Shiitake

What it is

Shiitake (Lentinula edodes) is a brown, umbrella-shaped mushroom with a tough stem and a cap that often cracks into a pale pattern as it dries. It's native to East Asia, where people have grown it on logs for centuries, and it's now grown across the US. Fresh shiitake from a local farm will usually be one of two kinds: log-grown or block-grown.

Taste and cooking

Shiitake has a deep, savory flavor, with more umami than most fresh mushrooms. Log-grown caps tend to be thicker and denser; block-grown ones are more uniform.

• Remove the stems. They're woody. Twist them off and keep them for stock.
• Cook it all the way through. Sear slices in oil until browned and tender, or roast whole caps gill-side up with a little soy sauce.
• Dried shiitake is a pantry staple. Soak it in warm water until soft, then use both the mushrooms and the soaking liquid.

There's a specific reason to skip raw or lightly cooked shiitake. Some people get a streaky, itchy rash called shiitake flagellate dermatitis after eating it raw or undercooked; dermatologists have described it in case reports (Ma et al., 2022). Thorough cooking is the usual advice.

How it's grown

On logs. Ohio State's extension fact sheet on shiitake production recommends hardwood logs, with white oaks preferred, about 3 to 4 feet long and 4 to 6 inches across. Growers drill rows of holes, fill them with sawdust or dowel spawn, and seal them with wax. The logs rest in a shaded, well-drained "laying yard" while the fungus colonizes the wood, which takes six months to two years. After that, soaking a log in water for a day or two can trigger a flush of mushrooms. Log-grown shiitake is mostly a spring-through-fall crop.

On blocks. Most commercial shiitake grows indoors on blocks of supplemented hardwood sawdust. The blocks colonize, form a brown skin, and fruit in a humid room. This is how farms supply shiitake year-round.

If you want to try logs yourself, our home growing guide links the Ohio State fact sheet and Cornell's small-farm resources.

Storing it

Shiitake holds up better than most fresh mushrooms. Refrigerate it in a paper bag or the original container (Penn State Extension's guidance for fresh mushrooms) and use it within a few days. Fresh caps are firm, dry and evenly colored, with gills that look clean. Dark wet spots, slime on the gills or a sour smell mean it's old. Dried shiitake keeps for months in a sealed jar.

Where to buy shiitake

16 growers in our directory list shiitake by name@if ($ohio->isNotEmpty()), 6 of them in Ohio. Availability changes with the season and the harvest, so check with the farm before you go.

See all 16 growers in the directory, or start with Ohio.

Does the science say…?

Shiitake contains beta-glucans, including a compound called lentinan, and it's been studied for effects on the immune system.

• In a 2015 University of Florida study, 52 healthy adults ate a small daily portion of dried shiitake for four weeks. Afterward, researchers saw changes in several immune measurements in blood and saliva samples, including increased proliferation of certain immune cells and lower C-reactive protein, a marker of inflammation (Dai et al., 2015). The study measured lab markers. It didn't test whether people got sick less often, and it had no group that ate no mushrooms.

That's a reasonable sign that shiitake is worth studying as a food. It isn't evidence that eating shiitake prevents or treats any illness.