One of the best and fastest ways to start colonizing mushroom substrate is by using a mushroom liquid culture.
Unlike mushroom spores, mushroom liquid culture is live mushroom mycelium suspended in a liquid solution, meaning the mushroom is already alive and starting to feed and grow on nutrients in the solution.
What is a mushroom liquid culture?
A mushroom liquid culture is a mixture of sterilized water, nutrient solution (sugar, raw honey, etc.) and live mushroom mycelium. The live mushroom mycelium will then feed on nutrient solution until the nutrients are completely depleted.
Once the live mycelium is fully colonized in the nutritious solution it can then be transferred to other mushroom growing substrates like agar, grains, or used to expand to more mushroom liquid culture.
How do you use it?
One of the easiest and fool proof ways to use liquid culture is via a mushroom liquid culture syringe. With a liquid culture syringe, you can easily inject live mushroom mycelium (inoculate) into your desired substrate. The liquid culture syringes are labeled with “CC’s”, making it easy to measure how much solution you are injecting into your substrate each time you use it.
A standard for one liter of grain is usually about 3-4 CC of mushroom liquid culture to help promote fast colonization. In some cases, less may be needed if the grains are already over saturated.
How do you make it?
To make a mushroom liquid culture starter you will need a few things:
- Widemouth masjon jar
- Jar lid with FAE (fresh air exchange) filter and injection port
- Stir bar or marble to help stir live mycelium
- Sugar(s) or raw honey (organic)
- Scale (in grams)
- Pressure cooker
- Tin foil
Step 1. Prepare Liquid Culture Jar Lid
The first thing you will need to do is prepare your mushroom jar lid.
The mushroom jar lid should have both a self healing injection port for inserting your liquid culture syringe and a FAE filter for gas exchange.
You can find out how to make your own mushroom jars lids here.
Step 2. Add Nutrient to Liquid Culture Jar
Next, you will want to weigh out your desired amount of nutrient for your mushroom liquid culture.
Some common sugars used to help feed the live mushroom mycelium in the liquid are the following:
- Honey raw (organic)
- Karo
- Corn sugar
- Light malt extract
- Dextrose (glucose)
In our example recipe we are going to use raw organic honey.
Take your scale and place your empty mason jar (500ml jar in this example).
Press “Tare” to zero out the weight reading.
Next, measure out 10 grams of raw honey.
Don’t worry if you are slightly under or over. It is best practice to have slightly less of the sugar nutrient as too much nutrient will stunt or kill the live mushroom mycelium.
Now that we have 10 grams of honey in our jar – add 250ml of hot water to the jar.
Once you have filled your jar with hot water, stir the jar to completely mix the solution.
At this point you will want to add a stir bar or marble to the jar. The stir bar or marble will be used to mix the solution after it is sterilized in the pressure cooker, and to provide FAE when the mycelium is colonizing the jar.
Step 3. Prepare Liquid Culture Jar for Pressure Cooker Sterilization
Now we are ready to add our jar(s) to the pressure cooker for sterilization.
*Please note: Due to the wide range of pressure cookers/safety precautions, please refer to your specific pressure cooker manual*
Break off a square of tin foil and cover your jar(s). This prevents any excess moisture from entering the jar and acts as a barrier from other jars touching each other inside.
Once you have covered your jars, begin loading your jars into the cooker.
*Refer to your pressure cooker manual for the amount of water to add, etc.*
Now that our jars are loaded, turn your heat source to High and wait for pressure to build to 15 PSI.
*Again, refer to your specific pressure cooker manual*
Once your pressure cooker has reached 15 PSI – maintain this pressure and set a timer for 20 minutes*
The amount of time can be controversial among mushroom growers, but any time longer than 20 minutes you may risk caramelizing your sugars.
Once your timer is up, remove pressure cooker from heat source to cool and let pressure return to ZERO on the pressure gauge.
