Formosa tea is a type of tea grown and processed on the East Asian island of Taiwan, which was dubbed "Ilha Formosa" or "beautiful island" by 16th-century Portuguese explorers. Most varieties of formosa tea are classified as oolong teas, although the island of Taiwan also produces a gunpowder tea known as Formosa gunpowder. Generally, teas produced in this region of the world are considered to be of high quality, with a heady, intense, sometimes smoky aroma and flavor. The tea is usually consumed as a hot beverage, although it can also be used in cooking to add flavor to sauces or rice dishes.
Taiwan's tea industry is relatively young. The island's tea production began in earnest during the middle of the 19th century. Growing conditions for tea are not always ideal in Taiwan, because the island is a patchwork of many different climates despite its small size. Therefore, the aroma, flavor, and overall quality of Formosa tea can vary greatly, depending on where the tea leaves were grown.
Most types of formosa tea fall under the category of oolong tea, a type of tea that is traditionally brewed in China. Oolong teas are considered neither black nor green, as they are lighter in color and less fermented than black tea, but darker in color and more fermented than green tea. Typically, formosa tea leaves appear red or copper after processing.
Formosa tea is made by picking tea leaves while they are still green and leaving these leaves in the open air to sun-dry for a short period of time. During this time, the leaves "ferment," a term used by the tea industry to describe the breakdown of chlorophyll, or the substance that makes leaves green, and the activation of tannins, which are the organic plant compounds that give most teas a distinctively bitter flavor. Formosa tea's fermentation is abruptly halted when the leaves begin to brown around the edges by heating them over a fire. The process of allowing the leaves to partially ferment is different from that used to make green tea, which is left "green" and not fermented at all. It is also slightly different from the process used to make black tea, which is usually allowed to ferment completely.
After fermentation has been halted by heating the tea leaves, the leaves, which are still slightly damp, are rolled into tubes or spheres. This process can be done either by machine or by hand, although machine rolling is much more common in modern times. Once rolled, the tea leaves are heated again to dry them out. Formosa gunpowder is a variety of Formosa tea in which the leaves are rolled very tightly to form tiny pellets whose appearance is somewhat reminiscent of grains of gunpowder, hence the name. These pellets often "bloom" in an attractive way when hot water is poured over them, and frequently produce a very strong, concentrated tea.