Babelcarp, after thinking about it, responds:
zhucha (Zhu Cha) = so-called gunpowder tea, pelletized lücha, literally Pearl Tea (珠茶)[1,2]; also, (筑茶 or 築茶)[4,2] literally Rammed Tea: the characteristic raw material of compressed haojicha, shaiqing maocha that has been moistened, pounded into a bamboo basket, and then stored for some time