green tea has been the most popular form of tea in China since at least the Southern Song dynasty. While Chinese green tea was originally steamed, as it still is in Japan, after the early Ming dynasty it has typically been processed by being pan-fired in a dry wok. Other processes employed in China today include oven-firing, basket-firing, tumble-drying and sun-drying. Green tea is the most widely produced form of tea in China, with 1.42 million tons grown in 2014.
Another big draw health benefit-wise is that matcha, like green tea, is loaded with antioxidants. A study, published in 2014, found the plant also had antimicrobial properties, particularly the four types of catechins (antioxidant properties flavonoids) it contains, against a few different types of microorganisms. Yet another study, published in Nature, proved that catechins inhibit the growth of a bacteria called Fusobacterium nucleatum — the bacteria that causes cavities and periodontal disease.
Grown under shade for three weeks prior to plucking, gyokuro is one of the most exclusive varieties of tea produced in Japan. The shading technique imparts a sweeter flavor, and produces a particularly rich color thanks to the higher amounts of chlorophyll in the shaded leaf. Gyokuro tea is associated with the Uji region, the first tea-growing region in Japan. It is often made using smaller-leaf cultivars of the tea plant.