What is Green Tea?
Green tea is made from Camellia sinensis leaves which have not undergone any withering or oxidation processes used to make other kinds of tea such as oolong or black teas.
Originating from China before spreading to many other countries within Asia, there are many different types of green tea based off the variety of Camellia sinensis used, growing conditions, horticultural methods, production processing, and time of harvest; all which can drastically change the leaves appearance and flavour.
The ancient Chinese first discovered the tea plant in what is now southern China and used it at first as a medicinal herb. Back then they used to immediately steam the fresh tea leaves and dry them for preservation. They perfected this method near the end of the Han Dynasty (206 BCE-220 CE) and produced a dried tea leaf which would now be classified today as "green tea" which was quite similar to modern Japanese sencha.
To drink they would either steep in water around with other herbs or ground into a powder (matcha) to be taken straight or added to water. As Chinese herbology increased in popularity the production methods changed to include creating bricks of tea for easily transported and storage. They did this by steaming the leaves to creating a paste which they then pressed into molds or by using a cooked rice slurry to bind whole leaves together into bricks.
Here and Now
Now there are dozens of different green teas which are consumed all over the world and is second only to water. We also drink green tea for both pleasure and for its medicinal benefits. Loaded with antioxidants which help fight back against cancer while promoting overall body wellness, it also has minerals and EGCG (Epigallocatechin Gallate) which is a powerful compound used to treat various diseases and likely the main reason green tea has such powerful medicinal properties.
As to the taste? Well, many people believe it to be bitter and gross, but they've just been doing it wrong.