Sencha tea is a Japanese green tea — the most widely produced and consumed in the country. Its popularity comes not only from its taste, which is slightly sweet and astringent, but also from its purported health benefits. The tea is a rich source of antioxidants, and health benefit claims include weight loss, anti-aging effects and even the prevention of heart disease and cancers.
Japanese plantations produce the sencha leaves, with each region producing a distinct flavor of tea leaves. Leaves are harvested during April and May, and the first new tea leaves are especially sweet. Sencha tea leaves are steamed for a few seconds before they are rolled and dried. Finally, when the drying process is complete, the leaves are fried as a preservative measure.
Steaming makes Japanese teas such as sencha tea distinct from Chinese green teas, and it gives the Japanese teas a grassier, vegetal flavor. Steamed tea leaves make a greener tea than leaves that are roasted, as they are for Chinese teas. The steaming process also helps to prevent oxidation and gives the tea a longer shelf life.
The tea is made by decoction, using whole leaves to infuse the hot water. The water temperature will have a strong effect on the taste, with boiling water bringing out more of the astringent flavor. For a mellower, sweeter cup, water should be boiled and then left to cool for two minutes before making the tea.
Health benefits and medicinal uses have not been proved, but a large body of anecdotal evidence and health claims exist. As a rich source of antioxidants, sencha tea might offer a host of health benefits as well. Green tea contains catechin, a potent antioxidant more effective than vitamins C or E. Antioxidants are believed to diminish signs of aging and reduce the chance of heart disease.
Antioxidants found in green tea might even have applications in the fight against cancer. Studies are encouraging, but there are some conflicting results. The effects of some chemotherapy and anti-cancer treatments, however, might be reduced by green tea, and a medical professional should be consulted before sencha tea is consumed during treatment.
Green tea also might help regulate blood sugars, which can help prevent diabetes. It might have a cholesterol-blocking effect, and it might help the body remove cholesterol in the bloodstream as well. Polyphenols found in sencha tea might speed up metabolism, and dieters have turned to this tea to help with weight loss for this reason. These teas also contain theanine, an amino acid that is believed to help with relaxation.