deep-steamed green tea
A type of Japanese green tea (sencha) that is steamed for a longer time than usual, resulting in a deeper color, richer flavor, and less astringency.
Deep-steamed green tea has a mellower taste than regular sencha.
Compound of 深 (fuka, 'deep') + 蒸し (mushi, 'steaming') + 茶 (cha, 'tea'). The term directly describes the longer steaming process used in its production.