Green teas are the least processed of all the types of tea and are often referred to as “unfermented” or “non-oxidized” teas. The intent is to preserve the natural "green" characteristics of the tea plant.
In the traditional producing countries of China and Japan, the finest green teas are picked during the spring season when the delicate, young leaves and leaf buds contain their highest concentration of aromatic oils.
As soon as the tea leaves are picked, a natural process called oxidation begins. Oxidation occurs when the enzymes in the leaf react with oxygen in the air, causing the leaves to change in color from green to yellow, to amber and red, and finally to brown. The level of oxidation is what distinguishes the various tea types - green, white, oolong and black.
To produce green tea, the oxidation process must be interrupted early and this is achieved through the application of heat, in a step known as "firing". In China, teas are fired using a variety of dry heat methods such as pan roasting, oven baking and sun curing. These methods result in teas with an aromatic quality reminiscent of grilled or toasted nuts. By contrast, in Japan, the fresh picked leaves are steamed for a short period of time. This method fixes the bright green color and imparts umami-rich notes of seaweed and spinach.
After firing, the leaves are shaped into various styles - twisted, curly, balled and needle - each with its own character, flavor and aroma.