Taiwan is known for producing the world's finest gunpowder teas. They should be, they've had a lot of practice – tea plants were first brought to the island over 300 years ago from Fujian province in China. Tea growers recognized that Taiwan had the climactic conditions and topographical features required for producing excellent teas, these being lofty mountain meadows, fresh water and wet humid conditions. In fact, the conditions make it possible for tea bushes in Taiwan to flush 5 times a year from April to December with the best teas plucked from the end of May to mid August. (The flush is a period of exceptional leaf growth.) The exact origin of gunpowder production is unknown but at one time, but before 1900 gunpowders accounted for 60% of American tea imports, such was its popularity.
The process for making gunpowder was, and still is, rather complicated. First, freshly plucked green leaf is pan-fired at between 280 and 300º C to keep it from fermenting. In early times, this would have been done by hand in large wok shaped pans, today it is done by machine. Next, the leaves are rolled to facilitate molecular breakdown in the leaf, release flavor and make the leaves more pliable for shaping. After rolling the leaf is broken into smaller pieces and sent to the primary dryer. The tea is sent through this dryer 3 times for 30 minutes at around 125º. After drying the leaf is sent to therolling machine. Depending on the style being produced that day, different shaped machines are used. In the case of gunpowder the roller is a round drum that turns the tea over and over in on itself. The final stage, the one that gives gunpowder its signature glossy look and brittle texture is secondary drying at temperatures ranging from 70º to 100º depending on ambient humidity. At the end of the process the leaf should have a moisture content of no more than 5% and be tightly wound into a neat ball-like shape.