Homiclub
Wood ear mushroom
Type
Mushrooms
Difficulty
Moderate
Season
Spring·Summer·Fall
Sowing
From spawn
Mushrooms

Wood ear mushroom

Auricularia heimuer

Fibre, beta-glucan · a cultivated mushroom on oak

Wood ear grows on dead hardwood, oak above all. In a city there are two practical routes: stand oak logs inoculated with spawn in light shade, or buy a sawdust block already colonised and simply hold the humidity. Dried wood ear swells five or six times in water and comes back to its springy, cartilaginous bite. Keep the soak short and soak only what will be cooked; if it has to stand overnight, put it in the refrigerator. Wood ear left soaking for hours at room temperature grows bacteria and turns sour-smelling, and the toxin formed there is heat-stable, so boiling will not remove it and the batch goes out whole. The Donguibogam lists it in the Vegetable section as 木耳 with the Korean name of the period, giving it a cold nature, called neutral by some, a sweet taste and no toxicity. The same entry separates 菌, which grows from the ground, from 檽, which grows on wood, and even records a cultivation method: elm, willow, mulberry, pagoda tree and paper mulberry are grouped as the five mushroom woods, and if gruel is boiled, laid over the wood and covered with grass, mushrooms come up.

Where It Grows

ChinaSouth KoreaJapan
Main producer Major producer Wild population Latitudes at 20–28℃ Zoom and pan to explore · temperatures are rough zonal averages
  • Main producer The broadleaf forest belt of Heilongjiang and Jilin is the center, and it yields most of the world's production. It is grown on logs and on sawdust substrate.
  • Major producer It is grown on oak logs and sawdust substrate, and it also occurs wild on dead broadleaf wood. Harvest June, July, August, September, October
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  • Wild population It occurs wild on dead wood in the broadleaf forests from Honshu southward. More is brought in from abroad than is grown at home.

Its place is the temperate broadleaf forest of East Asia, and within that, the dead wood of oaks. Cultivation is heavily concentrated in China, so most of the dried wood ear in trade is Chinese. What is grown in tropical Southeast Asia belongs to the hairy wood ear group (Auricularia cornea), a different species, so the thick, chewy kind is taken to be that one.

Optimum
20~28℃
Range
15~32℃
Hardiness
Hardy
Day length
Not applicable

Humidity decides when it fruits. The mycelium runs through the log at 25~30℃, and the fruiting bodies come up at 20~28℃ after rain. Inoculated logs overwinter in the open — they are left outdoors through the cold months — and come up again the following year, and where direct sun reaches them they dry and shrivel onto the wood.

Harvested 1–4 years after planting. Logs spawned in March or April give a little that same summer and come into proper bearing from the following year, fruiting again and again over three or four years. The year of inoculation and the year of the real harvest are not the same.

In Korea Nationwide

It comes up on dead wood in broadleaf forests across the country, and what is cultivated is grown on oak logs and sawdust substrate. From summer through autumn it fruits after every rain.

How to grow

Light
Keep it out of direct sun. Bright shade under trees or shade cloth is right
Soil and depth
Nothing is planted in soil. Oak logs or sawdust blocks are the substrate, propped clear of bare ground
Spacing
Lean logs at 20-30cm intervals or stack them in a crib. Keep blocks a hand's width apart so they never touch
Watering
Humidity is the whole job. Mist once or twice a day when surfaces dry, and cut back during the rainy season
Feeding
No feeding. The nutrition is already in the log or the block
Harvest
Twist the base off once the ear has opened out and the margin ripples. From summer into autumn it flushes again after every rain. Pick before it gets oversized, or it turns tough

What makes the difference. Inoculate in March or April. Cut oak of about 10cm diameter, let it lie a month, then drill and drive in the spawn; the first real flush comes the following year, not that summer. Beginners do better buying a colonised block and learning humidity first

Why this one is harder. Competing moulds are the hard part. Once blue or black mould spreads over the log surface, no wood ear will come. Sterilise tools and hands at inoculation, keep the log itself off wet ground, and raise only the air humidity

Common problems

  • Green mould (Trichoderma) You will see Blue-green powder spreading across the log or block surface What to do Cut out the affected area and take it off site, then space the rest for airflow. Write off a badly colonised log
  • Fungus gnats You will see Small flies gathering, with white larvae under the fruiting bodies What to do Put up yellow sticky traps and discard damaged mushrooms. Clear fallen debris from around the substrate
  • Slugs You will see Chunks torn from the edges of young fruiting bodies, with silvery trails What to do Turn over the supports and pick them off, and raise logs on bricks so they never touch soil

This page describes how a crop is grown and used. It does not claim health effects for any food, nor is it intended to prevent or treat disease. Component and study notes are references only and do not mean the same result occurs in people. Consult a medical professional about health concerns.

Health Benefits

The Donguibogam record — nature, names and the five mushroom woods. The Donguibogam lists wood ear in the Vegetable section as 木耳, with the Korean name of the period alongside. It gives the mushroom a cold nature, called neutral by some, a sweet taste and no toxicity. It divides the names, 菌 for what grows from the ground and 檽, also 蕈, for what grows on wood, and warns that mushrooms from remote mountain spots are often toxic and kill people. It groups elm, willow, mulberry, pagoda tree and paper mulberry as the five mushroom woods and records a method: boil gruel, lay it over the wood, cover with grass, and mushrooms come up, the tender ones being picked and pickled. This is an old medical record and differs from modern medical judgement.

Compositional change during drying. Analyses across several mushroom species report that ergosterol converts to vitamin D2 under ultraviolet light. The same work found large differences in the figure for identical material depending on how it was dried. This concerns a change in composition and nothing should be read past it.

Nutrition

  • Dietary fibre (reported above 50g per 100g, dried) — insoluble and soluble fibre that holds water
  • Beta-glucan (a polysaccharide of the fungal cell wall) — structural cell-wall polysaccharide
  • Ergosterol (partly converts to vitamin D2 when sun-dried) — a precursor of vitamin D
  • Iron and calcium (high as a share of dried weight) — minerals

How long and how cold to soak, and how much it swells Dried wood ear swells five or six times over in water. Fibre is a high share of the dried weight, which is why the bite survives soaking. About 5g dried is one serving. First-time cooks misjudge this constantly and soak far too much, so soak only what the day's dish needs and keep the soak short. If it has to stand overnight, soak it in the refrigerator rather than at room temperature. Anything left out for hours, or gone slimy or sour-smelling, cannot be rescued by cooking and belongs in the bin.

Ergosterol and vitamin D2 Fungal cell walls contain ergosterol, and analyses across several mushroom species report that ultraviolet light converts part of it to vitamin D2. Drying in sun rather than shade has been reported to raise the figure. That is the reason behind the habit of spreading shop-bought dried wood ear in the sun for half a day before cooking. A record of compositional change is as far as this entry goes.

Minerals and which weight is meant Dried wood ear measures high in iron and calcium as a share of its weight. What actually reaches the plate is the rehydrated weight, so comparing dried-basis figures directly overstates the case. A meal uses 5-10g dried. When reading a composition table, check first whether it is quoting dried or soaked.

Pairings

○ Fried in oil — For japchae or fried rice, give it a turn in hot oil first so the water goes off and flavour sticks. Wood ear is mild on its own, and oil and soy sauce fill the gap. Add it late; long frying turns it tough.

○ Egg — Shredded wood ear stirred through scrambled egg is a long-standing pairing. Soft egg against a springy mushroom is the whole point. Shake the soaking water off first or the egg goes watery.

○ Cucumber and vinegar — Blanch it and dress it with cucumber and vinegar. The acid cuts the slippery quality. Rinse in cold water after blanching so the salad does not go slack. Cucumber

△ Do not leave soaked wood ear standing at room temperature — Soak only what the day's dish needs, and keep the soak short. If it has to stand overnight, soak it in the refrigerator rather than on the counter. Wood ear left submerged for hours at room temperature grows bacteria, and the toxin formed there is heat-stable, so boiling or frying will not remove it. Anything slimy or sour-smelling is not rinsed and reused; the whole batch goes out. One serving is about 5g dried, so do not soak a large quantity to be used across several days.

Varieties

  • Black wood ear (spawn) — Thin, translucent, dark brown. Older sources file it under Auricularia auricula-judae
  • Hairy wood ear (spawn) — Short hairs on the outer face and a thicker body. Chewier
  • White fungus (snow ear) (spawn) — A different genus. Translucent white, split into frilled lobes

Source: Donguibogam, Vegetable Section 木耳 · Rural Development Administration (Nongsaro) · Korean Food Composition Table