Feasting on fungi
Beyond the greengrocer’s shelves lies a galaxy of wild mushrooms to thrill the taste-buds of the discerning collector. But spotting the safe varieties is a fine art, and indiscriminate gatherers risk indigestion… or worse. Stephen Brightwell, a relative of the first commercial mushroom growers in New Zealand, separates the dainties from the deadlies, and delves into the history of mushroom collecting in this country.
While human attention (both gastronomic and otherwise) has focused primarily on plants and animals during most of our history, lower orders of life, particularly fungi, have also had a part to play. Our daily bread would not have been leavened without yeast fungi, and alcohol in its various manifestations would still be sugar and water but for a fungal presence.
World War One soldiers nailed bits of fungus-infested wood to their helmets and bayonets. The phosphorescent fungi, glowing faintly in the dark, provided enough light to enable the soldiers to avoid collisions in the trenches, but not enough to make them targets for the enemy.
Another fungus, Penicillium notatum, has saved the lives of many millions of people worldwide: the antibiotic penicillin, named for the fungus that produces it. is one of the foundations of modern medicine.
Mind you, the fungal contribution has not always been benign. Moulds, mildews, rusts and smuts have cast a long and destructive shadow over human endeavour, blighting crops, smiting livestock and visiting disease and death on humankind. To cite just two examples: the great potato famine of 1845 was the work of the fungus Phytophthora infestans, and every year New Zealand farmers have to contend with Pithomyces chart-arum, the fungus which causes facial eczema in sheep and other stock.
But these are seldom the things we think of when fungi are mentioned. For most of us, the word brings to mind mushrooms and toadstools—one lot good to eat, the other deadly. The gathering of field mushrooms from farmers’ paddocks is part of the New Zealand rustic tradition, but equally traditional is the suspicion that goes with anything that doesn’t look like a “normal” mushroom. Most of us wouldn’t give exotic species a second thought—except to bowl them over with a stray foot—let alone see them as something to titillate the taste-buds. Still fewer of us would have considered making a living from fungi.
But the harvesting of fungi has been an important commercial enterprise in New Zealand for over a century, and in some parts of the country the debt owed to this humble life form is considerable.
As early as 1872, New Zealand had a fungus-based industry earning thousands of pounds annually in export returns. The product itself was a most unlikely trading item. Gelatinous, greyish brown and about the size and shape of a human ear, it had the botanical name Hirneola (now Auricularia) polytricha and was known as wood ear, ear fungus or (incorrectly) as Jew’s ear—a name which belongs to its northern hemisphere relative Auricularia auriculajudae. (The name Jew’s ear itself is a corruption of Judas’s ear, given to the fungus because in Europe it is commonly found on elder trees—the species on which Judas Iscariot is supposed to have hanged himself.)
The New Zealand species can be found growing plentifully on the dead trunks and branches of mahoe, pukatea, tawa and other trees of lowland forest areas.
The wood ear trade that was to grow to considerable proportions began as something of a lucky accident. A Chinese trader named Chew Chong had arrived in Taranaki in 1868 with the intention of starting a butter-exporting business. When his early attempts failed, he turned to an idea he had had earlier: exporting edible fungus to his native China.
Chong had noticed the wood ear fungus on fallen trees around the properties of farmers he visited while trying to establish his butter enterprise, and thought it similar to one which had been cultivated on oak stakes in his home country since 300 BC. He sent some samples home to find out if the new variety was edible, and therefore likely to find a market with his people. The response was positive.
By 1871, the trade in wood ear was booming. Its use, according to the then Colonial Secretary of Hong Kong in answer to an inquiry from the New Zealand Colonial Secretary, was as a medicine, for which it was “much prized by the Chinese community.” It was also used as a food, particularly on fast days as a substitute for animal products. On these occasions “mu-erh,” as it is known to the Chinese, was eaten with a mixture of vermicelli and bean curd. It was, and still is, eaten at other times as well, mainly in soups.
In New Zealand, wood ear was eaten by the Māori, who called it “hakeke” (the most common of several recorded names). Unlike the Chinese, however, the Māori did not find much to recommend in the insipid flavour and curious texture (a bit like tender bacon rind), and ate it only when better food was in short supply.
The burgeoning wood ear industry was greatly spurred by the fact that Chong offered the colonial farmers hard cash: fourpence per pound of dried fungus—and this at a time when most other business was done by barter.
To desperate farmers trying to rebuild after the ravages of the Taranaki war, wood ear was a godsend. A substance of no apparent value was suddenly an important source of cash income—literally money growing on trees. With such a lucrative income there for the taking, gathering of fungus became almost a full-time occupation for some families. Soon, cartloads of the fungus, by now known somewhat facetiously as “Taranaki wool,” were making their way to market, having been picked and dried from the branches of the trees felled to make way for new farmland.
It was not always easy money, though, as Reeve Youngman reminisced in his autobiography Perhapsies: Early days in Otago and Taranaki.
“I would pick as much as I could carry home in a sugar sack and thought always how much money I was going to get, and always there was the same disappointment. After spending days sun-drying it thoroughly (it would not be accepted otherwise) it would shrink to about a quarter of its original bulk and a fraction of its weight. As we only received fourpence per pound for it, it was necessary to pick large quantities of the fungus to become ‘rich’.”
Once the commercial value of the fungus became widely known, other traders and communities moved into the business. For the Bohemian settlers of Puhoi, north of Auckland, the industry was all that saved them from starvation at a time when no other means of income were available. Not that they got off to a good start: at first they mistakenly collected bracket fungi—hard, woody growths that are far from edible. However, within a short time the collection of large quantities of wood ear had started, and earnings from the enterprise were sufficient to see the community become, if not prosperous, at least far from the clutches of poverty.
By the early 1880s, many tons of dried wood ear were being handled by Taranaki merchants. Chew Chong alone is said to have purchased an average of 65 pounds’ sterling worth on each New Plymouth market day, while his Eltham and Inglewood stores probably took similar amounts. It has been said that the value of the fungus traded through Chong’s New Plymouth store in 1885 was higher than that of butter for the whole Taranaki province. Chong’s export receipts for that one year have widely been reported as some £70,000—an optimistic figure given that the official export value of fungus from the whole of the dominion was only £11,095.
Some traders were less scrupulous than Chong in their dealings with collectors, and prices as low as a penny a pound were paid by agents working on a five per cent commission. The retail price in the Hong Kong market was a whopping ten-and-a-half pence per pound—a mark up of over 1000 per cent!
The trade in wood ear was maintained by the Bohemians in Puhoi until at least the 1950s, but in Taranaki the industry had begun winding down much earlier. Chew Chong retired from business in 1900, by which time his 1868 dream of setting up a butter factory and making dairy farming profitable in the region had been realised. Ironically, by promoting dairying, he had gradually turned the fungus collectors into farmers. Chong, the instigator of the trade, was also largely responsible for its demise.
When he died (aged 92) in October 1920, Chew Chong was an honoured member of the community and a wealthy man—the value of his fungus exports between 1872 and 1902 had been over £300,000.
“Fungus” continued to be listed as an export item in New Zealand’s annual statistics until at least 1980. As late as 1965, there were still those hopeful of restoring the industry to its former glory, and advertisements placed by agents wanting to buy wood ear were common in the daily newspapers. But by then the heyday of the industry was over.
The final nail in the industry’s coffin came in the late 1960s when methods of cultivating Auricularia commercially on sawdust were developed in Taiwan. Mass cultivation of the fungus made collection from natural sources uncompetitive. Today, the wood ear fungus once exported by the ton is imported and sold through Asian speciality shops to a generation of New Zealanders unaware of the significant influence this wrinkled grey-brown fungus had on the lives of their forebears.
The common commercial mushroom mushroom, Agaricus bisporus, the white button mushroom, has been cultivated in Europe since the time of Napoleon using two basic processes: making spawn and making compost. Today, the annual world production of button mushrooms is 1.5 million tonnes, with the United States the leading producer.
Originally collected from cart tracks and other places where mushrooms grew, button mushroom spawn is now grown in the laboratory by tissue culturing. This process involves taking a small piece from a selected mushroom and, under sterile conditions, incubating it in a dish with nutrient agar.
When the white, hair-like mycelium (the feeding part of the fungus) has covered the dish, it is transferred into the spawn substrate—usually a mixture of grain and nutrients. The inoculated substrate is then kept in warm, moist conditions until the mycelium has spread right through it. At this point it is ready to spawn into beds of compost.
The second process, compost making, is the key to successful mushroom growing. Compost, the food on which the mushroom lives, is made by combining various amounts of straw, chicken manure, horse manure and other organic materials such as maize stalks or coffee beans (which provide extra carbohydrate for the growing fungus), together with gypsum and large quantities of water, and piling it all into a heap.
Within a few hours the bacterial activity will have heated the heap to more than 70°C. After a week, the pile is turned, left for a further week, then turned again. Three weeks after the process begins, it is ready for use.
The compost is loaded into growing beds and pasteurised by allowing its natural heat to raise the room temperature to 60°C, then maintaining that temperature for up to 12 hours using steam. Pasteurisation (or peak heating, as it is known in the industry) destroys any pests which might be present. The beds are then allowed to cool to around 25°C, whereupon they are spawned.
Spawning introduces the mushroom mycelium (usually in the form of fungus-coated barley) into the compost, where it grows, filling the compost bed after 10-14 days. Either at spawning, or a week or so later, the compost is “cased” with a layer of peaty soil which provides a moist support medium for the growing mushrooms. Between 21 and 28 days after spawning, the first flush of buttons is ready for picking.
Growers expect to harvest between three and five flushes from each spawning cycle, with a total yield of around 25 kilograms per square metre of growing tray. After the final pick (seven to ten weeks after spawning) the compost is spent, and the whole cycle begins again.
In New Zealand, the first attempts to grow mushrooms on a commercial scale were made in the 1930s. In 1935, brothers Ormond and Earle Brightwell started growing button mushrooms in the Auckland suburb of Avondale. Their shed had double-skinned walls lined with pumice, and was heated by a coal-fired cast-iron boiler. Compost was made in a separate building from stable manure and straw obtained from the nearby Avondale racecourse. The spawn, imported from British mushrooming pioneers William Darlington and Sons of Sussex, was crumbled over the beds by hand.
By modern standards, the Brightwells’ method of spawning was not very reliable, as Ormond’s son Tom recalls: “Three of them worked their way down the shed, covering about four feet of the bed at a time, and staying in the same order. When the mushrooms came through there was one section with practically none on it, repeated down the length of the shed. They never did find out who had the evil touch.”
Such setbacks were commonplace in the early days of the industry, but efforts to establish viable mushroom farms continued. with major breakthroughs coming at regular intervals. In 1937, the benefits of using gypsum (calcium sulphate) in the preparation of compost were established. The gypsum stopped the compost from becoming waterlogged and “puggy,” and with its introduction large crops could be grown reliably for the first time.
The introduction of formalin a couple of years later—for sterilising the mushroom boxes and sheds—was likewise a huge step forward, greatly reducing the ravages of pests and diseases. By the mid-1960s, both the cultivation technology and the spawn quality had reached a state where the industry could consistently produce high crop yields.
For the Brightwells, the developments came too late: the mushroom house was torn down in 1951 to make way for hothouse tomatoes. But there were plenty of other growers to take their place, and by the 1960s the infant mushroom industry was enjoying rapid growth. The number of growers climbed steadily until 1975, when an unusually long, warm autumn gave a very long field mushroom season. The good news for mushroom gatherers was bad news for growers, and as many as half were forced to shut down their operations.
That one tough autumn left only about 20 growers still in business in 1977. Between them, they produced 1715 tonnes for the year. But, if the industry had suffered a blow, it was down, not out. At the turn of the 1980s, production had increased to 2936 tonnes—an increase of more than 70 per cent in only five years—and the number of growers remained virtually unchanged. Today, there are still only about 20 commercial button mushroom growers in New Zealand, although total production has further increased—to around 7000 tonnes.
Through selective breeding, the cultivated button mushroom Agaricus bisporus has, over the last 350 years, become thoroughly domesticated. Once found wild in Europe—like its close relative A. campestris, the common field mushroom—it has been genetically improved to meet the requirements of cultivation. Chief among these qualities are its long fruiting (mushroom-producing) period. Unlike the field mushroom, which grows slowly, then fruits and dies rapidly, A. bisporus has the rapid growth and long production period essential for commercial cropping.
A second Agaricus species, A. bitorquis, is also grown commercially, though less commonly. It is not susceptible to the mushroom viruses which can devastate A. bisporus crops, and tolerates temperatures higher than those withstood by A. bisporus. For these reasons, a grower will sometimes switch to A. bitorquis if there has been a problem with virus strike, or if high summer temperatures make cooling of growing sheds necessary for the economic production of A. bisporus.
Despite these apparent advantages, A. bitorquis is not a preferred cultivar, as its slightly tougher texture and more robust appearance do not find favour with consumers.
In these market-driven times, the customer’s wish is the grower’s command. And what the customer wants, says Roger Giles, managing director of New Zealand’s largest mushroom producer, Meadow Mushrooms, is clean white caps about 40 mm across, with no blotches on top and no gills showing.
Meadow Mushrooms, based in Christchurch, harvests some 84 tonnes of mushrooms per week, three-quarters of which end up on the domestic retail market, while the rest is either exported or canned.
At Meadow Mushrooms, compost is made by the hundred tonne using earthmoving equipment. It is turned by machine and spawned by machine. The growing trays are stacked four- or five-high in enormous air-conditioned sheds, and harvesting occurs seven days a week.
Eight hundred kilometres away, at Limburgia Gardens, near Hamilton, the scale of operations is much more modest. Jacob Van Selm and his sons grow their mushrooms in plastic bags which are filled by hand and spawned by hand. The bags can be easily lifted and stacked by one person, obviating any need for special lifting equipment.
Van Selm admits his method is labour intensive, but with his sons also working in the market garden, labour is not something he is short of. He says that, for the same reason, this method of growing has become popular in Ireland, where co-operative ventures share both facilities and manpower.
The plastic bag method also allows the grower to isolate part of his crop, should it become infected, without losing the production that shutting down a larger bed would entail. And at the end of the cycle there is the advantage that the compost is ready-bagged for sale to the public as garden compost.
Positioned somewhere between Meadow’s mass-production and Limburgia’s “mushrooms-by-hand” is the small but high-tech operation of Franz Van Schie, also near Hamilton. In an upstairs office overlooking his growing sheds, Van Schie, a former refrigeration engineer, sits at a computer keyboard and monitors the microclimate of his mushrooms.
With the jab of a key. Van Schie can adjust the temperature, humidity, amount of ventilation and oxygen and carbon dioxide levels of hi, sheds. Precise control of these parameters is, he believes, the key to obtaining consistently high yields.
For example, it is important to keep the growing trays in an environment of 3 – 5 per cent carbon dioxide and 80 – 90 per cent humidity for the first ten days after spawning. These conditions promote the growth of the mycelium, but inhibit the production of mushrooms. After this period, oxygen levels are increased by ventilating the sheds; this triggers mushroom production.
As well as maximising production, precise control of the growing environment reduces the threat of pest and disease attack—a potential nightmare for any primary producer. “I harvest seven tonnes of mushrooms per shed per crop, and I get between four and five dollars a kilo,” says Van Schie. “If I were to lose a single crop to disease, that would be a year’s salary down the drain.”
Disease is not the only concern for today’s mushroom farmer. Environmental issues loom increasingly large on the horizons of many growers. Making compost is a messy and malodorous business, and residents living near mushroom farms are none too thrilled about smelling compost day in and day out. Large amounts of water are used in the composting process, and under the new resource management regime that water cannot simply be flushed into the nearest creek.
Franz Van Schie’s solution to these problems has been to design a water purification and recirculation system which enables waste water to be reused on the next compost stack, and to pass waste air through a biofilter which traps organic matter and thus reduces the smell.
Roger Giles of Meadow Mushrooms is redesigning his composting operation to allow the stacks to be aerated from beneath. Increasing the oxygen level in the compost keeps the level of smelly sulphides down, but too much oxygen will push up the temperature of the stack to 80°C and kill the bacteria and fungi which make the compost. Giles’s research indicates that about one per cent oxygen is the right amount for a two-metre by two-metre stack.
So, while for a few family-run farms like the Van Selms’, low-tech is proving a viable approach, for many larger operations the move to a more high-tech style of cultivation seems inevitable.
Although agaricus bisporus dominates the New Zealand mushroom scene, this is by no means the case internationally. In China, for example, button mushrooms account for less than 10 per cent of total mushroom production. Worldwide, four million tonnes of mushrooms are produced, but only 1.5 million tonnes are buttons; the rest are speciality or exotic mushrooms, grown either for culinary or medicinal use .
In New Zealand, the only speciality mushroom grown in any quantity is shiitake (Lentinus edodes).
Initially, this fungus got off to a boom start in 1985 when the company Greenfields set up a large operation in Auckland using Singaporean technology and Development Finance Corporation funding.
Production soon reached an impressive seven tonnes per week, but the collapse of the DFC put an end to the venture.
Subsequent interest in shiitake has been slow to build up again, according to Lance Jones of Ju Lin Shiitake in Hamilton—the main commercial supplier of shiitake, with a production of 250 – 350 kg per week.
In their wild state, shiitake grow on rotting logs. In the commercial arena, the “logs” are usually artificial—a mixture of sawdust and nutrients—and the growing process is much faster.
The sawdust base (Ju Lin uses tawa) is first packed into long narrow plastic bags before being steam sterilised for several hours. The logs are then inoculated under conditions described as being “similar to those of an operating theatre.”
The reason for such great care is that it will be three months before the mushrooms appear—ample time for any faster-growing competitors which may be present to gain the upper hand. As the shiitake mycelium spreads through the sawdust it will turn the log first white, then chocolate brown—an indication that fruiting is about to begin.
The average yield, compared to button mushrooms, is low—around 250 grams per kilogram of log, spread over an 8- to 10-week period. The market price compensates: at $16 20 per kilogram, the return to the grower is four times that of button mushrooms. Even so, demand is only moderate, and Ju Lin faces an uphill battle to win local acceptance for the newcomer.
One potentially strong point in shiitake’s favour is its proven medicinal value. Lance Jones’s quip, “a shiitake a day keeps the doctor away” has sound support in the medical literature. Shiitake has been found to strengthen the immune system, and is used in Asia to cure viral hepatitis, and as a dietary supplement in the treatment of tumours.
The fungus industry in New Zealand has come a long way since its humble beginnings with Chew Chong’s accidental discovery in Taranaki in 1868. Button mushroom production continues to increase, and some speciality mushrooms are poised to make their grand debut.
The shiitake growers, now supplying a tiny local market, are looking to Asia to sell their increasing production. In so doing they are retracing the path to the Oriental markets Chew Chong pioneered more than 120 years ago. The wheel has turned full circle, and New Zealand-grown fungus is once again finding its way to the markets of Asia. Chew would be proud.
“Cloudberry knew that there were other fungi, wicked poisonous fungi, and some had quite a nice taste. Why not find some Fly Agaric or, better still, Death Cap, that innocent looking white toadstool which grew in waste places? He could mix them in with the edible fungi and make an appetising brew! The gnomes were always bringing back mushrooms and other fungi for the pot. He could poison off the lot . . . and then he would have the distinction of being the last gnome in the whole of Britain!”
In the language of flowers, the mushroom means suspicion—and with Cloudberry’s style of mischief fairly common in English literature, it is little wonder. People of Anglo-Saxon descent, it seems, trust only the common mushroom, and have “fungophobia” about the rest.
Other cultures have a vastly different attitude, and in France, Italy and other European countries, wild fungi are a coveted culinary item. In autumn, wild mushroom gathering becomes so popular that the French convert their pharmacies into mushroom identification centres, and pharmacists offer expert opinion so that the carefully collected specimens can be consigned to the menu without fear.
One European text devoted to mycophagy (fungus eating) gives over 100 recipes for more than 20 species of fungi, ranging from the inexpensive button mushroom to the highly prized truffle. No edible fungus is allowed to escape the dinner plate.
New Zealand mycophagists must adopt a more do-it-yourself attitude. There is only a limited amount of information available on local fungi, so identifying even the better known edible species can be a trial of nerves at first. This caution is not unreasonable: we have a number of fungi which are seriously toxic, and some which are deadly. It pays to learn what they are before it’s too late.
Public enemy number one is the death cap, Amanita phalloides, which overseas has killed whole families, and on one tragic occasion led to the death of 31 children at a camp when it was included in a meal. Less than one teaspoonful can kill an adult, and it is especially dangerous because the first symptoms of poisoning (vomiting and diarrhoea) do not show up until between 6 and 24 hours after the fungus has been eaten. By then, the toxins are in the blood‑
stream, and treatment with laxatives or emetics is of little avail.
Amanita poisoning is further complicated by the fact that victims may appear to recover, and then suddenly deteriorate several hours later. In at least 50 per cent of cases, victims die of liver and kidney failure within three to ten days of eating the mushroom, and there is no known antidote.
At first glance, the death cap may look similar to a field mushroom—hence its potential danger to careless collectors. However, even casual inspection reveals key differences: the death cap’s gills are white while the field mushroom’s gills are pink, turning brown and finally black with age; field mushrooms have a clean stalk of uniform thickness while the base of the death cap’s stalk is swollen and bulb-shaped and has a pronounced collar of skin called the volva. Death caps are usually found around oak trees, while the field mushroom is usually an inhabitant of more open pasture. There are no recorded New Zealand deaths from this mushroom.
Closely related to the death cap, but less toxic, is Amanita muscaria, fly
agaric-so named because it was once used as an insecticide. Fly agaric is the classic fairytale toadstool, and with its white stem and bright red cap sprinkled with white chips it is unmistakable. Although it is not deadly, it should be regarded as a seriously toxic mushroom, its consumption often resulting in delirium and disturbed vision and speech.
Both Amanita species are relatively recent arrivals to New Zealand. They were probably introduced by chance from Europe some time in the last century on the roots of the trees with which they associate. By contrast, the “magic mushroom” (Psilocybe cyanescens) is said to have been introduced deliberately from Australia or North America in the 1960s by promoters of the hippie culture. (Under New Zealand law, the magic mushroom is a prohibited substance, and possession of the fungus or chemical derivatives from it is a criminal offence.)
Apart from these notorious species, most New Zealand fungi are of unknown toxicity, and the main edible mushrooms are, if not the same species, then closely related to those found and enjoyed in Europe. They are generally easily identified, and, provided basic rules of identification and sampling are followed, can be safely included in meals, where they will be both a flavoursome treat and a conversation starter. Indeed, some are so superior in flavour to the common supermarket mushroom that those appreciative of fine food will wonder how they did without them for so long.
Shaggy ink cap (lawyer’s wig, shaggy mane)
With its tall busby-like cap which falls in shaggy layers as it matures, the shaggy ink cap is a distinctive mushroom with a delicious flavour. Look for it on pastures, lawns, and particularly along road sides in late summer and autumn. It grows to about 15 cm in height and has a prominent ring on its stem. The gills are white when young, turning pink and then black with age.
Shaggy ink caps burst out of the ground with considerable force: on occasions, they have pushed their way up through asphalt tennis courts. One specimen is reported to have “lifted a ten-pound slab of concrete in a heroic attempt to proliferate its species.”
These Herculean tendencies are short-lived: the whole mushroom decays rapidly after collection, ultimately dissolving into an inky mass, so eat it on the same day that you collect it.
A word of warning: the closely related species Coprinus atramentarius, known as “tippler’s bane,” produces unpleasant side effects if consumed with alcohol, but no such symptoms are known to arise when shaggy ink caps are accompanied with alcohol.
Horse mushrooms look much like giant field mushrooms, and are found in similar open field locations in autumn. The large size (up to 30 cm) makes them hard to miss, and, like most mushrooms, once located, they can usually be found in the same place in subsequent seasons.
Horse mushrooms have a prominent ring on the stem, and the gills start out whitish (take care with identification; many white-gilled fungi are inedible), turning grey and then dark brown as the mushroom ages. The taste is similar, but slightly woodier, than the field mushroom.
Pine bolete (slippery Jack, sticky bun)
Suillus granulatus and S. luteus
Members of the same family as the cape or porcini of French and Italian culinary fame respectively, pine boletes are found in abundance under pines throughout New Zealand, and are easily identified by the fact that they have pores instead of gills on the underside of the cap.
Pine boletes are found in autumn and early winter, grow up to 25 cm across and, when young, are lemon-yellow underneath and leather-brown on top. They have a distinctive sticky coating of slime on the upper surface. S. granulatus differs from S. luteus in having no ring on the stalk, having a more orange colour and having a number of glandular dots around the upper part of the stalk.
Pine boletes should be tasted when raw, and any which are bitter or peppery should be discarded, as should any which show redness or blueness around the pores. Older specimens have fawn- to golden-coloured pores and are past their gastronomic prime.
Pine boletes (and the related birch bolete, common under silver birch trees) have good flavour, but they retain a slightly slimy texture when cooked. On this attribute, the American fungal writer David Arora comments that “one novel solution is to take advantage of their inherent wetness by using them as an escargot substitute. (You can boil them, flavour them with herbs, stuff them into empty snail shells and call it ‘Parsley, Sage, Rosemary and Slime!’)”
Morels are highly distinctive mushrooms with deeply pitted fawn- or brown-coloured heads and white stems. They are not common, but in spring and early summer look for them in fruit orchards or around bush clearings where there have been campers’ fires. Morels should be cut lengthwise to check that they have an empty chamber running through the stem and into the head. A solid chamber may indicate that a specimen is a poisonous brain mushroom of the Gyromitra genus.
The strong flavour of morels is highly regarded by mushroom connoisseurs, but neophytes may find them more palatable as flavourings in soups and stews.
Langermannia (Calvatia) gigantea
On rare occasions, giant puffballs can grow up to a metre in diameter, but are typically smaller—somewhere between a softball and a volley ball in size. On the outside, they are white or cream-coloured. Inside, the flesh is white when young; any other coloration (usually fawn to brown) means that the specimen is too ripe and cannot be eaten.
Giant puffballs are found in pastures—large ones have been mistaken for sheep!—along roadsides and in gardens in late summer and autumn. They can be eaten both raw or cooked. Raw, they are similar to an unripe Camembert cheese in both flavour and texture, and are good in salads. Cooked, they have a mild flavour not unlike a cultivated button mushroom.
Wood ear resembles thin human ears and grows on dying or dead trees, especially softwoods such as mahoe. The outer surface is dark brown; the inner surface is pinky grey. Wood ear is very popular in Asian cuisine, and if you cannot find fresh specimens in the wild, the fungus can be purchased in a dried state from most Asian speciality stores, and then reconstituted in water. Wood ear has little real flavour, but imparts an excellent chewy texture to your stir-fry.
On the Fungal Horizon
They have been described as a cross between a shrivelled human brain and a lump of coal. They have more in common with peach brown rot than with gilled mushrooms, but they are worth almost their weight in gold, and several New Zealanders are trying to grow them.
They are truffles—those ugly wart-encrusted lumps of fungal flesh which possess, in Gerald Durrell’s words, “the scent of a million autumnal forests,” and the very mention of which causes gourmets the world over to drool.
New Zealand truffles? Est-ce que c’est possible? Certainly, if several years of painstaking work by Ian Hall and his colleagues at Crop and Food Research (formerly MAFTech) at Invermay, near Mosgiel, yields its expected results.
Hall and his team have been looking primarily at mycorrhizal species—root fungi which form symbiotic (mutually beneficial) relationships with their host trees—with the focus on those fungi likely to offer lucrative returns, and hence capable of justifying the research investment in dollar terms.
For the Invermay biologists, this means learning how to cultivate gourmet fungi which can be supplied to northern hemisphere markets at times when local fungi are out of season, and prices are correspondingly high.
First among this fungal elite is the Perigord black truffle, Tuber melanosporum, which grows and fruits entirely underground. In its fresh state, it fetches between $1,000 and $9,300 per kilogram on European markets, depending on the quality and supply.
Led by Hall, New Zealand research into truffle production started at Invermay in 1979. Successful inoculation of young trees with the black truffle fungus soon followed, and the first New Zealand grove of fungus-carrying trees was planted in 1987 at Kurow, North Otago.
There are now 20 such groves (known as truffieres) of inoculated hazel and oak trees in the country, from Alexandra to the Bay of Plenty. Some of these plantings have been made on what are considered prime sites and soil types for truffles, while others have required applications of vast quantities of lime—up to 40 tonnes per hectare! The potentially lucrative returns for truffles apparently make the high setting up costs acceptable.
Hall’s research indicates the chances of success are relatively high—but, to date, no New Zealand truffieres have borne fruit. Be patient, argues Hall. “Artificial truffieres in both Spain and Northern California have taken between seven and ten years to start production, and that is consistent with the estimates we have obtained from French sources,” he says.
But there are other indicators which give those who have put their money into the venture reason to be optimistic. “We have already got brides [rings of sparsely vegetated soil around truffle-infected trees),” Hall says, “and the rate of growth of our oak trees, in particular, is faster than that which the Europeans have experienced with their inoculated trees.”
The 1993 season will be the sixth for the first of the truffieres planted. Hopes are high that Boss, New Zealand’s one and only truffle dog (trained in a similar manner to customs drug dogs), will be able to sniff out the first truffles grown in local soil. Says Hall: “When, or if, that happens, we will know a lot more about the progress of the New Zealand truffle enterprise than we do at present.”
While truffles are the major focus of the Invermay research, they are not the sole interest of the research team. Experiments with the Japanese matsutake Tricholoma matsutake—a species which sells for up to $2500 per kilogram in Japan—have shown considerable promise: the fungus has been successfully inoculated on to both its natural mycorrhizal partner Pin us densiflora and on to Pin us radiata. In achieving the latter fostering, the New Zealand research has leapt to the forefront of commercial matsutake development.
But don’t hold your breath waiting for the first indigenous matsutake. Like truffles, they take about 20 years to produce in their natural habitat, and it is likely that they would take at least half that time in artificial plantations.
The difficulty in cultivating truffles and matsutake is that you are dealing with a very delicate relationship between two living organisms: a fungus and a plant. Unlike saprophytic fungi such as button mushrooms and shiitake, which will fruit as long as there is a suitable nutrient source, mycorrhizal species are unpredictable, even in the wild, and this is why they command such high prices. They will never be mass produced, and they will always be seasonal. So, whereas a country like New Zealand could never hope to achieve more than niche market success with saprophytic mushrooms, the country has a real chance of supplying the more temperamental mycorrhizal species, especially given our resources of trees and land.
Behind the matsutake and truffle, in terms of development, are several other edible fungi. Boletus edulis, the cape or penny bun of French cookery, and considered by many to be the king of mushrooms, is being investigated with the assistance of European specialists. Cepes are mycorrhizal on beech, birch, oak and some pines, and the recent discovery of the species growing wild under oaks in Christchurch has pushed this programme forward.
At both Invermay and Canterbury University, a small Japanese puffball known as shoro, Rhizopogon rubescens, is also being studied as a possible export crop. This fungus, which has a fibrous, pinkish flesh, has become rare (and consequently extremely valuable) in its native country. Attempts to inoculate Pinus radiata seedlings with the fungus mycelium have proved successful, and experiments to test the growth rates of inoculated seedlings are now under way.
Local mycologists are also interested in oyster or abalone mushrooms, which rank second to the button mushroom in worldwide production, having recently overtaken shiitake. The main cultivated species, Pleurotus ostreatus, has been outlawed in New Zealand because it has been recorded overseas as a pathogen of pine trees, and it is feared that its introduction commercially could put valuable pine plantations at risk.
Although P ostreatus is currently off-limits to growers, it may be that New Zealand possesses an endemic species which would satisfy commercial and culinary requirements.
The task of identifying local pleurotes is being led by Peter Buchanan and Barbara Segedin of Landcare Research (formerly DSIR) in Auckland. Pleurotus opuntiae, a white-gilled fungus which grows on dead cabbage trees, is known to be edible, as is the darker-topped P. australis, and there may be others.
While the commercial cultivation of highly priced gastronomic fungi is the present goal of current New Zealand research, it is likely that fungal research in future will also be directed towards new ways of feeding the billions of hungry mouths on the planet.
According to Roderick Cooke of Sheffield University, that development will focus on microfungi, specifically the yeasts, which are capable of producing huge quantities of food protein in very short time spans. Yeasts, Cooke claims, are able to synthesize 1000 kilograms of food protein per kilogram of starting mass in a 24-hour period-10,000 times more than soya bean plants and a million times more than beef cattle!
With such astounding productivity, they must one day play a major part in world food production, Cooke argues.
So, whether the crystal ball sees gourmet food for the few or bulk protein for the masses, it looks certain that the place of fungi in the food stakes is assured.