Shimeji mushrooms are small to medium in size and have rounded caps with semi-thick stems. When young, the caps are dark brown, and as they mature they lighten to buff-tan with a white ring around the edges. The caps are also smooth, convex, firm, and are moist, but not slimy. The white stem is spongy, averaging ten centimetres in length and two centimetres in diameter, and is dense and meaty. Shimeji mushrooms are chewy with a bitter taste when raw, but when cooked, they develop a tender, nutty, umami flavour and are mild with a hint of radish.