Why You Should Be Using Shiitake Mushrooms More—Plus How to Buy, Store, and Cook Them
What the button mushroom is to the U.S., the shiitake is to East Asia is (but more delicious)—they are the most popular and widely sold mushroom in that region. Luckily for us, shiitakes are increasingly common stateside. The flavor and texture of shiitakes—ultra-savory and buttery with a meaty texture when fresh, smokier when dried—make them a highly desirable ingredient. Here's everything you need to know about this wonderful fungi.
History of Shiitake Mushrooms
The history of shiitake cultivation dates back over 1,000 years in Japan and China where wild, forest-grown mushroom-producing logs were placed beside felled logs of the same tree type, according to renowned produce expert Elizabeth Schneider, author of Vegetables from Amaranth to Zucchini. Its Japanese name, shii refers to one of the species of forest trees on which shiitake commonly appear, Castanopsis cuspidata, or Japanese chinkapin, an oak native to Japan and Korea says mycologist Paul Stamets. It belongs to the beech family, and the mushrooms can grow on other trees in that family, too. Take means mushroom, in Japanese (which is why saying "shiitake mushroom" is redundant).
Shiitake are classified scientifically as Lentinus edodes. Other names include fragrant mushroom, golden oak mushroom, Chinese black mushroom, and black forest mushroom. We will refer to the Japanese terms, since that is how they are best known in the U.S.
In the Wild
Shiitakes are forest dwellers native to East Asia, growing in groups on dead deciduous hardwoods. They are saprobes, living on decaying organic matter, in this case, wood. In complex relationships with other microorganisms, they transform fallen trees into soil components.
Modern mushroom-growing technology—and shiitakes' amenability to domestication as well as culinary and medicinal value—has made shiitakes the most cultivated mushroom in East Asia. In the U.S., most of the mushrooms available are imported from Asia but rapidly expanding American-grown supply is catching up.
In the U.S., shiitake have been cultivated only since the early 1980s, and the variety of grades available is still limited to specialty markets. Commercially raised shiitake might be greenhouse or forest-grown, either in sawdust-stuffed bags or beds by an agro-business, or on inoculated logs on family farms (the difference will be noticeable in price and quality). Forest-grown shiitake have a reputation for better flavor since they respond to natural fluctuations in temperature and moisture and are not raised in a sterile, highly controlled environment. You can even grow shiitake at home using grow kits.
You'll likely find shiitakes in the produce section of many supermarkets. For a wider selection, turn to grocery stores catering to East Asian customers, which will stock various grades of shiitake, as well as specialty mushroom growers online. Shiitake can also sometimes be found at farmers' markets.
How to Choose and Store Fresh Shiitake
Choose fresh shiitakes with firm and velvety caps. Avoid any that have wet or slimy spots. Ideally, remnants of the veil over the gills should be present. The cap edges should be curled under towards the gills. Wide caps with soft edges can be flabby in texture; small caps are meatier.
At home, keep shiitake chilled and covered for a few days until you use them, then wash. Trim off the tough stalks (they are chewy but you can save them to dry for broth).
Grades of Shiitake
If you saw them side-by-side for the first time, you would be forgiven for assuming that the different types of shiitake belong to different mushroom species. The variations in appearance reflect how they were grown and when they were harvested. (The terms we are using reflect transliterated Japanese names.)
Most of the shiitakes available at U.S. markets have open, flatter caps, and are considered koshin grade shiitakes, which is the most basic, but also the most aromatic. Koshin (or fragrant) shiitake are the most mature form of the mushroom. Koshin shiitake are harvested after the cap has fully opened or "bloomed." They have relatively thin, flatter caps and exposed gills. This stage of shiitake has the strongest aroma.
Donko are a higher grade of shiitake and are identified by their smaller, firm, thick caps with rolled-under edges. They are known as winter mushrooms, traditionally developing more slowly in colder temperatures and becoming denser and meatier in flavor. Mostly, they are simply harvested before the mushroom has fully matured. Ideally, their veils would be intact or semi-intact (veils look like a fine spider web or net, covering the gills).
Tenpaka and Chabana Donko
Tenpaka and chabana donko—known as flower mushrooms—are the most sought-after, premium shiitake, and more intense in flavor. To the untrained eye, they look like a different species. Both have distinctively crackled tops featuring fissures or cracks in their thick caps, caused by sudden temperature and moisture changes during cultivation. The cracks in tenpaka are snowy-white. In the U.S., flower mushrooms can usually only be found at Asian fresh produce markets.
All grades of shiitake are also sold dried. When reconstituted in hot water, their flavor is significantly more pronounced. Reconstitute dried mushrooms by soaking in hot water and then squeezing out the excess water.
Shiitake as Functional Food
Shiitake contain eritadenine, which has cholesterol-lowering properties. In laboratory studies (i.e., not in animal or human studies) lentinan—a polysaccharide isolated from shiitakes—kills viruses and bacteria. In vitro studies suggest that it boosts immunity and may have potential benefit in cancer treatments.
Can You Eat Shiitake Raw?
Any type of mushroom should be fully cooked or they can cause gastric distress due to their chitin content. Rarely, raw, or slightly cooked shiitakes can cause an allergic reaction known as "shiitake dermatitis," this may be due to their lentinan content.