Buckwheat tea is indeed made of buckwheat. However, buckwheat tea is not composed entirely of buckwheat grains, but the seeds of buckwheat after sifting, roasting and other processes processed from the punch.

As for why buckwheat tea like popcorn is fluffy, it may be because buckwheat grains after screening, roasting and other processing, the internal water gradually evaporated, resulting in its internal organization becomes loose, thus forming a structure similar to popcorn. In addition, buckwheat tea processing may be some of its treatment, such as puffing, compression, etc., which may also contribute to the formation of buckwheat tea unique fluffy structure.

In short, although the main ingredient of buckwheat tea is buckwheat, but after specific processing, its appearance and structure will be similar to the fluffy form of popcorn.