Green tea that has been rolled into pellets, which unfurl in hot water to brew.
Gunpowder tea is a form of green Chinese tea produced in Zhejiang Province of China in which each leaf has been rolled into a small round pellet. It is believed to take its English name from the fact that the tea resembles grains of black powder. This rolling method of shaping tea is most often applied either to dried green tea (the most commonly encountered variety outside China) or Oolong tea.
Gunpowder tea production dates back to the Tang Dynasty 618–907 CE. It was first introduced to Taiwan in the 19th century. Gunpowder tea leaves are withered, steamed, rolled, and then dried. Although the individual leaves were formerly rolled by hand, today most gunpowder tea is rolled by machines (though the highest grades are still rolled by hand). Rolling renders the leaves less susceptible to physical damage and breakage and allows them to retain more of their flavor and aroma. In addition, it allows certain types of oolong teas to be aged for decades if they are cared for by being occasionally roasted.
When buying gunpowder tea it is important to look for shiny pellets, which indicate that the tea is relatively fresh. Pellet size is also associated with quality, larger pellets being considered a mark of lower quality tea. High quality gunpowder tea will have small, tightly rolled pellets.