Homiclub
Shiitake
Type
Mushrooms
Difficulty
Easy
Season
Spring·Fall
Sowing
From spawn
Mushrooms

Shiitake

Lentinula edodes

Guanylate, beta-glucan · a mushroom grown on a block

Shiitake is grown by inoculating spawn into oak logs or into pressed sawdust blocks. In a city the sawdust block kit is the common route: kept on a balcony or in a cool room and misted, it pushes caps in around ten days. It dislikes direct sun and dry draughts, so it wants half shade and steady humidity, and a block that has just fruited needs two or three weeks of rest before it is soaked again. Caps picked at home still go into the pan rather than the salad bowl — cook them through, because streaked, whip-like rashes have been reported after eating raw or undercooked shiitake. The Vegetable section of the Donguibogam carries a mushroom entered as 蘑菰, giving it a neutral nature, a sweet taste and no toxicity, and adding that it is very fragrant and good to eat; whether that name stands for shiitake as it is known today is not certain. Picking mushrooms that came up on their own in the woods is a different activity altogether, and this entry covers only shiitake harvested from inoculated logs and blocks.

Where It Grows

ChinaJapanSouth Korea
Main producer Major producer Latitudes at 12–18℃ Zoom and pan to explore · temperatures are rough zonal averages
  • Main producer Produces most of the world's shiitake. Zhejiang, Fujian, Hubei and Henan are the centres, and both log cultivation and sawdust-substrate cultivation are large.
  • Main producer Oita and Miyazaki are the growing areas, and much of the crop is raised on oak logs and sold dried.
  • Major producer Cheongyang and Buyeo in South Chungcheong, and Jangheung in South Jeolla, are the known areas, and the logs used are oaks. Harvest April, May, October, November
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It is a mushroom that grows on the dead wood of oaks in the broadleaf forests of East Asia, including Korea, China and Japan. The method of raising it by driving spawn into cut logs began some 800 years ago around Longquan in Zhejiang, China, and carried on to Japan and Korea; today those three countries account for most of the production. World statistics count mushrooms as a single category, so production figures for shiitake alone are hard to compare country by country. Sawdust-substrate cultivation has also reached the United States, Europe and Southeast Asia, but the scale is small and it is not included here.

Optimum
12~18℃
Range
5~28℃
Hardiness
Not applicable
Day length
Not applicable

The mycelium spreads fastest at 24~27℃, while the caps push up in cooler conditions, 12~18℃. That difference in temperature is why fruiting is concentrated in spring and autumn. Humidity of around 80% is required, so nothing comes up when dry winds persist, and the mycelium inside the log overwinters (passes the winter) as it is.

Harvested 1–2 years after planting. After the spawn is driven into the log, the mycelium takes more than a year to spread, so the first mushrooms appear in the spring or autumn of the following year. The month of inoculation and the month of first fruiting do not fall in the same year. Once a log is established, it produces each spring and autumn for three or four years.

In Korea Nationwide

It is grown throughout the country. The logs are oaks — sawtooth oak, oriental cork oak and konara oak — cut in winter once the leaves have dropped, with spawn driven in during February and March, and the caps come up in spring, in April and May, and in autumn, in October and November. Some are picked wild in the hills, but most of what reaches the market is cultivated.

How to grow

Light
Half shade out of direct sun. Ordinary window brightness is enough; direct sun dries the block out
Soil and depth
Nothing is planted in soil. A pressed sawdust block or an oak log takes the place of the ground
Spacing
Leave 10cm or more between blocks so air moves on all sides. Pushed together, caps press on each other and mould follows
Watering
Mist once or twice a day so the block surface never dries. Aim for roughly 80 percent humidity, and never let water pool
Feeding
No feeding. The block's own nutrients carry two or three flushes, after which it is replaced
Harvest
Pick when the cap is about seven-tenths open and the rim is still curled under. Grip the base and twist so the block is not torn. Once the cap is flat the aroma fades and the flesh thins

What makes the difference. Rest a spent block for two or three weeks with no water, then soak it in cold water for half a day; that soak triggers the next flush

Why this one is harder. Log cultivation is a different undertaking. Fell oak of around 10cm diameter in winter after leaf fall, dry it a month, drive in spawn in February or March, and wait a year or more in the shade while the mycelium runs before the first mushrooms appear. On a balcony both the space and the wait are heavy, which is why block kits are the practical route

Common problems

  • Green mould (Trichoderma) You will see A green, powdery mould spreads across the block surface What to do Take the affected block out and discard it. Wash your hands before handling the rest and bring the humidity down slightly
  • Fungus gnats You will see Small flies around the block and holes at the base of the stems What to do Set yellow sticky traps and screen the vents. Pick off and discard damaged mushrooms
  • Slugs You will see Grazed cap edges and a silver slime trail left overnight What to do Collect them by hand in the evening, and stand the block tray on a water-filled saucer to cut the route up

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

What the Donguibogam records — nature and taste. The Vegetable section of the Donguibogam carries a mushroom entered as 蘑菰. It records a neutral nature, a sweet taste and no toxicity, and adds that the mushroom is very fragrant and good to eat. It is a short entry quoting the Uihak Ipmun. Whether that name stands for what is called shiitake today is not certain. This is a historical medical record and differs from modern medical judgment.

Analyses of ultraviolet ergosterol conversion. Several analyses report that ergosterol in shiitake converts to vitamin D2 on exposure to ultraviolet light. Measurements also report that the amount converted varies with exposure time, exposed surface and how the caps are laid out. This concerns a change in composition and has no bearing on preventing or treating disease.

Taste compounds and drying. Food science analyses report an increase in 5'-GMP during the drying of shiitake. The result is that fresh and dried shiitake differ in their taste-compound profile. This is an analysis of cooking behaviour.

Nutrition

  • Guanylate (5'-GMP) (rises sharply during drying) — a nucleotide behind savoury taste
  • Ergosterol (converts to vitamin D2 under ultraviolet light) — a sterol that is the precursor of vitamin D2
  • Beta-glucans (including lentinan) (structural material of the fruiting body cell wall) — beta-glucan polysaccharides isolated from shiitake
  • Dietary fibre (around 40g per 100g, dried) — largely water-insoluble fibre

Drying and guanylate Analyses report that 5'-GMP rises as drying ruptures the cells. That is why fresh and dried shiitake behave almost like two different ingredients. Rehydrating slowly in cold water loses less aroma than a fast soak in hot. Keep the soaking liquid and use it in the stock rather than pouring it away.

Ergosterol and vitamin D2 Shiitake contains ergosterol, and analyses report that ultraviolet light converts it to vitamin D2. Mushrooms raised entirely indoors see almost none of that conversion. Measurements report higher levels after half a day in the sun with the gills facing upward. This is a record of a compositional change and nothing beyond that.

Beta-glucans and fibre The cell wall of the shiitake fruiting body is built from polysaccharides including beta-glucans, one of which was isolated under the name lentinan. Dried shiitake carries around 40g of dietary fibre per 100g, an order apart from leaf vegetables. Most of it is insoluble, so a large helping at once can sit heavily. This entry stays with the compositional record.

Water content and reading a composition table Fresh shiitake is around 90 percent water, so its energy figure per 100g is low. Drying cuts the weight to about a tenth, and the same 100g then reads completely differently. Check whether a composition table is on a fresh or dried basis before comparing numbers. In the pan, fresh caps release a lot of water, so work them fast over high heat — but cook them through rather than searing the surface alone. That holds for caps just picked at home as well: streaked, whip-like rashes have been reported after eating raw or undercooked shiitake.

Pairings

○ Kelp and anchovy stock — Guanylate from dried shiitake, glutamate from kelp and inosinate from anchovy are three different savoury compounds. Used together they build a deeper stock than any of them alone. Pour in the shiitake soaking water as part of the liquid. Kelp

○ Hard fry in oil — Shiitake holds a lot of water and goes slack over low heat. Oil and a hot pan keep the edges firm and hold the aroma. Slice the caps thick and lay them out without overlapping.

○ Drying in the sun — Half a day in the sun with the gills facing up already changes the aroma and the composition. It is also the way to handle a kit that throws a whole flush at once. Once fully dry, seal them in a container and keep them somewhere cool.

△ Mushrooms picked in the wild — Shiitake here means a cultivated crop. Omphalotus japonicus, the Korean hwagyeong mushroom, grows on wood, resembles shiitake and has caused repeated poisonings in Korea; it is not a difference you can settle from a photograph or a cap colour. Do not pick or eat a wild mushroom you cannot identify with certainty. Everything in this entry applies only to shiitake taken from inoculated logs and blocks.

△ Raw or undercooked caps — Shiitake must be cooked through. A striped, whip-mark rash has been reported in Korea and abroad after eating raw or undercooked shiitake, and the compound responsible is understood to break down with sufficient heat. Avoid slicing it raw into salads or giving it only a brief surface sear. The reaction is uncommon, but cooking it through generally settles the question.

△ A block gone mouldy — If green or black mould spreads across a kit block, discard the block. Shiitake mycelium is white, and once another mould has taken hold it is hard to reverse. Do not eat mushrooms that came from a block with mould running through it.

Varieties

  • Sanjo 701 (spawn) — The widely distributed line for log cultivation. Sets a thick cap
  • Sanjo 708 (spawn) — Bred for sawdust block cultivation. Short flush cycle
  • Hwago (baekhwago, heukhwago) (grade) — Not a cultivar name. It is a grade for caps cracked into a tortoiseshell pattern, which happens in cold, dry conditions
  • Donggo and hyangsin (grade) — Donggo is a thick cap still curled under, hyangsin a fully opened thin one. Again a grade, not a cultivar

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