Black tea is fermented tea, and is currently the most popular choice in the UK. The tea leaves are picked, withered and then rolled. The process of rolling brings aromatic oils to the surface and encourages oxidization. The rolled leaves are usually left for around two hours. Finally the leaves are fired in an oven with temperatures reaching up to 200 degrees Fahrenheit. Once 80 percent dry, the leaves complete their drying over wood fires. The resulting product is brownish (sometimes black) in colour and is sorted accordingly to size - the larger grade is "leaf grade," and smaller "broken grade" are usually used for tea bags.