Genmaicha
Genmaicha (玄米茶; 'brown rice tea') is a Japanese green tea combined with roasted popped brown rice. It is sometimes referred to colloquially as "popcorn tea" because a few grains of the rice pop during the roasting process and resemble popcorn, or as "people's tea", as the rice served as a filler and reduced the price of the tea, making it historically more available for poorer Japanese.