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Mushrooms
shiitake

Introduction

spores

Magical powers…….
Mushrooms are undoubtedly one of the most remarkable phenomenons of the plant world. They require very little sunlight, do not contain chlorophyll, do not form roots, leaves or blossoms and obtain their food from organic waste.  Unlike other vegetables they are unable to photosynthesis and are therefore not built from cellulose.  They are comprised of chitin, a complex mixture of glucose and amine.  They can suddenly appear from nowhere (or that is how it looks to the naked eye), in what seems like no time. That in itself is amazing, however, there is more.  Since some types of fungi contain materials which can cause hallucinations, or illness or even death, toxic mushrooms have been connected with evil practices by wizards, magicians and poison mixers for centuries.  Despite this, mushrooms, properly identified, have been enjoyed for just as long as food and in certain cases considered delicacies.

Function of mushrooms

Edible mushrooms can be used more or less in two ways; as a main ingredient for example in mushroom ragout or mushroom soup, or as a flavour enhancer for example in morel cream sauce or mushroom risotto.  With the exception of raw mushrooms in salads, they are normally fried, braised, sautéed, or cooked in some other way.  The number of recipes to which include mushrooms are almost too numerous to count as they can be used in every course on the menu with the exception of desserts.  The following are a few examples:

  • Cold starters: salads, terrines, carpaccio, mushrooms à la grecque
  • Clear and bound soups:  mushroom consommé, cream of mushroom soup
  • Warm starters: mushroom pasties, mushrooms on toast, filled mushrooms, mushroom gratin, mushroom beignets, mushroom risotto, mushroom quiche
  • Main courses with meat: steak with mushrooms, veal in mushroom sauce, blanquette of veal or lamb
  • Main courses with poultry: chicken fillet filled with duxelle of mushrooms, chicken in morel cream sauce, poultry ragout, coq au vin
  • Garnish with fish, meat, poultry and game: mushroom ragout, sautéed mushrooms
stuffed mushrooms

The nutritional value of mushrooms

Mushrooms are comprised of 90% water. Naturally they contain nutrients, of which proteins and carbohydrates (both roughly 4%), are the most important.  As well as this they contain minerals such as phosphorus, vitamins such as niacin and vitamin C and a reasonable amount of fibre, depending on the type. Mushrooms have a fat content of less than 1%, therefore contain few calories. On average they contain 30 Kcal per 100 gram.
Since they can have a full flavour and meaty texture they are often used in vegetarian dishes.  For vegetarians they are not seen as a good substitute for meat as the protein content is too low (only 3 or 4% compared to meat which is 20%).  Since they contain few calories, they are very suitable for use in diets with a low fat content.

Purchasing mushrooms

When mushrooms are purchased, the following points should be taken into consideration:

  1. The types of mushrooms available
  2. Their condition
  3. Their quality
  4. The price
  1. The types of mushrooms available

Mushrooms can be classified in various ways:

    1. According to their origin
    2. According to their form
    3. According to their type and appearance
  1. according to their origin

Originally all mushrooms were found in the wild.  Nowadays certain species are cultivated on a very large scale. The most important advantage of this is that they are available all year round compared to wild mushrooms that are only available at certain times of the year.  It must be noted that cultivated mushrooms have far less flavour and aroma than mushrooms that grow in woods, forests or fields.

The assortment of cultivated mushrooms is growing all the time – nowadays more unusual types of mushrooms are cultivated compared to even a few years ago and this trend is expected to continue in the future.
As far as the preparation of mushrooms is concerned, it makes no difference if they are wild or cultivated.  There is a big difference in the price however and this may be the biggest influence on deciding which ones to buy for the various dishes on the menu.

mushrooms cultivated wild mushroom
  1. According to their form

There is a lot of difference between fresh, dried and those mushrooms preserved in liquid. Since dried mushrooms have their moisture removed, the flavour and aroma are much more concentrated.  Dried morels and boletes have therefore a much stronger flavour and aroma than the fresh varieties.  When mushrooms are preserved in tins or pots, the (preserving) cooking liquid absorbs much of their flavour.

dried mushrooms fresh mushrooms
  1. According to their type

There are more than 40,000 differed types of known mushrooms.  Even in a small country like Holland there are over 4,000 types. From a biological point of view mushrooms are categorised according to the way the spores are produced. In the following sections more information will be given.  Since practically all mushrooms are cleaned and prepared in the same way, the biological categorisation is not important in the kitchen.
The following chart shows a sample of various mushrooms and the physical condition in which they can be purchased.


Mushroom

Wild

Cultivated

Fresh

Dried

Tins/pots

Bolete

*

 

*

*

*

Puff balls

*

 

*

 

 

Chantarelle

*

 

*

*

*

Button or common white

 

*

*

*

*

Enokitake or Japanese

*

*

*

 

 

Hedgehog or Hydnum

*

 

*

*

 

Honey or Armillaria

*

 

*

 

 

Craterellus

*

 

*

 

 

Milky cap

*

 

*

 

 

Morel

*

 

*

*

 

Oyster

*

*

*

 

 

Bearded or monkey

 

*

*

 

 

Fairy ring

*

 

*

 

 

Shiitake

 

*

*

*

 

Truffle

*

 

*

 

*

Fairy ring

*

 

*

*

 

 

 

 

 

 

 

chanterelles

2. The physical condition
The following categories can be formed depending on the physical condition of the mushrooms:

      1. Fresh mushrooms
      2. Dried mushrooms
      3. Preserved mushrooms

These categories can also be used for the quality demands of the three groups.
3. The quality

  1. Fresh mushrooms

Only for button mushrooms and oyster mushrooms do quality classes exist.  For the other types of mushrooms it is therefore important to recognize them and their qualities individually.  Fresh mushrooms, whether wild or cultivated should be whole and firm.  They should also feel slightly moist but not wet as too much moisture causes discolouring, rotting spots and slime forming.  Dried or split stalks are a sign that they have too little moisture and have been harvested for some time.  They are better not used in a dish.  The colour and the fact that the mushroom caps are open or closed are also indicators of freshness.  The caps of ordinary white mushrooms should be white and completely closed at the stalk. If the caps are light brown or brown and the ribs of the mushroom showing, these mushrooms are obviously not fresh. Discoloured mushrooms with open caps are still edible but not storable.

fresh mushrooms

  1. Dried mushrooms

This category is more difficult to control for quality.  Often defects are discovered such as too much soil or unusable stalks only after the mushrooms have been soaked. It is advisable to look for soil in the packaging and to ensure that the mushrooms are regular in size ( especially if this is required for a dish.)

dried mushrooms

  1. Preserved mushrooms

Preserved mushrooms have less flavour than fresh or dried ones.  They are convenient in the preparation of soups and ragouts.  They can be selected for size and shape.  The same applies to truffles in tins or jars.  The black fungus has little flavour and aroma and is actually only suitable for decorating such as patés  and terrines. The liquid has more aroma.

Button Mushrooms


Class 1 – 1

Class 1 – 2

Mushrooms in this class must be of extremely high quality and contain all the hallmarks of the variety

Mushrooms in this class must be of high quality and contain all the hallmarks of the variety

They are hand-picked and free of spore moult and any developed spots on the surface

They are hand-picked and free of spore moult and any developed spots on the surface

These mushrooms must be white

These mushrooms must be white (or almost white)

Additionally they must be:
Perfectly shaped (or as good as), free from bruising (as far as possible), free from any kind of damage and as far as possible free from the casing layer (growth soil)

Allowances are made for:
Small deviations in shape, slight superficial damage, limited superficial bruising, small amounts of dekaarde that can be removed easily by washing

Classes 11 and 111 are sliced mushrooms

Used for industrial preserves

button mushrooms

Oyster Mushrooms


Class 1

Class 11

Mushrooms in this class must be of extremely high quality and contain all the hallmarks of the variety.  As long as the general appearance and storage time are not negatively influenced, the following defects are allowed:
Slight superficial damage and bruising, the oyster mushrooms may have a limited mycelium growth, the caps may be slightly cracked, they may be slightly rounded, the gills should be intact, the edges of the caps must not curl upwards

Mushrooms in this class must be of high quality and contain all the hallmarks of the variety. Oyster mushrooms not suitable for class 1 may be included in this class. As long as the general appearance and storage time are not negatively influenced, the following defects are allowed:
Slight damage and bruising, the oyster mushrooms may have limited mycelium growth, they may be slightly damp

(Charts of quality regulations for mushrooms and oyster mushrooms from Dutch origin)

oystermushroom

  1. The price

Since the supply of wild mushrooms is smaller and dependent on the season, they are generally more expensive than cultivated mushrooms.  This is true of both fresh and dried wild mushrooms.  In an effort to keep the costs limited, dried wild mushrooms can be mixed with cultivated varieties – the extra aroma and flavour of the wild varieties adding to the dish without it being too expensive.  Truffles are the most expensive of all as they are very rare.  Fresh truffle is not always used; an alternative can be truffle trimmings, parures of truffle liquid, or jus de truffles from a tin.

The handling of mushrooms in the kitchen

When handling mushrooms in the kitchen, distinction should be made between the various aspects:

  1. The delivery
  2. The storage
  3. The preparation
  4. The use
  1. The delivery

As is the case with all fresh deliveries, it is important to check that the mushrooms delivered are the variety ordered, and that the amount and quality are correct.

  1. The storage

Fresh mushrooms
Fresh mushrooms are very fragile and tend to lose their quality very quickly.  Most varieties cannot be stored for longer than a few days.  Fresh mushrooms must be stored in the cooling, preferably not close to products with a strong odour such as leek as the mushrooms will quickly absorb the odour.  They can be stored cleaned or un-cleaned.
Dirty mushrooms packed in boxes can best be stored in their original packaging. If they are packed in crates they should be covered with foil to avoid the mushrooms drying out.  Cleaned mushrooms should be kept cool and covered with one or two clean towels, again to avoid them drying out.
Dried and preserved mushrooms
Dried and preserved mushrooms can be stored for a long time, however just as other preserves, in the long term the flavour will decrease.  Storage for longer than six to eight months is not advised.  The use-by-dates on the packaging should be checked.

  1. The preparation

Fresh mushrooms
With the exceptions of cave or marl (named after the growing compost) mushrooms, all other mushrooms should be cleaned using a dry method.  If mushrooms are washed in water they easily lose their delicate aroma. This also happens if they are allowed to stand in a bowl of water and as well as losing flavour; they absorb the water and become watery and spongy.   Mushrooms should be cleaned, one for one with a special mushroom brush or wiped with clean kitchen paper.  Stubborn stains, soil residues and ugly spots can be scraped away with a small knife. Cave or marl mushrooms that are covered with a marl layer may be quickly rinsed in running water. When very fresh mushrooms are used, cleaning can consist of only cutting off a section of the stalk. If they are split, dried or affected by damp more work is required to prepare them than simply cutting off the stalk.  Shiitakes, morels and various other wild mushrooms require the whole stalk removed as they usually have a tough and woody.


Dried mushrooms
Dried mushrooms must be soaked for fifteen to thirty minutes before use.  They can be soaked in lukewarm water or in wine, port or a mixture of an alcoholic beverage and water.  They increase 100% in size during soaking, but do not use more liquid than is necessary, as the liquid will absorb the flavour.  For this reason it is important not to discard the soaking liquid but to sieve it (to remove any unwanted particles) and use it for the dish or the sauce.
Preserved mushrooms
Mushrooms, which have been preserved, are already cooked and need only be sliced ( or they be already sliced) – no other preparation is required.  Since they have been preserved, a lot of the flavour will have been absorbed into the preserving liquid, for this reason it is advisable to use the liquid in the sauce or soup.

  1. The use of mushrooms

Whether to use fresh, dried or preserved mushrooms, depends naturally on the dish that is to be made with them.  Some salads, filled mushrooms and fried mushrooms, can only be made with fresh mushrooms.  For soups, ragouts or salpicons, dried or preserved can be used and in some cases benefit from the extra flavour. The advantages of storing dried and preserved mushrooms can also outweigh in some occasions the use of fresh mushrooms.

Cultivation of mushrooms

Mushrooms are grown in cultivation cells (a type of small, windowless shed) with four of five layers of cultivation beds along the walls. Although the conditions that are optimal for growing button mushrooms is known, the actual process is still poorly understood because the substrate on which it grows is one which is undefined. The substrate on which mushrooms is cultivated include horse manure, wheat straw, corn cobs, several other plant wastes and some animal wastes such as feather meal and chicken manure. The composting process is a mixed fermentation involving a range of micro organisms, bacteria and other fungi, which will degrade some of the complex compounds such as lignin and cellulose. Due to the biological activities of the micro organisms, the compost is heated within half a day to 60º C and provides an environment that will be restricted to only a few micro organisms that will be heat tolerant. When the compost cools, (gradually during a week to 24º) a lot of ammonia is freed and it will have a consistency similar to that of thick oatmeal and will provide an environment well suited for mycelia growth.   Mycelia growth, at this point, is very rapid if maintained at the optimal temperature of 24º C. However, this temperature will vary according to the variety, which is being grown. Following growth of mycelium throughout the substrate, a casing layer, is placed over the substrate. The casing layer is normally composed rich, clay soil, which is nutritionally poor, relative to the compost on which the mycelium has been growing. The casing layer is critical in the fruiting body formation of mushrooms and is necessary for the initiation of fruiting. Why this is important is not known, but without this, step fruiting will not occur. The biological activity of bacteria, various soluble salts, together with the lowering of the temperature between 14-18 C, will optimise fruiting body production. To encourage this process the electric light is left on for 12 hours per day.   Formation of fruit bodies begin as mycelia strands, just below the surface of the casing layer, develop "nodules" which are composed of tightly interwoven mycelium that will eventually develop into button mushrooms (after one week the first mushrooms will appear above the soil). 
The first harvest is normally 25 to 27 days after the addition of the casing layer and continues until all the mushrooms have grown.  After two weeks, more mushrooms are ready to be harvested – this happens up to four or five times before the beds are eventually cleaned and the new compost applied.


The cultivation of other mushrooms (oyster, shiitakes, etc.) is practically the same with the only difference being that each type of mushroom requires different temperatures and humidity. Oyster mushrooms that grow in nature on wood (for example branches of trees that have been blown off) are cultivated on chopped wheat straw.  Shiitakes, which also grow naturally on wood are cultivated on sawed off tree trunks or sterilised wood shaving from oak or beach trees.
Agaricus bisporus is the species that you all know as the "button mushroom," and is the most cultivated mushroom in the world, but in Western culture, it was also the only species available until recently. The cultivation of this species began around 1650, in Paris France, in areas in which mushrooms were frequently collected on used compost from melon crops. For approximately 160 years, A. bisporus was grown in open fields. At some point, it was realized that mycelium, or what is referred to as the spawn of the mushroom, was what gave rise to the mushroom and could be utilized much like the seed of plants to grown mushrooms. Another significant discovery was light was not necessary for the growth of A. bisporus, which led to its successful cultivation in natural caves, quarries or excavated tunnels. The advantage of cultivating A. bisporus in caves was the cool, moist, uniform environment. In 1910, France began growing A. bisporus in mushroom houses, but caves are still the preferred growing structures for the production of mushrooms in France.
Cultivation of A. bisporus eventually spread to England, and by 1865, had reached the United States. At first, spawn for the mushroom was imported from England, but because of the time involved in shipping, the mushroom spawn was in poor condition by the time it had reached the United States and produced a poor quality of mushrooms. It would not be until 1903 before United States Department of Agriculture scientists developed its own spawn, thereby freeing the United States of its dependence upon English spawn, which had caused so many problems
Louis F. Lambert, a French mycologist, started the American Spawn Company of St. Paul Minnesota, the first producer of pure mushroom spawn in the United States. His product was sold across the country as "Lambert’s Pure Culture Spawn." This spawn received a silver medal at the Universal Exposition in St. Louis in 1904. A measure of Lambert’s success was that English spawn was soon being sold under the name "English Pure Culture Spawn.” By 1914, four to five million pounds of mushrooms were grown in the United States. The production cost to the mushroom grower ranged from fifteen to twenty-five cents a pound and retailed at forty to sixty cents per pound, and marketing aimed at the consumers became very important. Mushrooms were packed in attractive containers to make a good-looking product that sold well
In Holland mushrooms were also grown from the late 1800’s.  Particularly the damp marl groves of South Limburg were found to be particularly suited for this purpose. Till 1970 it was the main cultivation area.  However technical possibilities were forever improving, making a damp microclimate possible to imitate and in the fifties and sixties cultivation began in North Limburg and West Brabant.