I am a big fan of green tea, since I was a child. I must drink Japanese green tea with Japanese food, not with any other drink in the world. A good cup of good green tea has a very complex flavor with wonderful balance of sweetness, bitterness, aroma, and even umami. Such high quality tea is rather rare and not for everyday consumption, but I absolutely refuse to drink tasteless green tea.
Chinese also drink green teas, a lot. Chinese green teas are more readily available in the United States than Japanese ones, and named gunpowder or dragonwell. Both Chinese and Japanese green teas are not oxidized, but the method to stop oxidation is different.
Chinese green teas are roasted, but Japanese green teas are steamed. The difference in the process creates very different flavor. While Chinese brew it with hot boiling water, Japanese teas require lower temperatures, ranging from 131℉ (55℃) to 212℉ (100℃) depending on the types.
As a side story, all kind of teas, white, green, oolong, black, and pu-erh are made from just one kind of plant, camellia sinensis. Depending on the cultivated area, quality, and process, different teas are produced.
For people who drink green tea a lot, brewing loose tea leaves in a pot is more convenient and economical, because unlike teabags, loose leaves give 2~3 brews before changing the leaves. Also the tea brewed from loose leaves tastes much better than the tea made from a teabag. Decent Japanese loose green teas are hard to get in the U.S.
Green tea leaves, or any other tea leaves suck moisture quickly. When it happens the quality deteriorates. When you buy green tea in the United States, buy vacuum sealed ones. Green tea is raw, and should be treated like a perishable item. Sealed green tea leaves should be stored in a freezer. Once it’s open, store it in a tightly sealed container to keep moisture out in room temperature, and ideally finish within a month.
There are canisters in Japan made exclusively to store tea leaves. Most of them are made of tin or aluminum, but some of them are made of wood, such as cherry barks. As I love teas, I also ended up collecting tea storage containers. Some of them are wrapped with cute printed washi paper.
Teabags are handy, but tasteless. One exception is Costco’s (Kirkland brand) green tea, made by Itoen, which is a reputable Japanese tea brand. They can be stored at room temperature, as the individual teabags are sealed in aluminum packages. For those who wish to order online, here are some recommendations;