Many people, especially in Asia, are under the impression that because wild Reishi is rare and very expensive it must be of better quality than the cultivated version, therapeutically speaking. A common mistake this is, mixing up price and value. The opposite is true, however. Wild Reishi is easily damaged and contaminated by insects, moulds, environmental pollution and the overall amount of bioactives is very inconsistent, resulting in an unreliable quality. It rarely reaches full maturity in perfect condition. Cultivated Reishi on the other hand is usually based on strains selected for their therapeutic potency and it can be grown under well controlled circumstances. This results in a more uniform and reliable product.
The first recorded attempts at cultivation were made in 1937, but mass production was not possible until 1971, when the Japanese developed a cultivation method using pots with sawdust. Cultivation techniques have developed further since then.
Currently the most commonly used are the following three cultivation methods:
a) Wood log cultivation
This was found to be the most effective method, resulting in superior quality Red Reishi with significant and uniform levels of the desired bioactive constituents. Indoor cultivation gives the maximum level of control over contamination. It is expensive, because it requires specific types of wood, which have to be seasoned and prepared. These wood logs are so-called ‘duanwood’ which means ‘original wood’ – the same wood Reishi grows on in nature. After inoculation with Reishi spawn they are buried in nutrient-rich soil.
Maturing Reishi of superior quality growing indoors on a prepared wood log.
Extensive time is required for fruiting body harvest (5-12 months), during which the developing mushrooms have to be water sprayed and maintained daily. Maintaining the correct humidity levels and temperature is very important. In combination with high quality Reishi strains this is the best option for growing therapeutically potent Reishi.
b) Saw dust / wood chips in bags.
The mushrooms are cultivated in bags or bottles filled with wood chips and saw dust. Much cheaper than the wood log method, but the resulting Reishi fruiting bodies are smaller and were found to have a lower level of bioactives, even when high quality Reishi strains were used as a base.
Reishi grown on woodchips
c) Bioreactor cultivation using liquid substrate.
Reishi mycelia are grown in tanks in liquid substrate (also known as ‘deep layer cultivation’). Much research has been done to define the best strain/substrate combinations, because this is by far the cheapest method, in particular because it does in general not rely on fruiting body development, which takes a lot of time.
Bioreactor cultivation can be controlled 100%. However, so far the resulting Reishi products are not of the same quality as the sawdust method and not even close to the level of wood log cultivation.
The levels of therapeutically interesting constituents increase as the mycelia are about to develop into the fruiting stage. During bioreactor cultivation this stage is never reached, because of the time involved, and the more time is needed, the more expensive the final product will become. The main reason for a producer to choose bioreactor cultivation is that it is fast and therefore cheap. The poor quality Reishi it produces is taken for granted and usually masked with smart and deceiving marketing tricks.
A general quality marker since ancient times has always been the bitterness of the product: the more bitter, the higher the quality.The bitterness is caused by the presence of specific triterpenes. Reishi mycelia are not bitter at all. They contain less bioactives than the fruiting bodies, in particular the triterpene-percentages are lower and nucleosides are completely absent. The development of these is highly dependant on the procedures used during bioreactor cultivation.
Triterpenes are secondary metabolites, constituents which are not essential for the mushroom’s growth (these are primary metabolites) but develop only to help the -parasitic-mushroom cope with its harsh environment and with host invasion. In a sterile lab tank these secondary metabolites will therefore not develop well unless artificially triggered. Research on the best ways to do so is still on-going.
This is also the reason why attempts at cultivating Chaga (Inonotus obliquus, a slow-growing medicinal fungus with similar lanostane-type triterpenes), have so far not resulted in quality products, therapeutically speaking.
What about Reishi spore products ?