Shiitake mushroom

Shiitake (Lentinula edodes) is a wood-decaying mushroom native to East Asia. In the wild it grows on dead broadleaf trees such as chestnut and various oaks. The cap, typically 3 to 6 centimeters across, is dark brown to blackish brown, with tough, meaty flesh that dries well. In China it has traditionally been ranked the finest of mushrooms, while in Korea and Japan the pine mushroom (songi) commands the highest price.

Most shiitake today is cultivated. In the traditional log method, oak or chestnut trees of about twenty years are felled in late autumn as the leaves fall, left to dry until spring, cut into logs about a meter long and inoculated through notches in the bark. The logs are then stacked in moist woodland shade; mushrooms appear in quantity from the second year and keep coming for five or six years. Shiitake is also grown on sawdust-based blocks (baeji), the method behind the nutrition figures below. Jangheung County in South Jeolla is a leading producing area, especially for dried shiitake.

Drying transforms the mushroom. Its distinctive aroma comes from lenthionine, which develops as it dries, and its savory depth from guanylate, a nucleotide that ranks among the strongest umami compounds. Dried shiitake should be soaked only briefly, and the soaking water kept, because flavor compounds dissolve into it.

In Korean cooking, shiitake is added to vegetable dishes, where it lends a richness that can rival meat, and is used in stir-fries, broths and braises.

• Low in calories: Fresh shiitake provides about 22 kcal per 100 g along with 5 g of dietary fiber (Korean Food Composition Table).
• B vitamins: It is a source of niacin, riboflavin and thiamin.
• Flavor without salt: Its natural umami can add depth to broths and vegetable dishes, which may help cooks use less salt.
• Shiitake dermatitis: Eating raw or undercooked shiitake can, in some people, cause a distinctive itchy, streaky rash that appears hours to days later and usually clears on its own within weeks; it is attributed to lentinan, a heat-sensitive compound in the mushroom. Cook shiitake thoroughly.
• Research claims: Compounds such as eritadenine and lentinan are studied for possible health effects, but evidence in people is limited and research is ongoing.