Product Overview : Mushroom Liquid Culture

What is Mushroom Liquid Culture?

Liquid Culture is a sterile mixture of water and one of a few specific sugars. (we will tell you how to make liquid culture below). The purpose of this nutritious mixture is to develop mycelium growth, once it has been inoculated with mushroom spores

You could think of liquid culture as mycelium floating in a nutrient broth. Liquid culture makes inoculating substrates easier. Once the mycelium has established itself in the nutritious, sugary broth, the mycelium-rich mixture can be inoculated onto a substrate of your choice or stored as a living mushroom culture.

What are the advantages of using Mushroom Liquid Culture?

• The risk of contamination is lower
• According to Liquid Culture Shroomery, using liquid culture reduces incubation time
• Limitless mycelium growth – once mycelium starts developing, it doesn’t stop

What are the disadvantages of using Mushroom Liquid Culture?

• A sterile working environment is essential
• Better suited for advanced mushroom cultivation
• You can’t see contamination in liquid culture. You will only know your mixture is contaminated when you use it.

What you will need:

• Grain spawn jar, also known as an airport jar
• Pressure cooker
• 10ml syringes
• Needles (Note: the bigger the number, the smaller the needle. We recommend 18 gauge)
• One of the following sugars, to mix with water: organic honey, corn syrup, corn sugar, light malt extract, dextrose (glucose).

Sucrose (household sugar) should not be used. For this guide, we chose honey.

What is the best sugar to water ratio?
A ratio of 4% is best.
This equates to 4cc, 4ml, or 1 teaspoon of honey per 100ml of water.
A 3% to  5% ratio is fine, but be aware, too much sugar (10% and more) is harmful to mycelium

A step-by-step guide to making your own mushroom liquid culture:

1. Carefully measure and mix the sugar you choose with water in the jar. Warm water will help the sugar dissolve quickly, but it is optional.
2. Put the lid on the jar.
3. Cover the top of the jar with aluminum foil and put it in a pressure cooker.
4. Cook at 15 psi for no longer than 15-20 minutes. Over-cooking the sugar will lead to caramelization, which will result in poor to no mycelium growth.
5. Allow the pressure cooker to cool off naturally before removing the jar. Be careful. The jar will be very hot.
6. Allow the jar and contents to reach room temperature.
7. Add some mother culture to your liquid culture. (more on where you can buy your mother culture below).

Important Note:
If you are not using an airport jar, don’t remove the lid until you are ready to inoculate your substrate and replace the lid as soon as you are done.  This will prevent airborne contaminants from entering the jar and ruining your mycelium.

How to add mother culture to your liquid culture

Once your jars have cooled after being in the pressure cooker, you can add a few ccs of mother culture. Shake the mother culture briskly to break up the mycelium.

If you are using a syringe needle for the first time, it should be sterile. If not, use a lighter or candle to sterilize the needle by holding it in the flame until it is red hot. Careful now! Use an alcohol wipe to cool the needle down.

Insert the needle through the self-healing injection hole in your airport jar lid and inject 1 to 2ml of liquid culture into the jar. Repeat if you have more than one jar.

What to do with a jar of mushroom liquid culture

Simply leave it on the shelf and wait for it to grow. Most mushroom cultures grow best at around 77°F (25 °C). Any variation in this temperature will cause them to grow more slowly.

Do not disturb the jars for 4 to 5 days. During this time, the mycelium enters its growth stage, and you will see it grow as it consumes the sugar. After the initial resting period, you should swirl the culture every couple of days to break up the mycelium and introduce oxygen into the culture.

When the mycelium has grown and almost fills the jar, vigorously agitate the liquid culture to break the mycelium up as much as possible. When you are ready to inoculate your substrate, transfer the culture to agar, or share some with your friends, tilt the jar so that the liquid reaches the injection port and, with a sterile syringe and needle, suck the culture into the syringe until it’s full

How to Use Liquid Culture to Grow the Perfect Mushrooms

There are a few more steps between having liquid mushroom culture and picking a crop of edible mushrooms.

The first step is expanding the mycelium. This can be done using different types of grains, such as rye, wheat, oat, birdseed, or corn seeds. You could also use cardboard or wood chips (for this guide, we chose grain).

Prepare the grain to receive the liquid culture

1. Soak, boil, and drain your grain
   

   Soak the grain for 12 to 24 hours before boiling to reduce cooking time. Cook for 10 minutes if soaked, or 20 minutes if not. The grain must be cooked for long enough to be hydrated and soft but not mushy. Overcooked grain is more likely to spoil. Remember, your grain will be placed on a pressure cooker again a little later, so rather have it undercooked at this stage.

   Useful Tip:
   Some people skip the boiling stage and go straight from soaking to bagging and then putting it in the pressure cooker.

   Drain the grain in a colander and then tip it onto a table lined with kitchen towel. Allow it to dry completely. You can use a dehumidifier and a fan to speed up the process. The grain cannot be warm or wet when you put it into the bag or it could become contaminated.

2. Put the grain in a bag and place it in a pressure cooker

   Cover your bags with aluminum foil to prevent them from melting if they come into contact with the side of the pot. A melted bag and the grain it contains have to be thrown away. Cook the bag of grain for 90 minutes at 15 PSI to sterilize.

3. Add the liquid culture

   Allow the bag of grain to cool, and then seal it with tape. Be careful not to block the filter patch as this allows for air exchange, without which the mycelium will not grow.

   At this stage, your bags are ready to be inoculated using your liquid mushroom culture. Or, in other cases, previously inoculated grain or agar.

   You will simply inject your liquid culture directly into the bag through the injection port. If you use bags that don’t have an injection port, inject through the tape and cover the needle-prick hole with another piece of tape.

4. Wait for your mycelium to grow
   

   Put your bag in an upright position somewhere where it will not be disturbed and where the temperature is between 75 and 81°F (24 to 27 °C). Ensure there is enough space between the filter, the plastic, and the grain to allow for air exchange. It doesn’t matter if it is light or dark. Within 3 to 10 days after inoculation you should see signs of growth. After 3 or 4 weeks, your mycelium should have colonized 70 to 75% of the bag. At this point (and not before, or you risk delaying the growth), you will need to use your hands to break up the grain through the bag to speed up the last phase of colonization. The mycelium will colonize the entire bag approximately three to seven days after it is broken up.

5. Spawn the colonized grain to a bulk substrate

   You will decide which bulk substrate you want to use based on the type of mushrooms in your liquid culture. For example, the Agaricus bisporus family (White Buttons, Cremini, and Portobello) like growing in manure or compost, oyster mushrooms like growing on anything made from wood, and straw mushrooms grow on straw, as their name suggests (read more about growing straw mushrooms here).

6. Tend to your mushrooms

   Depending on the type of mushroom you choose to grow, you will nurture and care for them until they are ready to harvest. We have a host of blogs about growing your own mushrooms on our website, so if you want any information about which ones are the easiest to grow, or the most nutritious, or even where to buy mushroom kits