and intensification of their flavor compounds. From the moment they are plucked, the cells within the tea leaves are exposed to oxygen and the volatile compounds within them begin to undergo chemical reactions. It is at this stage that polyphenolic oxidase, including theaflavin and thearubigin, begin to develop within the leaves. Theaflavins lend briskness and brightness to the tea while thearubigins offer depth and fullness to the liquor that's produced. In order to bring out specific intensities in flavors, tea makers control the amount of oxidation the leaves undergo. Controlled-oxidation is typically carried out in a large room where the temperature is maintained at 25–30 °C and humidity stands steady at 60–70%. Here, withered and rolled leaves are spread out on long shelves and left to ferment for a fixed period of time, depending on the type of tea being made. To halt or slow down oxidation, fermented leaves are moved to a panning trough where they are heated and then dried. Due to oxidation, the leaves undergo a complete transformation and exhibit an aroma and taste profile that's completely different from the profile of the leaves that do not undergo this process. Less oxidized teas tend to retain most of their green color and vegetal characteristics due to lower production of polyphenols. A semi-oxidized leaf has a brown appearance and produces yellow-amber liquor. In a fully oxidized tea, amino acids and lipids break down completely, turning the leaves blackish-brown. The flavors in such a tea are more brisk and imposing. Rolling involves shaping the processed leaves into a tight form. As a part of this procedure, wilted / fixed leaves are gently rolled, and depending on the style, they are shaped to look wiry, kneaded, or as tightly rolled pellets. During the rolling action, essential oils and sap tend to ooze out of the leaves, intensifying the taste further. The more tightly rolled the leaves, the longer they will retain their freshness. Drying In order to keep the tea moisture-free, the leaves are dried at various stages of production. Drying enhances a tea's flavors and ensures its long shelf-life. Also, drying brings down the tea's moisture content to less than 1%. To dry the leaves they are fired or roasted at a low temperature for a controlled period of time, typically inside an industrial scale oven. If the leaves are dried too quickly, the tea can turn abrasive and