In order to obtain a suitable growth medium for the Champignon mushroom (Agaricus bisporus), a very well balanced blend of raw materials must be used. The mushroom, a saprophyte, grows exclusively on decayed organic matter. For this substrate, water, straw, and chicken manure are the main raw materials. Plaster is also added.
The production of substrate begins with Phase I – fermentation. The goal is to produce a selective growth medium in which the proper nutrients are present. It is equally important to ensure that the ideal nutrients and conditions for other competing organisms are not present.
After all raw materials are mixed and a base mixture is obtained, the process begins. Many carbohydrates (sugars) are available in this mixture. Some of these carbohydrates are easily absorbed by many organisms, e.g. from different types of mould. On the other hand, the mushroom itself thrive carbohydrates that are not readily absorbed. It is therefore important to “compost away” the easily absorbed carbohydrates in order to produce a selective substrate. This requires bacteria, which are mixed into the raw materials. The bacteria consume these easily absorbed carbohydrates. Through the energy liberated, this process is carried out at about 80°C. This heating is caused only by the bacteria without external heating. To “compost away” the easily absorbed carbohydrates, these organisms need an oxygen supply. The process is therefore aerated.
The Phase I substrate preparation takes place in a composting bunker or substrate hall as a computer-controlled process. Such bunkers are closed, ventilated, concrete rooms, which hold up to 700 tonnes of substrate, for example, at our site in Tietzow. The entire process takes eight to ten days
As a result of eight hours of pasteurisation at 58°C, the microbiologically decomposed, homogenised substrate is rid of unwanted foreign organisms. After five days of conditioning, substrate is formed which can then be colonised by the mushroom.
The substrate is now inoculated with mycelium – the filamentous cells of the mushroom. Under strictly controlled hygienic conditions and a temperature between 24–26°C, the substrate is colonised by mushrooms within two to three weeks.
The carefully produced, high-quality substrate is primarily for our own use. A smaller proportion is sold to other mushroom farms.
For the formation of fruiting bodies, the substrate is packed into boxes and covered with a layer of peat. Humidity, temperature, and the CO2 content of the air are monitored by a climate control system. At an air temperature of approximately 17°C, the first mushrooms are harvested after just two weeks. In the following weeks, the mushrooms are handpicked in two to three harvests of three to five days each. We can harvest about 30 kg of mushrooms from one square metre of substrate.