Liquid culture is an invaluable way to quickly grow mushrooms at home, as it accelerates mycelium formation while being easy to control.
An effective liquid culture recipe typically calls for mixing honey, light corn syrup (Karo) or dextrose with water before sterilizing the solution and adding mushroom spores.
Ingredients
Liquid culture mushroom farming involves inoculating nutrient-rich solutions with spores and mycelium to grow mushrooms on a larger or individual scale, with liquid cultures having the power to greatly accelerate colonization rates as opposed to using traditional spore inoculation methods.
Liquid cultures contain ingredients essential for healthy early-stage mycelium development. For maximum growth and adaptability, the optimal recipes incorporate multiple sources of nutrients that promote mycelial growth and adaptation.
Typically, a 500 milliliter mixture of filtered or non-chlorinated water, Karo light corn syrup and peptone or light malt extract must be prepared, stirring to dissolve all components. After stirring has taken place, use a magnetic stir bar in your jar before sterilizing with 15 PSI pressure for 25 minutes to ensure safe storage and distribution.
Some growers opt for potato dextrose agar instead of Karo and malt extract for growing purposes. To create this mixture, two peeled and chopped potatoes must first be boiled in 500 milliliters of water for 30 minutes, before the liquid from this boil-off is combined with 20g of dextrose and combined with agar before stirring until all has dissolved completely.
Containers
Liquid culture offers home cultivators an ideal option with low maintenance requirements and requires few sterile components – typically including laminar flow hoods or glove boxes, sterile syringes and glass jars – in order to prevent contamination.
Liquid culture recipes typically consist of mixing sugar with water to provide young mycelium with essential nutrients, such as honey, corn syrup or light malt extract. Other ingredients may also be included, such as minerals for early mycelium growth or blood agar as an energy source for chemoheterotrophs.
Mason jars and media bottles make ideal containers for liquid culture experiments, as they are sterilizable and allow enough room for mycelium growth. Furthermore, mycology jar lids offer injection ports and filters to facilitate contamination-free gas exchange.
Sterilization
Due to the vulnerability of liquid culture nutrient solutions, it’s crucial that they’re handled as efficiently and cleanly as possible; working under a laminar flow hood would be ideal. Before handling your jars, thoroughly cleanse all surfaces and tools with 70% isopropyl alcohol before donning gloves for extra safety.
Mason jars designed specifically for mycology can be purchased with modified lids that feature an injection port for sterile inoculation and filter for clean air exchange, along with pre-inoculated grain substrate, to minimize costs and setup times.
To inoculate the jar, use a sterilized syringe and needle to inject your chosen mushroom spores or culture. After inoculation, periodically shake or stir your jar to evenly disperse mycelium for consistent growth; you can do this either with a magnetic stirrer or by gently shaking by hand.
Incubation
Liquid culture can be relatively inexpensive and straightforward to complete at home, since only basic ingredients and minimal equipment is needed. But as with all techniques there can be risk of contamination; to minimize that risk it is vital that both workspace and equipment remain sterile before adding mushroom mycelium to an already sterilized nutrient solution. Otherwise you risk producing culture that becomes overly cloudy without producing mycelium quickly, or may produce it at all; you might even end up with white clumps that form irregularly-shaped mycelium production!
Start with sterilized mason jars or media bottles and place a magnetic stirrer or glass marble in each jar to facilitate stirring and distribute nutrient broth evenly across them. Carefully monitor mycelium growth over the following week or so – full colonization should occur between 2 and 4 weeks later – when your mycelium has fully colonized, store them in the fridge to slow mycelium metabolism and extend their shelf life.