Thursday 8 January 2015

Strain spotlight: the brown-cap oyster mushroom (Pleurotus ostreatus 213)


Pleurotus ostreatus, or the oyster mushroom, is one of the world’s most easily cultivated edible fungi. As its Latin name “Pleurotus” implies the oblong caps of this tasty mushroom grow horizontally or sideways with respect to its vertical stem, and “ostreatus” refers to resemblance it shares with the oyster, a marine mollusk, making it just as easy to identify in the misty forests of the North-Western United States as it is in balmy India or subtropical New Zealand. Despite its global reputation, each oyster mushroom strain posses distinct traits, which dynamically alter its appearance, flavor, and its ability to be cultured, making a strain from China incomparable to a strain isolated from Florida. In this excerpt Pleurotus ostreatus 213will be characterized for its individual qualities as well those it shares with oyster mushrooms as a whole.
Oyster mushroom strain 213
The distinct aesthetic, culinary, and adaptational characteristics of Pleurotus ostreatus 213 make it the ideal choice for beginner and master cultivators alike. Pleurotus ostreatus 213produces feathery, delicate caps that grow in a unique shingling pattern; this layering of fruit bodies minimizes the potential for dehydration and contamination to occur (favoring mushroom enthusiasts who are just getting started!). Its light brown caps are more photosensitive than a number of strains, providing a challenge to more experienced cultivators by developing growing conditions to obtain the ideal coloration for the optimal aesthetic dining experience.

The petite crowns of strain 213 provide benefits to any number of culinary endeavors. Due to the perfect size of the caps, these mushrooms require minimal preparation (the better to preserve the earthy flavor) and can be consumed in just a few bites. The velvety caps can be sautéed in cream for an almondy-rich sauce or combined with butter for a delectable meal in and of themselves.  The stems can be added to a stir fry to provide a woody contrast texture to an otherwise flat meal or removed later after the delicious mushroom flavor has seeped into the other vegetables. Even the mycelium can provide a cultivator with a delicious and nutritious supplement if dried and ground when added to tea, juice, or even bread and meatloaf.

 Pleurotus ostreatus 213 also holds the unique adaptation of being drought tolerant, making this strain perfect for drier climates. The wide range of temperatures (50-70 degrees Fahrenheit) optimal for fruiting this strain allows it to adapt to a number of environments. Six to eight weeks after colonization, fruiters are able to achieve 150% biological efficiency, and they are well into their third or fourth flush of premier oyster mushrooms (with many more to come!). When the block or bag of spawn is spent it can be recycled in compost or a garden to establish a prosperous micro-biota to enrich soil for crop production.

Pleurotus ostreatus 213 is a unique strain, having many exceptional individual characteristics, but it still belongs to the oyster mushroom group as a whole, so it shares the qualities of being able to colonizing a great number of substrates as well as being receptive to numerous decontamination techniques with all Oysters. Oyster mushrooms can grow on virtually any plant based material, and strain 213 is no exception to this rule. Many oyster mushrooms prefer a substrate low in lignin (the compound responsible for the structure of wood) such as straw, hard wood sawdust, and agricultural waste products like corn cobs, but it can grow just as prolifically on card board, fall leaves, coffee grounds, or any other plant based waste common to households.

Oyster mushrooms are a hearty group allowing for the substrate to be disinfected by lime pasteurization, soap, hot water, ash, or heat sterilization techniques. To perform a disinfection step, soak the substrate (straw is recommended for this method) in a solution of hydrated lime. The exact concentration is not critical but the pH should be high and when the straw is added, the solution should be a milky yellow color. Submerge the straw or choice substrate, weight it down so it does not float, and wait 12 to 24 hours. After soaking, drain the excess water, bag the straw and inoculate it with Pleurotus ostreatus 213 spawn. Soap is also a good disinfection agent. Make a strong soap solution, soak 12 to 24 hours; drain the excess water and inoculate. Oyster Mushrooms use straw and the soap as a nutrient source, so there is no residue soap left in the mushrooms; it is all bio-converted into mushroom tissue. The hot water method can also be used to pasteurize substrate. Either boil water and pour it onto the substrate, and allow it to soak until the water has cooled or boil the substrate in water for 1 hour (depending on the size of the operation). Drain the excess water. Bag and inoculate the substrate. Ash is a third means to pasteurize a substrate, and it follows the same procedure as the lime technique. Finally, the ultimate method to insure optimal sterilization of a substrate is to treat it with heat either in a pressure cooker or an autoclave. Depending on the specifics of the machine pressures will vary but the substrate should reach 121 degrees Celsius for 15-45 minutes. Allow the substrate to cool before inoculation procedures.

Oyster mushrooms are a well known group of mushrooms that are easy to work with for beginners, but they can also provide a challenge in developing the perfect flush for cultivators who are more experienced. While Oyster mushrooms as a group have many beneficial qualities for propagation like the ability to colonize versatile substrates and respond to any disinfectant technique, individual strains like Pleurotus ostreatus 213 have unique traits such as appearance, flavor, and adaptations that set them apart from the rest.

This excellent strain might be purchased from Aloha Medicinals Inc. in form of culture or grain spawn


Written by Haley Toups



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