Black Teas are made by - Withering - The plucked leaf is first spread on racks in a current of warm, dry air. This removes the moisture from the leaf, leaving it limp. Rolling - The withered leaf is crushed by rolling, or cutting, tearing and curling. This releases the natural juices. Fermentation - The crushed leaf is then allowed to ferment to a bright, coppery color. The leaves have absorbed oxygen which causes the color change. Drying - The fermented leaf is then dried by hot air to become the familiar black tea.