Fukamushi-cha (Deep-steam Green Tea) (深蒸し茶)
Fukamushi-cha (deep-steam green tea) is a type of sencha. When making fukamushi-cha, steaming, the first process in making sencha from raw tea leaves, is performed for longer at between one and three minutes. While tea leaves are normally steamed for between ten seconds and one minute prior to the drying or rubbing process so that the cells of tea leaves will soften and extracts its ingredients, the tea leaves are steamed for longer in the case of Fukamushi-cha so that the tea is further infused with its ingredients, making its taste richer and mellower than that of normal green tea. The resulting fukamushi-cha is dark green and cloudy.
The History of Fukamushi-cha
It is said that Fukamushi-cha was developed by tea farmers in Kikukawa City between the late 1960s and early 1970s. Tea leaves from Makinoharadaichi, including Kikugawa city, used to grow to become thick and hard because they were exposed to longer hours of sunlight. This resulted in the production of bitter tea. After researching how to make bitter tea milder, the tea leaf fibers were softened by steaming for a longer period of time to successfully produce a green tea from which the bitter taste had been eliminated. It is because of this that even now, Kikukawa City is called the home of fukamushi-cha.
Reference
Some call tea steamed for 10 to 20 seconds asamushi-cha (light-steamed green tea) (most hand-rubbed tea belongs to this group), and tea steamed for 20 seconds to one minutes futsumushi-cha (normal-steamed green tea), but these are not very popular as tea manufacturing terms.
Because the long steaming time makes the flavor weaker, it may be blended with other teas such as gyokuro (refined green tea) in order to supplement the flavor.
By its nature, fukamushi-cha tends to contain powder-like fine leaves, so it tends to clog teapots. However, this can be avoided by using special fukamushi-cha teapots.