As a result of minimal processing, green tea retains its natural appearance and vibrant color as well as high levels of the plant's healthy properties. To prevent oxidization, the leaves are heat processed to eliminate the enzyme responsible for oxidization. In China, this is generally done by roasting or pan-firing the leaves, while the Japanese generally accomplish this by steaming the leaves at a high temperature. Green tea varies dramatically in flavor from grassy and sweet, to floral and fresh, to nutty and roasted. Like fine wine, green tea's flavor depends on the plant varietal, season of harvest, soil, elevation, weather, cultivation and origin. Each region has its own distinct flavor and aroma.