Tea trees bud from late April to early May. At first farmers pick young buds and fresh leaves. And then they steam and roll them by hand or by machine. Finally they dry them. Steaming and rolling fresh tealeaves ruins the oxidizing enzyme. But steaming and rolling make it possible to keep aroma, color, and Vitamin c. There are the most various kinds of Sencha. Japanese drink Sencha in our daily life. Its leaves grow bigger and bigger under the sunshine. And their leaves grow thick and deep green and smell strong. Sencha tea tastes strong compared with Gyokuro. Sencha also contains vitamin c that is hard to be broken down by heat. Sencha contains catechin, a sort of tannin, that has strong sterilizing effects. Sencha draws many people's attention because of its strong effects against Verotoxin-producing Esherichia coli.also known as O-157. Many students of primary school died some years ago because of O-157 found in their school lunches.