Liquid culture recipes provide mycelium with the nutrients it needs for healthy growth, such as mixing together 4% sugar solution (light malt extract, honey or corn syrup) with distilled water.
Before beginning, take care to sterilize both your workspace and tools with cleaning alcohol or wipes, working under an open or laminar flow hood if possible to minimize contaminants.
Water
Liquid culture simplifies mushroom cultivation by growing mycelium in a sterilized liquid nutrient medium. Though sterile environments and special jars may be required, this technique provides a reliable and cost-effective means of producing high yields of mushroom spawn.
This recipe uses water and one or more common sugars to create a nutritious mixture that encourages mycelium growth before inoculating with mushroom spores. For optimal results, work in an area free from contamination; sterilize your jars using a pressure cooker if possible to prevent contamination.
Sugar provides energy to mycelial growth and should be broken down into simple sugars for healthy early stage development. Light malt extract is preferred for its high nutrient profile and clarity after sterilization, though honey may also be readily available. Aim for a sugar concentration of approximately 4-4% by mixing approximately 20g of sugar per 600ml of water – this ratio provides a balanced nutrient solution and can easily be adjusted by trying different sugar varieties.
Sugar
Most liquid culture recipes feature a sugar content of 4 percent by weight or lower; anything more could be toxic for early-stage mycelium growth. A wide range of sugar sources exist, such as light malt extract (with its specific nutritional profile) and corn syrups like Karo.
Some growers also utilize natural sweeteners such as agave nectar and other sources to supply additional sugars and nutrients for mycelial growth. Rice syrup or molasses provide similar carb profiles as malt extract.
Liquid cultures contain ingredients like soy peptone (a source of proteins and amino acids), yeast extract and potato flakes or rye flour for complex carbs in order to support mycelial growth. The purpose of making liquid cultures is to provide your spore colonization process with nourishment in order to accelerate it.
Nutrient Broth
Nutrient broth (also referred to as liquid culture (LC)) is mycelium suspended in nutrient medium that makes inoculating substrates and grain spawn easier, yet requires careful sterile work environment and technique in order to prevent contamination from mycelium growth – something which may become difficult to spot once mycelium starts growing within it.
LC recipes usually contain no more than 4% sugars and may include additions for protein, lipids, starches, minerals, vitamins and more. Additives may also serve to select for certain microbes.
Most nutrient broths can be purchased premade as mixes, or you can create your own by mixing 20g agar powder per 1L water and sterilizing in a mason jar or media bottle – you’ll find sterilizable containers online and at local hardware stores with modified lids specifically for inoculations purposes; to create your own, cap off with a screw top lid before placing into a pressure cooker set at 15 PSI for 20 minutes.
Mason Jars or Media Bottles
Growers often opt for glass jars or Mason bottles instead of disposable polystyrene Petri dishes due to their screw thread lids that enable reuse over and again. This method reduces costs associated with waste disposal costs.
These types of jars are popular for gifting homemade jams, jellies and preserves to loved ones as gifts. Additionally, they come in an assortment of sizes; one common use case being mushroom liquid culture culture.
Once the jars have been sterilized, liquid culture solution can be prepared using light malt extract or honey as the sugar source and water as the liquid medium. Once complete, this mixture should then be added to mushroom mycelium cultures for healthy growth; remembering to swirl or shake the jar frequently to prevent clumps or clouds forming and promote optimal health growth – some cultures require more frequent shaking than others.