Shimeji Mushrooms

FIND - Buna- and bunapi-shimeji mushrooms (brown and white varieties respectively) are increasingly common in grocery stores, but are most common in Asian grocery stores or in areas with large East Asian or Italian populations. Look for them in the produce section along with other mushrooms, often in cellophane-like micro-porous plastic packages.

In parts of North America, Europe, and East Asia, buna-shimeji can be found growing wild.  That being said, they are far more easily obtained from commercial operations, especially given their habit of growing high up on a tree.  Only harvest wild mushrooms if you are absolutely certain of their identity and safety.

STORE - If you’ve purchased mushrooms in a little plastic tub with a cellophane-like plastic covering, leave the mushrooms in this until you’re ready to use them. Shimeji mushrooms store quite well in the refrigerator if they’re given a chance to breathe a little. The cellophane-like plastic is actually microporous, allowing air through, but keeping dirt and grime off. If you leave this packaging on, your mushrooms will keep in the refrigerator for several weeks. If the mushrooms are packaged in a non-porous material (e.g. plastic wrap), they will not keep as well. In this case, they should be transferred to a paper bag, kept in the refrigerator, and used within 5 days.

When they get a bit too old, shimeji mushrooms can start to look a little soft, and may start to grow a powdery, fuzzy surface. This fuzz is not mold, but the mycelia (structures somewhat like the ‘roots’ of a fungus) of the shimeji mushroom itself. They are growing because the fungus is attempting to expand beyond its mature stalks and re-establish itself. If this happens, the mushrooms can be washed/scrubbed a little more vigorously and then used normally. Soft, dark or particularly ‘furry’ mushrooms indicates spoilage and should be discarded.

As with most mushrooms, uncooked shimeji mushrooms do not freeze well.

While often sold simply as ‘shimeji’ mushrooms, that name actually applies to a confusingly large number of mushroom species and varieties.  This page deals with the brown and white beech mushrooms (buna- and bunapi-shimeji respectively).  These are sometimes marketed as “Hon-shimeji,” but this name correctly applies to a different mushroom that has only recently come under commercial cultivation.

Buna-shimeji are saprophytic mushrooms commonly found on beech trees, giving rise to the common name ‘beech mushroom‘.  They can still be found in the wild in East Asia and parts of Europe, however they are readily cultivated and are commonly found in grocery stores.

Bunapi-shimeji (white beech mushrooms) are a white variety first isolated and subsequently trademarked by the Hokto corporation of Japan.

The Italian names chiodini and pioppini have been applied to these mushrooms, though they were originally used to describe other species with a similar appearance.  This is unsurprising, since the mushrooms have only become popular outside of Japan in recent decades.

As mentioned above, the word shimeji may be applied to other species as well, including the hon-shimeji mushroom (Lyophyllum shimeji) and the Hatake-shimeji mushroom (Lyophyllum decastes).  Neither of these mushrooms is commonly found outside of Japan, and both look quite different from the small-capped shimeji mushrooms shown here.

Organic and conventionally grown shimeji mushrooms are available commercially.  Because mushroom growing is largely done without added fertilizers or pesticides, the primary determining factor for organic status is the origin and makeup of the substrate used to grow the mushrooms.

Hokto (the American subsidiary of Hokuto Japan), one of the biggest suppliers of shimeji mushrooms, grows all of its products under US certified organic standards.  There has been some concern over the labeling of these products, and legal action has been taken in at least one instance to prevent conventional growers from appropriating the packaging and details of an organic product (see here).

In order to meet organic standards, Hokto grows all of their fungi on an organic, non-gmo corn and rice bran. FINC (Shanghai Finc Biotech), one of the bigger Chinese producers of shimeji mushrooms, is not certified as organic, but uses pesticide-free production methods and conforms to China Green Food standards.  Other growers may or may not follow organic practices – refer to individual producers data for more information.