So, you’ve followed our Comprehensive Mushroom Cultivation Guide, and now you have a bunch of healthy looking grain jars. Problem is, now you’re out of spores or liquid culture — and let’s face it, you don’t want to buy more.
You can very easily make a (mostly) monocultural liquid culture using materials and equipment you likely already have, or can easily find nearby or online.
You will need at least two wide-mouth pint Mason jars, and two modified jar lids.
The first jar (sterile water) should be filled 3/4 to the top with distilled water, or clean, filtered tap water. The second jar (nutrient media) should be filled to the same amount, and also add 1/8 teaspoon Light Malt Extract. If you don’t have LME, you can use regular cane sugar, or even honey. Experiment with different sugars and ratios to figure out what your preferred cultivars and strains like.
These should be topped with modified lids and rings. Add the trivet to your Instant Pot Duo, add water above the base of the trivet, and add the sterile water jar and the nutrient media jar. Pressure Cook for 1 hour 30 minutes, with the Keep Warm setting turned off.
After allowing both jars to cool completely for 8-12 hours, or when cool to the touch, some sterile water can be drawn out of the jar with a 10cc syringe. You should sanitize both the needle and the injection port.
The sterile water can now be injected into a fully colonized spawn jar, and the jar rotated around gently to allow some of the hyphae to break off and become suspended in the fluid. You can then pull the fluid back out with the same syringe.
After holding up the fluid to the light and verifying that some hyphae are suspended in the water, you can now sanitize the needle once again and sanitize the injection port on the nutrient jar. Then you will insert the needle into the injection port on the nutrient media jar, and inject the hyphae into it. Ta-da! That’s Liquid Culture!
You can store the liquid culture in a dark place, around room temperature or a little cooler. Liquid cultures can remain viable for months or even years under the right conditions. Do not store them in the refrigerator alongside your food, as they are more likely to become contaminated. Purchase a separate refrigerator if you wish to chill them to prolong their life.
When you wish to use some of the liquid culture in order to inoculate more jars, you can simply sanitize the injection port and use a new syringe to withdraw the fluid. You can inoculate roughly 10 jars with a full 10cc syringe of LC.
A healthy liquid culture should eventually look like one or many white fuzzy masses of mycelium suspended in the nutrient media. The liquid itself should remain clear. If the liquid turns cloudy, or the jar begins to emit a foul smell, you should immediately discard the culture outdoors. Do not open it indoors.
